Publications by year
In Press
Phillips B, Bullock J, Osborne J, Gaston K (In Press). Ecosystem service provision by road verges. Journal of Applied Ecology
Roberts B, Cox R, Osborne J (In Press). Quantifying the relative predation pressure on bumblebee nests by the European badger (Meles meles) using artificial nests.
Ecology and EvolutionAbstract:
Quantifying the relative predation pressure on bumblebee nests by the European badger (Meles meles) using artificial nests
Bumblebee populations are declining. Factors that impact the size and success of colonies act either by limiting resource availability (bottom-up regulation) or by causing mortality e.g. pesticides, disease and possibly predation (top-down regulation). The impact of predation has not been quantified and so the current study used novel artificial nests as a proxy for wild bumblebee nests to quantify the relative predation pressure from badgers in two habitats: woodland and grassland, and at two nesting depths: surface and underground. Badgers occur across most parts of the UK, and are known to predate on bumblebee nests. We found that significantly more artificial nests (pots containing bumblebee nest material) were dug up compared to control pots (pots without bumblebee nest material). This shows that artificial nests have the potential to be used as a method to study the predation of bumblebee nests by badgers. In a location of high badger density, predation pressure was greater in woodland than grassland, whereas no difference was observed in relation to nest depth. Woodland and grassland are shared habitats between bumblebees and badgers and we suggest that higher predation may relate to activity and foraging behaviour of badgers in woodland compared to grassland. We discuss how badger predation in different habitats could impact different bumblebee species according to their nesting behaviours. Understanding the relative impact of badger predation on bumblebee colonies provides key information on how such top-down regulation affects bumblebee populations.
Abstract.
Phillips B, Navaratnam A, Hooper J, Bullock J, Osborne J, Gaston K (In Press). Road verge extent and habitat composition across Great Britain. Landscape and Urban Planning
Phillips BB, Bullock JM, Osborne JL, Gaston K (In Press). Spatial extent of road pollution: a national analysis. Science of the Total Environment
2023
Kennedy P, Osborne J (2023).
A review of the success of the UK strategy to tackle the invasive insect Vespa velutina nigrithorax, the “Asian hornet”. 23 pages.
Abstract:
A review of the success of the UK strategy to tackle the invasive insect Vespa velutina nigrithorax, the “Asian hornet”
Abstract.
Poidatz J, Chiron G, Kennedy P, Osborne J, Requier F (2023). Density of predating Asian hornets at hives disturbs the 3D flight performance of honey bees and decreases predation success.
Ecol Evol,
13(3).
Abstract:
Density of predating Asian hornets at hives disturbs the 3D flight performance of honey bees and decreases predation success.
Automated 3D image-based tracking systems are new and promising devices to investigate the foraging behavior of flying animals with great accuracy and precision. 3D analyses can provide accurate assessments of flight performance in regard to speed, curvature, and hovering. However, there have been few applications of this technology in ecology, particularly for insects. We used this technology to analyze the behavioral interactions between the Western honey bee Apis mellifera and its invasive predator the Asian hornet, Vespa velutina nigrithorax. We investigated whether predation success could be affected by flight speed, flight curvature, and hovering of the Asian hornet and honey bees in front of one beehive. We recorded a total of 603,259 flight trajectories and 5175 predator-prey flight interactions leading to 126 successful predation events, representing 2.4% predation success. Flight speeds of hornets in front of hive entrances were much lower than that of their bee prey; in contrast to hovering capacity, while curvature range overlapped between the two species. There were large differences in speed, curvature, and hovering between the exit and entrance flights of honey bees. Interestingly, we found hornet density affected flight performance of both honey bees and hornets. Higher hornet density led to a decrease in the speed of honey bees leaving the hive, and an increase in the speed of honey bees entering the hive, together with more curved flight trajectories. These effects suggest some predator avoidance behavior by the bees. Higher honey bee flight curvature resulted in lower hornet predation success. Results showed an increase in predation success when hornet number increased up to 8 individuals, above which predation success decreased, likely due to competition among predators. Although based on a single colony, this study reveals interesting outcomes derived from the use of automated 3D tracking to derive accurate measures of individual behavior and behavioral interactions among flying species.
Abstract.
Author URL.
Lonighi A (2023). Effects of non-native species and ecological restoration on network structure and ecosystem function.
Abstract:
Effects of non-native species and ecological restoration on network structure and ecosystem function
Non-native species pose a signi cant threat to biotic interactions, such as plantpollinators,
and associated ecosystem functions. Ecological restoration is commonly
used to mitigate or revert the impact of non-native species. The removal of nonnative
plants is one frequently used restoration approach to minimise competition
for resources between native and non-native plants, which facilitates the recovery
of native plant communities. Many aspects of how ecological restoration impacts
native ecosystems are not well understood. For example, the conditions that allow
ecological communities to thrive after restoration can take years to develop. Although
restoration interventions ideally aim to address most impacts of non-native
species, we know little about the response of non-target species, both native and
non-native.
In this thesis, I explore the effects of non-native species and ecological restoration on
plant-pollinator communities and pollination function on the island of Mahé, Seychelles,
in the Western Indian Ocean. I used a community-level restoration experiment
with honey bee (Apis mellifera) supplementation to study the medium-term
responses of plant-pollinator interaction networks to management interventions. Initial
restoration took place in 2011, and the datasets used here were collected across
two consecutive years (2018/19 and 2019/20).
Abstract.
Rojas-Nossa SV, O'Shea-Wheller TA, Poidatz J, Mato S, Osborne J, Garrido J (2023). Predator and pollinator? an invasive hornet alters the pollination dynamics of a native plant. Basic and Applied Ecology, 71, 119-128.
2022
Allen-Perkins A, Magrach A, Dainese M, Garibaldi LA, Kleijn D, Rader R, Reilly JR, Winfree R, Lundin O, McGrady CM, et al (2022). CropPol: a dynamic, open and global database on crop pollination.
Ecology,
103(3).
Abstract:
CropPol: a dynamic, open and global database on crop pollination.
Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open, and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry mass, number of fruits, and fruit density [kg/ha], among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), North America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-2005 (21 studies), 2006-2010 (40), 2011-2015 (88), and 2016-2020 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e. proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA).
Abstract.
Author URL.
Poidatz J, Chiron G, Kennedy P, Osborne J, Requier F (2022). Density of predating Asian hornets at hives disturbs the 3D flight performance of honey bees and decreases predation success.
Kahane F, Osborne J, Crowley S, Shaw R (2022). Motivations underpinning honeybee management practices: a Q methodology study with UK beekeepers.
Ambio,
51(10), 2155-2168.
Abstract:
Motivations underpinning honeybee management practices: a Q methodology study with UK beekeepers
AbstractBeekeepers are central to pollinator health. For policymakers and beekeeping organisations to develop widely accepted strategies to sustain honeybee populations alongside wild pollinators, a structured understanding of beekeeper motivations is essential. UK beekeepers are increasing in number, with diverse management styles despite calls for coordinated practice to manage honeybee health. Our Q methodology study in Cornwall, UK, indicated five beekeeping perspectives; conventional hobbyists, natural beekeepers, black bee farmers, new-conventional hobbyists and pragmatic bee farmers. Motivations can be shared across perspectives but trade-offs (notably between economic, social responsibility and ideological motivations) result in differing practices, some of which counter ‘official’ UK advice and may have implications for pollinator health and competition. Honeybee conservation emerged as a key motivator behind non-conventional practices, but wild pollinator conservation was not prioritised by most beekeepers in practice. Q methodology has the potential to facilitate non-hierarchical collaboration and conceptualisation of sustainable beekeeping, moving towards co-production of knowledge to influence policy.
Abstract.
Clements J (2022). Understanding English agri-environment. schemes: uptake, engagement and. outcomes.
Abstract:
Understanding English agri-environment. schemes: uptake, engagement and. outcomes
The Agriculture Act (2020) proposes that future agri-environment schemes (AES) are framed around the principle of ‘public money for public goods’. While
it is too early to fully assess the impacts of this Act, Defra intends to open new agri-environment schemes to applications in 2024, and pilots began in 2021.
This presents a window of opportunity in which it should be possible to design schemes that are better able to engage participants and cultivate the intrinsic
values that are necessary for ‘culturally sustainable’ participation in environmental approaches (Burton and Paragahawewa, 2011; Chan et al.
2016). However, it has been claimed that more research is needed on the social processes that underlie successful environmental management programmes involving farmers (de Snoo et al. 2013, p. 67). This project seeks to fill this gap by addressing two research questions:
• What factors explain farmers’ participation and engagement, or lack thereof, in agri-environment schemes?
• How can this evidence inform future policy focused on improving the effectiveness of agri-environment schemes?
These questions are approached using a mixed methodology; a statistical analysis of quantitative Farm Business Survey Data using a Generalised Linear
Model and a case study in the county of Cornwall, including interviews, analysed thematically and using Qualitative Comparative Analysis. This allowed
the research to approach agri-environment scheme participation and engagement holistically while testing a novel methodology. The results of this
research are discussed in relation to published literature on values, scheme design, and attitudes and behaviour, using a pragmatist epistemology.
An overemphasis on the choices of individual farmers, as opposed to the operational pressure of the wider agricultural industry and its institutions, risks
schemes not contributing significantly to meeting climate mitigation and biodiversity targets. In this vein, adjusting agri-environment schemes without
wider changes to the food production system will not engender the desired improvements to uptake, engagement and outcomes, and there are significant
research gaps around interventions that offer simultaneous environmental, economic and cultural benefits. A a result, this research has included both an
individual and a system focus. The quantitative analysis identified factors such as production type that influenced land managers’ participation in agri environment schemes, while the qualitative and comparative approaches highlighted pathways to participation and engagement in the context of
Cornwall. It is concluded that agri-environment schemes would benefit from having a place-based focus, supported by the provision of expert advice and
reskilling for land managers. In addition, scheme goals should be supported by wider agricultural and environmental policy, including in the form of a stringent regulatory baseline and potentially intervention elsewhere in the supply chain,
including in processing and retail.
Abstract.
2021
Twiston-Davies G, Becher MA, Osborne JL (2021). BEE-STEWARD: a research and decision-support software for effective land management to promote bumblebee populations.
Methods in Ecology and Evolution,
12(10), 1809-1815.
Abstract:
BEE-STEWARD: a research and decision-support software for effective land management to promote bumblebee populations
The demand for agent-based models to explore the effects of environmental change on pollinator population dynamics is growing. However, models need a simple yet flexible interface to enable adoption by a wide range of stakeholders. We introduce BEE-STEWARD: a research and decision-support software tool, enabling researchers, policymakers, land management advisors and practitioners to predict and compare the effects of bee-friendly management interventions on bumblebee populations over several years. BEE-STEWARD integrates the BEESCOUT and Bumble-BEEHAVE agent-based models of bumblebee behaviour, colony growth and landscape exploration into a user-friendly interface, with reconstructed code, and expanded functionality. Bespoke automatic reports can be created to illustrate how different land management interventions can affect the densities of bumblebees and their colonies over time. BEE-STEWARD could be an important virtual test bed for scientists exploring the impacts of different stressors on bumblebees and used by those with little or no modelling experience, enabling a shared methodology between research, policy and practice.
Abstract.
Shaw RF, Christman K, Crookes R, Gilbert CN, Osborne JL (2021). Effect of height and colour of bee bricks on nesting occupancy of bees and wasps in sw england.
Conservation Evidence,
18, 10-17.
Abstract:
Effect of height and colour of bee bricks on nesting occupancy of bees and wasps in sw england
Bee bricks are a novel solitary-bee nesting habitat made from reclaimed concrete, designed to be built into walls to provide nest sites in urban areas. We tested if cavity-nesting bees and wasps used bee bricks, and if they showed any preference for nesting in bricks of different colours or at different heights. We carried out surveys of solitary bees in 15 private urban gardens and eight rural public gardens, where the bee bricks were then placed for two years (2016-2017). Bee bricks were placed on structures that were either 1 m in height with 4 bricks (red, yellow, white and wooden control) or with three platforms where white bricks were placed at 0 m, 0.6 m or 1.0 m above the ground. The number of occupied nest holes was counted at the end of each summer. Nesting holes that were capped with mud were more common than those capped with chewed or cut leaves. The average % of holes capped with either mud or chewed leaf was greatest in red bricks and lowest in wooden controls. Only one brick out of 39 placed at ground level had capped holes, although the difference in the % of holes capped between heights was not statistically significant. Cavity-nesting bees and wasps use solitary-bee bricks for nests, but population level impacts are still untested.
Abstract.
Horn J, Becher MA, Johst K, Kennedy PJ, Osborne JL, Radchuk V, Grimm V (2021). Honey bee colony performance affected by crop diversity and farmland structure: a modeling framework.
Ecol Appl,
31(1).
Abstract:
Honey bee colony performance affected by crop diversity and farmland structure: a modeling framework.
Forage availability has been suggested as one driver of the observed decline in honey bees. However, little is known about the effects of its spatiotemporal variation on colony success. We present a modeling framework for assessing honey bee colony viability in cropping systems. Based on two real farmland structures, we developed a landscape generator to design cropping systems varying in crop species identity, diversity, and relative abundance. The landscape scenarios generated were evaluated using the existing honey bee colony model BEEHAVE, which links foraging to in-hive dynamics. We thereby explored how different cropping systems determine spatiotemporal forage availability and, in turn, honey bee colony viability (e.g. time to extinction, TTE) and resilience (indicated by, e.g. brood mortality). To assess overall colony viability, we developed metrics, PH and PP, which quantified how much nectar and pollen provided by a cropping system per year was converted into a colony's adult worker population. Both crop species identity and diversity determined the temporal continuity in nectar and pollen supply and thus colony viability. Overall farmland structure and relative crop abundance were less important, but details mattered. For monocultures and for four-crop species systems composed of cereals, oilseed rape, maize, and sunflower, PH and PP were below the viability threshold. Such cropping systems showed frequent, badly timed, and prolonged forage gaps leading to detrimental cascading effects on life stages and in-hive work force, which critically reduced colony resilience. Four-crop systems composed of rye-grass-dandelion pasture, trefoil-grass pasture, sunflower, and phacelia ensured continuous nectar and pollen supply resulting in TTE > 5 yr, and PH (269.5 kg) and PP (108 kg) being above viability thresholds for 5 yr. Overall, trefoil-grass pasture, oilseed rape, buckwheat, and phacelia improved the temporal continuity in forage supply and colony's viability. Our results are hypothetical as they are obtained from simplified landscape settings, but they nevertheless match empirical observations, in particular the viability threshold. Our framework can be used to assess the effects of cropping systems on honey bee viability and to develop land-use strategies that help maintain pollination services by avoiding prolonged and badly timed forage gaps.
Abstract.
Author URL.
Clements J, Lobley M, Osborne J, Wills J (2021). How can academic research on UK agri-environment schemes pivot to meet the addition of climate mitigation aims?. Land Use Policy, 106, 105441-105441.
Phillips B, Bullock J, Gaston K, Hudson-Edwards K, Bamford M, Cruse D, Dicks L, Falagan C, Wallace C, Osborne J, et al (2021). Impacts of multiple pollutants on pollinator activity in road verges. Journal of Applied Ecology
Phillips BB, Bullock JM, Gaston KJ, Hudson-Edwards KA, Bamford M, Cruse D, Dicks LV, Falagan C, Wallace C, Osborne JL, et al (2021). Phillips et al (2021) “Impacts of multiple pollutants on pollinator activity in road verges” J Applied Ecology (dataset).
Abstract:
Phillips et al (2021) “Impacts of multiple pollutants on pollinator activity in road verges” J Applied Ecology (dataset)
The study was carried out in Cornwall, United Kingdom in 2019 and 2020. First, we used roadside surveys to assess the spatial distribution of pollution, flowers and pollinators in road verges. Second, we used field experiments (away from roads) to simulate each form of pollution separately and measure the impacts on pollinator densities and foraging behaviour to explain the distribution of pollinators observed across road verges.
Abstract.
Phillips B (2021). Roads, verges and nature.
Abstract:
Roads, verges and nature
Roads form vast and pervasive networks across the earth, with diverse and often profound negative environmental impacts. However, these roads are bordered by a parallel network of habitats in the form of road verges. In this thesis, I propose that roads present a nearly ubiquitous environmental pressure, but that their verges offer an equally widespread opportunity to benefit nature, the environment and, as a result, people.
I begin by using spatial mapping and modelling to estimate the extent of road pollution, in various forms, across Great Britain. This reveals that half of land is less than 216 m from a road, and that roads have a zone of influence that extends across > 70% of the land area. Whilst high levels of road pollution are estimated to be relatively localised, low levels are pervasive.
Second, I synthesise the literature to determine the global potential of road verges for mitigating such pollution, for supporting nature and for providing further environmental and social benefits via ecosystem services. I estimate that road verges may currently cover 270,000 km2 globally, and that they provide a wide range of benefits, including biodiversity provision, regulating services (e.g. air and water filtration) and cultural services (e.g. health and aesthetic benefits by providing access to nature). However, verges also displace other habitats and provide ecosystem disservices (e.g. plant allergens and damage to infrastructure).
Third, I use satellite and ground-level imagery to estimate the extent of road verges across Great Britain and to explore their potential to benefit nature, the environment and people. I estimate that there are 2579 km2 (2149-3010 km2) of road verges in Great Britain, equivalent to 1.2% of land area, of which 707 km2 (27.5%) is short, frequently-mown grassland, 1062 km2 (40.9%) is regular grassland, 480 km2 (18.7%) is woodland, and 272 km2 (10.7%) is scrub. Only 27% of frequently-mown grassland verges contain trees, indicating potential for planting trees and shrubs to provide environmental and social benefits.
Fourth, I take insect pollinators as a case study and, using a combination of roadside surveys, field experiments, a literature review, and meta-analyses, determine the suitability of road verges for pollinator conservation, and how they could be enhanced for this purpose. The findings demonstrate that road verges can be hotspots of flowers and pollinators in human-dominated landscapes, but that traffic and road pollution can cause mortality and other negative impacts on pollinators. Surveys in Cornwall, UK, show that pollinator densities are lower closer to the road edge – particularly within the first 2 m (55% lower than at 7-9 m) – where pollution is greatest. Field experiments reveal that these trends can be explained by pollinators being deterred by turbulence, and avoiding concentrations of metals that are more frequently found in flowers within 2 m of roads. Overall, evidence suggests that the benefits of road verges for pollinators outweigh the negative impacts of road pollution and pollinator-vehicle collisions.
The research shows clearly that road verges already provide many environmental and social benefits, but that these could be enhanced considerably through strategic design and management. Several reoccurring management recommendations are reducing mowing frequencies to no more than twice per year, leaving some areas uncut on rotation, and planting trees in urban verges and in low quality verge habitats. I finish by reflecting on the project and its outcomes, and on the remaining barriers to managing road verges for nature, the environment and people. This reveals the most important directions for future research, namely, the importance of overcoming social barriers to change that inhibit uptake of environmental management recommendations.
Abstract.
2020
Phillips BB, Wallace C, Roberts BR, Whitehouse AT, Gaston KJ, Bullock JM, Dicks LV, Osborne JL (2020). Enhancing road verges to aid pollinator conservation: a review. Biological Conservation, 250, 108687-108687.
Shaw RF, Phillips BB, Doyle T, Pell JK, Redhead JW, Savage J, Woodcock BA, Bullock JM, Osborne JL (2020). Mass-flowering crops have a greater impact than semi-natural habitat on crop pollinators and pollen deposition.
Landscape Ecology,
35(2), 513-527.
Abstract:
Mass-flowering crops have a greater impact than semi-natural habitat on crop pollinators and pollen deposition
Context: Maximising insect pollination of mass-flowering crops is a widely-discussed approach to sustainable agriculture. Management actions can target landscape-scale semi-natural habitat, cropping patterns or field-scale features, but little is known about their relative effectiveness. Objective: to test how landscape composition (area of mass-flowering crops and semi-natural habitat) and field-scale habitat (margins and hedges) affect pollinator species richness, abundance, and pollen deposition within crop fields. Methods: We surveyed all flower visitors (Diptera, Coleoptera and Hymenoptera) in oilseed rape fields and related them to landscape composition and field features. Flower visitors were classified as bees, non-bee pollinators and brassica specialists. Total pollen deposition by individual taxa was estimated using single visit pollen deposition on stigmas combined with insect abundance. Results: the area of mass-flowering crop had a negative effect on the species richness and abundance of bees in fields, but not other flower visitors. The area of semi-natural habitat in the surrounding landscape had a positive effect on bees, but was not as important as the area of mass-flowering crop. Taxonomic richness and abundance varied significantly between years for non-bee pollinators. Greater cover of mass-flowering crops surrounding fields had a negative effect on pollen deposition, but only when non-bee pollinator numbers were reduced. Conclusions: Management choices that result in landscape homogenisation, such as large areas of mass-flowering crops, may reduce pollination services by reducing the numbers of bees visiting fields. Non-bee insect pollinators may buffer these landscape effects on pollen deposition, and management to support their populations should be considered.
Abstract.
Knapp JL, Phillips BB, Clements J, Shaw RF, Osborne J (2020). Socio-psychological factors, beyond knowledge, predict people’s engagement with. pollinator conservation (dataset).
Knapp JL, Phillips BB, Clements J, Shaw RF, Osborne J (2020). Socio-psychological factors, beyond knowledge, predict people’s engagement with pollinator conservation. People and Nature
Herascu R (2020). The Effects of Landscape and Experience on the Navigation and Foraging Behaviour of Bumblebees, Bombus terrestris.
Abstract:
The Effects of Landscape and Experience on the Navigation and Foraging Behaviour of Bumblebees, Bombus terrestris
Bumblebees live in an environment where the spatial distribution of foraging resources is always changing. In order to keep track of such changes, bumblebees employ a variety of different navigation and foraging strategies. Although a substantial amount of research has investigated the different navigation and foraging behaviours of bumblebees, much less is known of the effects that landscape features have on bumblebee behaviour. In this thesis, a series of experiments were conducted in order to investigate the role that landscape features have on the navigation and foraging behaviour of Bombus terrestris and whether individuals’ experience influences such behaviour. A hedgerow situated next to the colony was not found to significantly shape the flight paths or foraging choices of naïve bumblebees. Homing success was investigated and used as a proxy for foraging range in different environment types. Both the release distance and the type of environment were found to have
a significant effect on the homing success of Bombus terrestris workers. Previous experience of the landscape was also found to significantly affect the time it took bumblebees to return to the colony (homing duration) as well as the likelihood of staying out overnight before returning to the colony. When focusing on the first five flights of a naïve bumblebee worker, experience was not found to significantly affect flight duration. Experience, however, significantly affected the weight of pollen foraged. The observed behaviour of bumblebee gynes provisioning their maternal colony with pollen was also investigated. The influx of pollen into the colony was found to affect this behaviour, suggesting that gynes will provision the maternal colony in response to its nutritional needs. The overall results are also discussed within the context of informing landscape management practices. The results presented in this thesis point to the critical role that factors such as the physical landscape and individual experience play in influencing bumblebee behaviour.
Abstract.
2019
Knapp JL, Osborne JL (2019). Cucurbits as a model system for crop pollination management.
Journal of Pollination Ecology,
25, 89-102.
Abstract:
Cucurbits as a model system for crop pollination management
Cucurbit crops have steadily increased in production over the last 50 years, particularly in Asia where pioneering technological advancements and genetic improvements have created new hybrid varieties. Generally, cucurbits are dependent on insect-pollination for fruit set and are popular species for pollination studies. This review systematically summarises pollination research conducted in the major food genera of cucurbits: Cucurbita, Cucumis, and Citrullus, to ask: 1) what are cucurbits' requirement for pollination and their most effective pollinators? and 2) Does pollinator management increase pollinator visitation to, and yield of, cucurbit crops? These accounts of cucurbit pollination demonstrate that wild bee species such as Bombus terrestris, B. impatiens and Eucera spp. were frequently able to fulfil the pollination requirements of multiple cucurbit species. However, pollinator behaviour, pollen deposition on stigmas, and pollinators' contribution to yield vary between cucurbit species and study site. Nonetheless, the provision of additional floral resources at both field and farm scales may help to encourage pollination of cucurbit species whilst supporting pollinators' nutritional requirements beyond those already provided by the cucurbit crop. Synthesising studies on cucurbits' requirement for pollination and how pollinators vary spatially and temporally in the landscape can extend beyond cucurbit systems to inform growers and pollination ecologists of other pollinator-dependent crop species wishing to maximise pollination services, species conservation; or both.
Abstract.
Horn J, Becher MA, Johst K, Kennedy PJ, Osborne JL, Radchuk V, Grimm V (2019). Honeybee colony performance affected by crop diversity and farmland structure: a modelling framework.
Coppinger CR, Ellender BR, Stanley DA, Osborne J (2019). Insights into the impacts of rural honey hunting in Zambia. African Journal of Ecology, 57(4), 610-614.
Woodcock BA, Garratt MPD, Powney GD, Shaw RF, Osborne JL, Soroka J, Lindström SAM, Stanley D, Ouvrard P, Edwards ME, et al (2019). Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield.
Nature Communications,
10(1).
Abstract:
Meta-analysis reveals that pollinator functional diversity and abundance enhance crop pollination and yield
© 2019, Crown. How insects promote crop pollination remains poorly understood in terms of the contribution of functional trait differences between species. We used meta-analyses to test for correlations between community abundance, species richness and functional trait metrics with oilseed rape yield, a globally important crop. While overall abundance is consistently important in predicting yield, functional divergence between species traits also showed a positive correlation. This result supports the complementarity hypothesis that pollination function is maintained by non-overlapping trait distributions. In artificially constructed communities (mesocosms), species richness is positively correlated with yield, although this effect is not seen under field conditions. As traits of the dominant species do not predict yield above that attributed to the effect of abundance alone, we find no evidence in support of the mass ratio hypothesis. Management practices increasing not just pollinator abundance, but also functional divergence, could benefit oilseed rape agriculture.
Abstract.
Phillips BB, Gaston KJ, Bullock J, Osborne JL (2019). Phillips et al (2019) "Road verges are pollinator hotspots in agricultural landscapes, but are diminished by heavy traffic and summer verge cutting" J Applied Ecology (dataset).
Abstract:
Phillips et al (2019) "Road verges are pollinator hotspots in agricultural landscapes, but are diminished by heavy traffic and summer verge cutting" J Applied Ecology (dataset)
Flower and pollinator communities were surveyed in 2018, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge, and the field interior were surveyed.
Abstract.
Knapp JL, Shaw RF, Osborne JL (2019). Pollinator visitation to mass-flowering courgette and co-flowering wild flowers: Implications for pollination and bee conservation on farms.
Basic and Applied Ecology,
34, 85-94.
Abstract:
Pollinator visitation to mass-flowering courgette and co-flowering wild flowers: Implications for pollination and bee conservation on farms
Managing the complex relationship between pollinators and their habitat requirements is of particular concern to growers of pollinator-dependent crop species, such as courgette (Cucurbita pepo). Naturally occurring wild flowers (i.e. agricultural weeds) offer a free, sustainable, and often underappreciated resource for pollinators, however, they may compete with crop flowers for visits. To understand the extent to which floral resources mediate pollinator visitation to courgette flowers and courgette fields, plant community and pollinator visitation data were collected at two spatial scales: field scale (in margins, and in the cropped area) and farm scale (500 m and 2000 m radii) for nine courgette fields across the UK. Apis mellifera (honeybees) and Bombus spp. (bumblebees) were the only pollinators observed to visit courgette flowers. Bumblebees were significantly more abundant on courgette flowers in fields with a greater species richness of wild flowers in the crop, whilst honeybees were significantly more abundant on courgette flowers in areas with less semi-natural habitat. For both honeybees and bumblebees, their abundance in field margins did not significantly reduce their abundance on courgette flowers, suggesting that wild flowers were not competing with courgette flowers for pollinator visitation. Although solitary bees were not observed to visit courgette flowers, their abundance and species richness in courgette fields were significantly greater with more semi-natural habitat and a greater species richness of wild flowers. Therefore, allowing uncultivated areas around the crop to be colonised by species-rich wild flowers is an effective way of boosting the abundance of bumblebees, which are important visitors to courgette flowers, as well as the abundance and species richness of solitary bees, thereby benefitting pollinator conservation.
Abstract.
Roberts B, Cox R, Osborne J (2019). Quantifying the relative predation pressure on bumblebee nests by the European badger (Meles meles) using artificial nests.
Abstract:
Quantifying the relative predation pressure on bumblebee nests by the European badger (Meles meles) using artificial nests
Bumblebee populations are declining. Factors that impact the size and success of colonies act either by limiting resource availability (bottom-up regulation) or by causing mortality e.g. pesticides, disease and possibly predation (top-down regulation). The impact of predation has not been quantified and so the current study used novel artificial nests as a proxy for wild bumblebee nests to quantify the relative predation pressure from badgers in two habitats: woodland and grassland, and at two nesting depths: surface and underground. Badgers occur across most parts of the UK, and are known to predate on bumblebee nests. We found that significantly more artificial nests (pots containing bumblebee nest material) were dug up compared to control pots (pots without bumblebee nest material). This shows that artificial nests have the potential to be used as a method to study the predation of bumblebee nests by badgers. In a location of high badger density, predation pressure was greater in woodland than grassland, whereas no difference was observed in relation to nest depth. Woodland and grassland are shared habitats between bumblebees and badgers and we suggest that higher predation may relate to activity and foraging behaviour of badgers in woodland compared to grassland. We discuss how badger predation in different habitats could impact different bumblebee species according to their nesting behaviours. Understanding the relative impact of badger predation on bumblebee colonies provides key information on how such top-down regulation affects bumblebee populations.
Abstract.
Phillips BB, Gaston KJ, Bullock JM, Osborne JL (2019). Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting.
Journal of Applied Ecology,
56(10), 2316-2327.
Abstract:
Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting
Supporting pollinators in agricultural landscapes is important for reversing their global decline. Road verges and hedges are used by pollinators for feeding and reproduction, but few studies consider entire pollinator communities, and it remains unclear how they are distributed across adjacent verges, hedges and fields, or how they are affected by traffic and verge cutting. We surveyed flowers and pollinators, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, we surveyed the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge and the field interior. Road verges and hedges had a much greater flower abundance, flower species richness and pollinator abundance than field interiors. Verge hedges had far less woody cover than field hedges, but greater flower species richness. There were fewer pollinators along verge edges (next to roads) than along verge centres (2–11 m from roads) and fewer pollinators in road verges next to busier roads. Road verges were generally cut once (in summer), and cuttings were never removed. There were substantially fewer flowers and pollinators in road verges that had been cut, even though surveys often took place many weeks after cutting. Synthesis and applications. Road verges and their associated hedges can provide hotspots of resources for pollinators in agricultural landscapes, but their capacity to do so is reduced by heavy traffic and summer verge cutting. We recommend that beneficial management for pollinators should prioritize wider road verges (at least 2 m wide), roads with less traffic, and areas away from the immediate vicinity of the road. Where possible, verge cutting should not be carried out during peak flowering times.
Abstract.
Roberts BR, Osborne JL (2019). Testing the efficacy of a thermal camera as a search tool for locating wild bumble bee nests.
Journal of Apicultural Research,
58(4), 494-500.
Abstract:
Testing the efficacy of a thermal camera as a search tool for locating wild bumble bee nests
Research into how bumble bee colonies respond to the stressors affecting their populations are currently studied in the laboratory using commercially reared Bombus terrestris colonies. Understanding how these stressors affect wild bumble bee colonies in the field would be a crucial step forward for the conservation of bumble bee species. Currently, visual cues are used to locate bumble bee nests, using human searchers looking for the worker nest traffic, but the limitations of this method mean that low numbers of nests are found and so a new method that looks to tackle these limitations is needed. Thermal cameras have been considered as a potential nest searching tool because they reduce the visual complexity of the environment by displaying a homogenized thermal landscape to the searcher. In this study, we compare the use of a thermal camera to human searches using two trials: (i) using inexperienced volunteers to search along the transect for a known bumble bee nest and (ii) using an experienced individual to search across a number of novel locations. We found thermal cameras are not a better nest detection technique than human searches, having low success rates across both trials. We discuss the limitations of thermal cameras as a technique and propose how the technology could be improved for future studies.
Abstract.
Roberts B (2019). The hidden ecology of bumblebees: using classical and new methods to explore nest searching, floral resources and badger predation.
Abstract:
The hidden ecology of bumblebees: using classical and new methods to explore nest searching, floral resources and badger predation
Bumblebees provide a crucial ecosystem service, and are experiencing worldwide declines due to a number of stressors, such as habitat loss and climate change. Populations are regulated through ‘bottom-up’ (resources) and ‘top-down’ (pesticides, disease and predation) processes. Bumblebees have been widely researched, but there are still aspects of their ecology which are understudied due to the difficulties associated with researching them. This is the case for nest locations and nest predation. This thesis aims to uncover some of these hidden aspects of bumblebee ecology, through the development and implementation of new techniques: thermal cameras as a tool to locate bumblebee nests (Chapter 3), artificial nests to study badger predation rates (Chapter 4 & 5), and the utilisation of model simulations to look at the potential combined impacts of badger predation and food availability on bumblebee populations (Chapter 5). Thermal cameras were found to be unsuccessful, due to their small viewing areas. However the artificial nest method was shown to be a successful way of studying the relative differences in predation rates between habitats and geographic locations, with high predation of bumblebee nests in areas of high badger densities. Model simulations also showed that under high badger predation rates a simulated bumblebee population produced significantly fewer hibernating queens, workers, and colonies. Thus, novel research tools were found to be a useful way of monitoring the effects of top-down and bottom-up effects on bumblebee populations.
Alongside this, classical field techniques were used to study the use of botanical gardens and semi-natural farmland habitats by nest searching queens, and the foraging resources they provide across the flight season (Chapter 2). Residential gardens have been shown to be beneficial habitats for bumblebees, especially in urban environments. In Chapter 2 botanical gardens are looked at in a rural setting, which has not been done previously. Botanical gardens were found to contain a high number of nest searching queens, and experienced a peak of spring floral resources. However semi-natural habitats in farmland provided higher levels of floral resources in early and late summer. Therefore these two habitats may be providing complementary floral resources to pollinators. These results are discussed in terms of the importance of habitat heterogeneity for supporting pollinator populations.
Abstract.
2018
Knapp J, Becher MA, Rankin C, Twiston-Davies G, Osborne JL (2018). Bombus terrestris in a mass‐flowering pollinator‐dependent
crop: a mutualistic relationship?. Ecology and Evolution
Becher MA, Twiston-Davies G, Penny TD, Goulson D, Rotheray EL, Osborne JL (2018). Bumble-BEEHAVE: a systems model for exploring multifactorial causes of bumblebee decline at individual, colony, population and community level.
Journal of Applied Ecology,
55(6), 2790-2801.
Abstract:
Bumble-BEEHAVE: a systems model for exploring multifactorial causes of bumblebee decline at individual, colony, population and community level
World-wide declines in pollinators, including bumblebees, are attributed to a multitude of stressors such as habitat loss, resource availability, emerging viruses and parasites, exposure to pesticides, and climate change, operating at various spatial and temporal scales. Disentangling individual and interacting effects of these stressors, and understanding their impact at the individual, colony and population level are a challenge for systems ecology. Empirical testing of all combinations and contexts is not feasible. A mechanistic multilevel systems model (individual-colony-population-community) is required to explore resilience mechanisms of populations and communities under stress. We present a model which can simulate the growth, behaviour and survival of six UK bumblebee species living in any mapped landscape. Bumble-BEEHAVE simulates, in an agent-based approach, the colony development of bumblebees in a realistic landscape to study how multiple stressors affect bee numbers and population dynamics. We provide extensive documentation, including sensitivity analysis and validation, based on data from literature. The model is freely available, has flexible settings and includes a user manual to ensure it can be used by researchers, farmers, policy-makers, NGOs or other interested parties. Model outcomes compare well with empirical data for individual foraging behaviour, colony growth and reproduction, and estimated nest densities. Simulating the impact of reproductive depression caused by pesticide exposure shows that the complex feedback mechanisms captured in this model predict higher colony resilience to stress than suggested by a previous, simpler model. Synthesis and applications. The Bumble-BEEHAVE model represents a significant step towards predicting bumblebee population dynamics in a spatially explicit way. It enables researchers to understand the individual and interacting effects of the multiple stressors affecting bumblebee survival and the feedback mechanisms that may buffer a colony against environmental stress, or indeed lead to spiralling colony collapse. The model can be used to aid the design of field experiments, for risk assessments, to inform conservation and farming decisions and for assigning bespoke management recommendations at a landscape scale.
Abstract.
Phillips BB, Shaw RF, Holland MJ, Fry EL, Bardgett RD, Bullock JM, Osborne JL (2018). Drought reduces floral resources for pollinators. Global Change Biology, 24, 3226-3235.
Pilgrim ES, Osborne J, Winter M (2018). Evaluating the multiple benefits of multi-layered agroforestry systems.
International Journal of Agricultural Management,
7(2), 4-16.
Abstract:
Evaluating the multiple benefits of multi-layered agroforestry systems
Globally, the contribution of own-growers' to food security is over-looked.We explore a novel temperate, own-growing, agroforestry method that originates from Britain; the forest garden. Inspired by ancient tropical multi-layered homegardens, forest gardens integrate nature and food production. Consequently, they have spread globally despitebeing little researched. We sub-sampled 51 British forest gardens described as: Mature (≥15 years old), Young (≤10 years old) or Mixed (Young forest garden with an experienced manager). Using a semi-structured telephone questionnaire, we characterise forest gardens as: diverse food systems containing on average 64.2 (±6.65) predominantly perennial plant species; spread over at least four layers. Typically, they are ≤0.8 ha; on sloping, low value agricultural land. Forest gardeners are principally motivated by environmental protection and a lifestyle that enhances well-being. Their diet is broadened by foraging wild plants and common garden species, considered a delicacy in other cultures; thereby reducing their reliance on environmentally challenging annual crops. Forest gardens, like homegardens, could deliver social, economic and environmental benefits. They also illustrate that exploring ancient cultures and techniques can provide ideas and solutions to our modern food conundrums. However, combing a holistic academic approach with forest and homegarden practitioner knowledge will enhance our understanding of their alternative crops.
Abstract.
Nicholls E, Botías C, Rotheray EL, Whitehorn P, David A, Fowler R, David T, Feltham H, Swain JL, Wells P, et al (2018). Monitoring Neonicotinoid Exposure for Bees in Rural and Peri-urban Areas of the U.K. during the Transition from Pre- to Post-moratorium.
Environ Sci Technol,
52(16), 9391-9402.
Abstract:
Monitoring Neonicotinoid Exposure for Bees in Rural and Peri-urban Areas of the U.K. during the Transition from Pre- to Post-moratorium.
Concerns regarding the impact of neonicotinoid exposure on bee populations recently led to an EU-wide moratorium on the use of certain neonicotinoids on flowering crops. Currently, evidence regarding the impact, if any, the moratorium has had on bees' exposure is limited. We sampled pollen and nectar from bumblebee colonies in rural and peri-urban habitats in three U.K. regions: Stirlingshire, Hertfordshire, and Sussex. Colonies were sampled over three years: prior to the ban (2013), during the initial implementation when some seed-treated winter-sown oilseed rape was still grown (2014), and following the ban (2015). To compare species-level differences, in 2014 only, honeybee colonies in rural habitats were also sampled. Over half of all samples were found to be contaminated ( n = 408), with thiamethoxam being the compound detected at the highest concentrations in honeybee- (up to 2.29 ng/g in nectar in 2014, median ≤ 0.1 ng/g, n = 79) and bumblebee-collected pollen and nectar (up to 38.77 ng/g in pollen in 2013, median ≤ 0.12 ng/g, n = 76). Honeybees were exposed to higher concentrations of neonicotinoids than bumblebees in 2014. While neonicotinoid exposure for rural bumblebees declined post-ban (2015), suggesting a positive impact of the moratorium, the risk of neonicotinoid exposure for bumblebees in peri-urban habitats remained largely the same between 2013 and 2015.
Abstract.
Author URL.
Kennedy PJ, Ford SM, Poidatz J, Thiery D, Osborne JL (2018). Searching for nests of the invasive Asian hornet (Vespa velutina) using radio-telemetry.
Communications Biology,
1Abstract:
Searching for nests of the invasive Asian hornet (Vespa velutina) using radio-telemetry
Asian hornets (Vespa velutina) are voracious predators of bees, and are the latest emerging threat to managed and wild pollinator populations in Europe. To prevent establishment or reduce the rate of spread of V. velutina, early detection and destruction of nests is considered the only option. Detection is difficult as their nests are well hidden and flying hornets are difficult to follow over long distances. We address this challenge by tracking individual V. velutina workers flying back to their nests using radio telemetry for the first time, finding five previously undiscovered nests, up to 1.33 km from hornet release points. Hornets can fly with 0.28 g tags if the tag:hornet ratio is less than 0.8. This method offers a step-change in options to tackle the spread of this invader, providing an efficient means of finding V. velutina nests in complex environments to manage this emerging threat to pollinators.
Full text:. http://www.nature.com/articles/s42003-018-0092-9
Abstract.
Phillips BB, Williams A, Shaw RF, Osborne JL (2018). Shared traits make flies and bees effective pollinators of oilseed rape (Brassica napus L.). Basic and Applied Ecology
Beadle K (2018). Understanding the molecular and biochemical basis of insecticide selectivity against solitary bee pollinator.
Abstract:
Understanding the molecular and biochemical basis of insecticide selectivity against solitary bee pollinator
Certain eusocial bee pollinators have been found to exhibit profound differences in their sensitivity to different chemical insecticides within the same class (e.g. the N-nitroguanidine neonicotinoid imidacloprid and the N-cyanoamidine thiacloprid). Recent work on honey bees and bumblebees has shown that this variation in sensitivity is due, at least in part, to differences in the capacity of cytochromes P450 belonging to the CYP9Q subfamily to detoxify different insecticides. The solitary red mason bee, Osmia bicornis, is the most economically important solitary pollinator in Europe, yet its sensitivity to insecticides is not well characterised. Topical insecticide bioassays revealed that like honey bees and bumblebees, O. bicornis exhibits significant differences in sensitivity to insecticides within the same class, demonstrated by a >2,000-fold difference in sensitivity to imidacloprid and thiacloprid. Radioligand competition assays revealed no significant differences in the binding affinity of imidacloprid and thiacloprid to nicotinic acetylcholine receptors (nAChRs) isolated from head membrane preparations, demonstrating that differences in the binding affinity of imidacloprid and thiacloprid for nAChRs does not explain the marked variation in bee sensitivity to these compounds. Furthermore, cuticular penetration assays revealed no difference in the rate of penetration of these insecticides. The differential sensitivity observed during toxicity bioassays was found to be greatly suppressed on addition of the P450 inhibitor, PBO, prior to thiacloprid application but not imidacloprid application, suggesting that P450s play a role in determining the sensitivity of O. bicornis to neonicotinoid insecticides.
Sequencing of the transcriptome and genome of O. bicornis along with the annotation of other bee genomes revealed that O. bicornis and most other solitary bee species lack the cyp9q subfamily. Subsequently, the most closely related O. bicornis P450s to this subfamily were selected as potential thiacloprid-detoxifying orthologs for further characterisation. Kinetic studies revealed that six of the recombinantly expressed P450s were able to metabolise both imidacloprid and thiacloprid. However, all of the catalytically active P450s displayed a greater affinity for thiacloprid compared to imidacloprid, which could enable its rapid metabolism before any detrimental effects can occur, explaining, at least in part, its comparatively low toxicity. The most effective neonicotinoid metaboliser was found to be CYP9BU1, which also has the capacity to metabolise a number of other insecticides, suggesting that it may be a key detoxification enzyme of O. bicornis. O. bicornis microsomes displayed substantial ability to metabolise the secondary plant metabolite nicotine and incubation of recombinant P450s with nicotine identified CYP6AQ55 as a major nicotine metabolising enzyme. Taken together these findings illustrate that the CYPome of O. bicornis contains P450s that can metabolise both natural and synthetic insecticides.
Insecticide-metabolising P450s were found to be highly expressed in the Malpighian tubules, a primary site of xenobiotic detoxification, and the brain of O. bicornis, which contains high concentrations of nAChRs. Exposure of O. bicornis to sublethal doses of either imidacloprid or thiacloprid did not induce the expression of any P450s, suggesting constitutive expression of insecticide-metabolising P450s provides protective effects.
The knowledge generated in this thesis can be leveraged to help avoid negative insecticide impacts on this important solitary bee pollinator and provide tools to aid the design of bee-safe insecticides.
Abstract.
2017
Knapp JL, Osborne JL (2017). Courgette Production: Pollination Demand, Supply, and Value. Journal of Economic Entomology, 110(5), 1973-1979.
Mauchline AL, Cook SM, Powell W, Chapman JW, Osborne JL (2017). Migratory flight behaviour of the pollen beetle Meligethes aeneus.
Pest Manag Sci,
73(6), 1076-1082.
Abstract:
Migratory flight behaviour of the pollen beetle Meligethes aeneus.
BACKGROUND: the field ecology of the pollen beetle Meligethes aeneus and its damaging effects on oilseed rape crops are well understood. However, the flight behaviour of M. aeneus, in particular the drivers for migratory movements across the landscape, is not well studied. We combined three established methodologies - suction traps, vertical-looking radar and high-altitude aerial netting - to demonstrate that M. aeneus flies at a range of altitudes at different points during its active season. RESULTS: By linking evidence of high-altitude mass migration with immigration of pollen beetles into oilseed rape fields, we were able to 'ground-truth' the results to characterise the seasonal movements of this pest across the landscape. CONCLUSION: We demonstrate that this novel combination of methodologies can advance our understanding of the population movements of pollen beetles and could provide an opportunity to develop predictive models to estimate the severity and timing of pest outbreaks. © 2017 the Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Abstract.
Author URL.
Rumkee JCO, Becher MA, Thorbek P, Osborne JL (2017). Modeling Effects of Honeybee Behaviors on the Distribution of Pesticide in Nectar within a Hive and Resultant in-Hive Exposure.
Environ Sci Technol,
51(12), 6908-6917.
Abstract:
Modeling Effects of Honeybee Behaviors on the Distribution of Pesticide in Nectar within a Hive and Resultant in-Hive Exposure.
Recently, the causes of honeybee colony losses have been intensely studied, showing that there are multiple stressors implicated in colony declines, one stressor being the exposure to pesticides. Measuring exposure of individual bees within a hive to pesticide is at least as difficult as assessing the potential exposure of foraging bees to pesticide. We present a model to explore how heterogeneity of pesticide distribution on a comb in the hive can be driven by worker behaviors. The model contains simplified behaviors to capture the extremes of possible heterogeneity of pesticide location/deposition within the hive to compare with exposure levels estimated by averaging values across the comb. When adults feed on nectar containing the average concentration of all pesticide brought into the hive on that particular day, it is likely representative of the worst-case exposure scenario. However, for larvae, clustering of pesticide in the comb can lead to higher exposure levels than taking an average concentration in some circumstances. The potential for extrapolating the model to risk assessment is discussed.
Abstract.
Author URL.
Carruthers JM, Cook SM, Wright GA, Osborne JL, Clark SJ, Haughton AJ (2017). Oilseed rape (Brassica napus) as a resource for farmland insect pollinators: quantifying floral traits in conventional varieties and breeding systems. GCB Bioenergy, 9, 1370-1379.
Rotheray EL, Osborne JL, Goulson D (2017). Quantifying the food requirements and effects of food stress on bumble bee colony development.
Journal of Apicultural Research,
56(3), 288-299.
Abstract:
Quantifying the food requirements and effects of food stress on bumble bee colony development
Agricultural intensification has led to a reduction in semi-natural areas and in the abundance of wild flowering plants, reducing the availability of floral resources upon which pollinating insects depend. This is widely accepted as one of the major drivers of pollinator declines, but few studies have directly addressed the effects of dietary restrictions on pollinator fitness. Here, we investigated the effects of restricting pollen and nectar supply on bumble bee (Bombus terrestris) colony growth, adult size and number. Colonies required up to 6 g pollen/1 g protein and 50 g sugar to establish a colony of 5 workers, and consumed in excess of 176 g pollen/31 g protein and 1,186 g sugar in their lifetime. Regardless of restrictions on pollen or nectar availability, colonies consumed a ratio of 1 g protein to ~43 g sugar, though free-flying colonies require proportionally more sugar to fuel foraging. Food-limited colonies from an early stage grew little with anything less than ad-lib nectar, while more-established colonies increased in weight even with low levels of nectar suggesting a shortage of resources in early spring may be most damaging to bumble bee colonies. Dietary restriction reduced the number of reproductives produced, but had variable effects on the size of workers and males. Nosema ceranae infection was included as a covariate in analyses and had a significant negative effect on colony growth. This study provides a base line for the developmental requirements of bumble bee colonies, and indicates the effects a resource deficit may have on their development and reproduction.
Abstract.
2016
Becher MA, Grimm V, Knapp J, Horn J, Twiston-Davies G, Osborne JL (2016). BEESCOUT: a model of bee scouting behaviour and a software tool for characterizing nectar/pollen landscapes for BEEHAVE.
Ecological Modelling,
340, 126-133.
Abstract:
BEESCOUT: a model of bee scouting behaviour and a software tool for characterizing nectar/pollen landscapes for BEEHAVE
Social bees are central place foragers collecting floral resources from the surrounding landscape, but little is known about the probability of a scouting bee finding a particular flower patch. We therefore developed a software tool, BEESCOUT, to theoretically examine how bees might explore a landscape and distribute their scouting activities over time and space. An image file can be imported, which is interpreted by the model as a “forage map” with certain colours representing certain crops or habitat types as specified by the user. BEESCOUT calculates the size and location of these potential food sources in that landscape relative to a bee colony. An individual-based model then determines the detection probabilities of the food patches by bees, based on parameter values gathered from the flight patterns of radar-tracked honeybees and bumblebees. Various “search modes” describe hypothetical search strategies for the long-range exploration of scouting bees. The resulting detection probabilities of forage patches can be used as input for the recently developed honeybee model BEEHAVE, to explore realistic scenarios of colony growth and death in response to different stressors. In example simulations, we find that detection probabilities for food sources close to the colony fit empirical data reasonably well. However, for food sources further away no empirical data are available to validate model output. The simulated detection probabilities depend largely on the bees’ search mode, and whether they exchange information about food source locations. Nevertheless, we show that landscape structure and connectivity of food sources can have a strong impact on the results. We believe that BEESCOUT is a valuable tool to better understand how landscape configurations and searching behaviour of bees affect detection probabilities of food sources. It can also guide the collection of relevant data and the design of experiments to close knowledge gaps, and provides a useful extension to the BEEHAVE honeybee model, enabling future users to explore how landscape structure and food availability affect the foraging decisions and patch visitation rates of the bees and, in consequence, to predict colony development and survival.
Abstract.
Gill RJ, Baldock KCR, Brown MJF, Cresswell JE, Dicks LV, Fountain MT, Garratt MPD, Gough LA, Heard MS, Holland JM, et al (2016). Chapter Four Protecting an Ecosystem Service Approaches to Understanding and Mitigating Threats to Wild Insect Pollinators. In (Ed) Ecosystem Services: from Biodiversity to Society, Part 2, 135-206.
Wells T, Wolf S, Nicholls E, Groll H, Lim KS, Clark SJ, Swain J, Osborne JL, Haughton AJ (2016). Flight performance of actively foraging honey bees is reduced by a common pathogen. Environmental Microbiology Reports
Wolf S, Nicholls E, Reynolds AM, Wells P, Lim KS, Paxton RJ, Osborne JL (2016). Optimal search patterns in honeybee orientation flights are robust against emerging infectious diseases.
Scientific Reports,
6Abstract:
Optimal search patterns in honeybee orientation flights are robust against emerging infectious diseases
© the Author(s) 2016. Lévy flights are scale-free (fractal) search patterns found in a wide range of animals. They can be an advantageous strategy promoting high encounter rates with rare cues that may indicate prey items, mating partners or navigational landmarks. The robustness of this behavioural strategy to ubiquitous threats to animal performance, such as pathogens, remains poorly understood. Using honeybees radar-tracked during their orientation flights in a novel landscape, we assess for the first time how two emerging infectious diseases (Nosema sp. and the Varroa-associated Deformed wing virus (DWV)) affect bees' behavioural performance and search strategy. Nosema infection, unlike DWV, affected the spatial scale of orientation flights, causing significantly shorter and more compact flights. However, in stark contrast to disease-dependent temporal fractals, we find the same prevalence of optimal Lévy flight characteristics (μ ≈ 2) in both healthy and infected bees. We discuss the ecological and evolutionary implications of these surprising insights, arguing that Lévy search patterns are an emergent property of fundamental characteristics of neuronal and sensory components of the decision-making process, making them robust against diverse physiological effects of pathogen infection and possibly other stressors.
Abstract.
Henry M, Becher MA, Osborne JL, Kennedy PJ, Aupinel P, Bretagnolle V, Brun F, Grimm V, Horn J, Requier F, et al (2016). Predictive systems models can help elucidate bee declines driven by multiple combined stressors. Apidologie
Gill RJ, Baldock KCR, Brown MJF, Cresswell JE, Dicks LV, Fountain MT, Garratt MPD, Gough LA, Heard MS, Holland JM, et al (2016). Protecting an Ecosystem Service: Approaches to Understanding and Mitigating Threats to Wild Insect Pollinators.
,
54, 135-206.
Abstract:
Protecting an Ecosystem Service: Approaches to Understanding and Mitigating Threats to Wild Insect Pollinators
Insect pollination constitutes an ecosystem service of global importance, providing significant economic and aesthetic benefits as well as cultural value to human society, alongside vital ecological processes in terrestrial ecosystems. It is therefore important to understand how insect pollinator populations and communities respond to rapidly changing environments if we are to maintain healthy and effective pollinator services. This chapter considers the importance of conserving pollinator diversity to maintain a suite of functional traits and provide a diverse set of pollinator services. We explore how we can better understand and mitigate the factors that threaten insect pollinator richness, placing our discussion within the context of populations in predominantly agricultural landscapes in addition to urban environments. We highlight a selection of important evidence gaps, with a number of complementary research steps that can be taken to better understand: (i) the stability of pollinator communities in different landscapes in order to provide diverse pollinator services; (ii) how we can study the drivers of population change to mitigate the effects and support stable sources of pollinator services and (iii) how we can manage habitats in complex landscapes to support insect pollinators and provide sustainable pollinator services for the future. We advocate a collaborative effort to gain higher quality abundance data to understand the stability of pollinator populations and predict future trends. In addition, for effective mitigation strategies to be adopted, researchers need to conduct rigorous field testing of outcomes under different landscape settings, acknowledge the needs of end-users when developing research proposals and consider effective methods of knowledge transfer to ensure effective uptake of actions. © 2016 Elsevier Ltd.
Abstract.
Knapp JL, Bartlett LJ, Osborne JL (2016). Re-evaluating strategies for pollinator-dependent crops: How useful is parthenocarpy?. Journal of Applied Ecology, 54(4), 1171-1179.
2015
Carvell C, Bourke AFG, Osborne JL, Heard MS (2015). Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales.
Basic and Applied Ecology,
16(6), 519-530.
Abstract:
Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales
Agri-environment schemes (AES) have been implemented across Europe, aiming to mitigate effects of habitat loss in agro-ecosystems for a range of declining species. These include pollinating insects such as bumblebees, for which positive effects of AES on abundance and species richness have been shown. However, there is a lack of evidence for effects of AES on reproduction of target species, at either local or landscape scales. We conducted a large-scale study across landscapes exhibiting a gradient of agricultural intensity to investigate the effects of a targeted flower mixture, sown in patches of three different sizes, on an index of the total biomass of bumblebee sexuals (males and queens) on replicated transects within each landscape. We used this index (MQ) as a measure of bumblebee reproduction. After controlling for floral density on transects, we found that MQ was significantly higher on sown flower patches than on conventionally managed control patches at local scales throughout the three-year study. While sown flower patches did not significantly increase MQ in surrounding landscapes, MQ was higher in landscapes surrounding larger (1. ha) than smaller (0.25. ha) sown patches. Our results suggest that, while responses of different bee species may vary depending on the plant species sown, targeted flower mixtures can enhance bumblebee reproduction by providing locally attractive forage resources to bumblebees of all castes and sexes from nests within foraging distance. If established at large enough scales, sown flower patches may lead to a detectable spill-over of reproductives into surrounding landscapes. Furthermore, effects of sown patches on MQ were moderated by landscape context, the strongest positive responses being detected at sites with high proportions of arable land. This supports previous findings that AES can deliver greater net benefits for pollinators in more intensively farmed landscapes.
Abstract.
Horn J, Becher MA, Kennedy PJ, Osborne JL, Grimm V (2015). Multiple stressors: using the honeybee model BEEHAVE to explore how spatial and temporal forage stress affects colony resilience. Oikos, 125(7), 1001-1016.
Rumkee JCO, Becher MA, Thorbek P, Kennedy PJ, Osborne JL (2015). Predicting Honeybee Colony Failure: Using the BEEHAVE Model to Simulate Colony Responses to Pesticides.
Environ Sci Technol,
49(21), 12879-12887.
Abstract:
Predicting Honeybee Colony Failure: Using the BEEHAVE Model to Simulate Colony Responses to Pesticides.
To simulate effects of pesticides on different honeybee (Apis mellifera L.) life stages, we used the BEEHAVE model to explore how increased mortalities of larvae, in-hive workers, and foragers, as well as reduced egg-laying rate, could impact colony dynamics over multiple years. Stresses were applied for 30 days, both as multiples of the modeled control mortality and as set percentage daily mortalities to assess the sensitivity of the modeled colony both to small fluctuations in mortality and periods of low to very high daily mortality. These stresses simulate stylized exposure of the different life stages to nectar and pollen contaminated with pesticide for 30 days. Increasing adult bee mortality had a much greater impact on colony survival than mortality of bee larvae or reduction in egg laying rate. Importantly, the seasonal timing of the imposed mortality affected the magnitude of the impact at colony level. In line with the LD50, we propose a new index of "lethal imposed stress": the LIS50 which indicates the level of stress on individuals that results in 50% colony mortality. This (or any LISx) is a comparative index for exploring the effects of different stressors at colony level in model simulations. While colony failure is not an acceptable protection goal, this index could be used to inform the setting of future regulatory protection goals.
Abstract.
Author URL.
2014
Becher MA, Grimm V, Thorbek P, Horn J, Kennedy PJ, Osborne JL (2014). BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure.
Journal of Applied Ecology,
51(2), 470-482.
Abstract:
BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure
Summary: a notable increase in failure of managed European honeybee Apis mellifera L. colonies has been reported in various regions in recent years. Although the underlying causes remain unclear, it is likely that a combination of stressors act together, particularly varroa mites and other pathogens, forage availability and potentially pesticides. It is experimentally challenging to address causality at the colony scale when multiple factors interact. In silico experiments offer a fast and cost-effective way to begin to address these challenges and inform experiments. However, none of the published bee models combine colony dynamics with foraging patterns and varroa dynamics. We have developed a honeybee model, BEEHAVE, which integrates colony dynamics, population dynamics of the varroa mite, epidemiology of varroa-transmitted viruses and allows foragers in an agent-based foraging model to collect food from a representation of a spatially explicit landscape. We describe the model, which is freely available online (www.beehave-model.net). Extensive sensitivity analyses and tests illustrate the model's robustness and realism. Simulation experiments with various combinations of stressors demonstrate, in simplified landscape settings, the model's potential: predicting colony dynamics and potential losses with and without varroa mites under different foraging conditions and under pesticide application. We also show how mitigation measures can be tested. Synthesis and applications. BEEHAVE offers a valuable tool for researchers to design and focus field experiments, for regulators to explore the relative importance of stressors to devise management and policy advice and for beekeepers to understand and predict varroa dynamics and effects of management interventions. We expect that scientists and stakeholders will find a variety of applications for BEEHAVE, stimulating further model development and the possible inclusion of other stressors of potential importance to honeybee colony dynamics. © 2014 the Authors. Journal of Applied Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.
Abstract.
Fürst MA, McMahon DP, Osborne JL, Paxton RJ, Brown MJF (2014). Disease associations between honeybees and bumblebees as a threat to wild pollinators.
Nature,
506(7488), 364-366.
Abstract:
Disease associations between honeybees and bumblebees as a threat to wild pollinators.
Emerging infectious diseases (EIDs) pose a risk to human welfare, both directly and indirectly, by affecting managed livestock and wildlife that provide valuable resources and ecosystem services, such as the pollination of crops. Honeybees (Apis mellifera), the prevailing managed insect crop pollinator, suffer from a range of emerging and exotic high-impact pathogens, and population maintenance requires active management by beekeepers to control them. Wild pollinators such as bumblebees (Bombus spp.) are in global decline, one cause of which may be pathogen spillover from managed pollinators like honeybees or commercial colonies of bumblebees. Here we use a combination of infection experiments and landscape-scale field data to show that honeybee EIDs are indeed widespread infectious agents within the pollinator assemblage. The prevalence of deformed wing virus (DWV) and the exotic parasite Nosema ceranae in honeybees and bumblebees is linked; as honeybees have higher DWV prevalence, and sympatric bumblebees and honeybees are infected by the same DWV strains, Apis is the likely source of at least one major EID in wild pollinators. Lessons learned from vertebrates highlight the need for increased pathogen control in managed bee species to maintain wild pollinators, as declines in native pollinators may be caused by interspecies pathogen transmission originating from managed pollinators.
Abstract.
Author URL.
Grimm V, Becher MA, Kennedy P, Thorbek P, Osborne J (2014). Ecological Modeling for Pesticide Risk Assessment for Honey Bees and Other Pollinators. In (Ed)
Pesticide Risk Assessment for Pollinators, 149-162.
Abstract:
Ecological Modeling for Pesticide Risk Assessment for Honey Bees and Other Pollinators
Abstract.
Carvell C, Bourke AFG, Osborne JL, Heard MS (2014). Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales.
Basic and Applied EcologyAbstract:
Effects of an agri-environment scheme on bumblebee reproduction at local and landscape scales
Agri-environment schemes (AES) have been implemented across Europe, aiming to mitigate effects of habitat loss in agro-ecosystems for a range of declining species. These include pollinating insects such as bumblebees, for which positive effects of AES on abundance and species richness have been shown. However, there is a lack of evidence for effects of AES on reproduction of target species, at either local or landscape scales. We conducted a large-scale study across landscapes exhibiting a gradient of agricultural intensity to investigate the effects of a targeted flower mixture, sown in patches of three different sizes, on an index of the total biomass of bumblebee sexuals (males and queens) on replicated transects within each landscape. We used this index (MQ) as a measure of bumblebee reproduction. After controlling for floral density on transects, we found that MQ was significantly higher on sown flower patches than on conventionally managed control patches at local scales throughout the three-year study. While sown flower patches did not significantly increase MQ in surrounding landscapes, MQ was higher in landscapes surrounding larger (1. ha) than smaller (0.25. ha) sown patches. Our results suggest that, while responses of different bee species may vary depending on the plant species sown, targeted flower mixtures can enhance bumblebee reproduction by providing locally attractive forage resources to bumblebees of all castes and sexes from nests within foraging distance. If established at large enough scales, sown flower patches may lead to a detectable spill-over of reproductives into surrounding landscapes. Furthermore, effects of sown patches on MQ were moderated by landscape context, the strongest positive responses being detected at sites with high proportions of arable land. This supports previous findings that AES can deliver greater net benefits for pollinators in more intensively farmed landscapes. Agrar-Umweltprogramme (AES) sind in ganz Europa eingerichtet worden mit dem Ziel, die Auswirkungen von Habitatverlusten in Agrarökosystemen für eine Reihe von zurückgehenden Arten zu mildern. Hierzu gehören Bestäuberinsekten wie z.B. Hummeln, für die positive Effekte durch AES auf Abundanz und Artenreichtum gezeigt werden konnten. Indessen mangelt es an Befunden zum Effekt von AES auf die Reproduktion von Zielarten auf der lokalen oder Landschafts-Skala. Wir führten eine großräumige Untersuchung in Landschaften, die einen Gradienten landwirtschaftlicher Intensität darstellten, durch, um den Effekt einer gezielt zusammengestellten Saatmischung, die auf Flächen unterschiedlicher Größe ausgesät wurde, auf einen Index der Gesamtbiomasse der Geschlechtstiere von Hummeln (Männchen und Königinnen) zu erkunden, indem wir replizierte Transekte in jeder Landschaft absuchten. Wir benutzten diesen Index (MQ) als ein Maß für die Reproduktion der Hummeln. Nach Kontrolle d er Blütendichte auf den Transekten fanden wir, dass auf der lokalen Skala MQ während der dreijährigen Untersuchungszeit auf den eingesäten Blühflächen signifikant höher war als auf konventionell bewirtschafteten Kontrollflächen. Während eingesäte Blühflächen den MQ-Index in der umgebenden Landschaft nicht signifikant erhöhten, war MQ in Landschaften, die große (1. ha) Blühflächen umgaben, höher als in Landschaften, die kleinere (0.25. ha) Blühflächen umgaben. Unsere Ergebnisse legen nahe, dass, während die Reaktionen unterschiedlicher Bienenarten in Abhängigkeit von den ausgesäten Arten unterschiedlich ausfallen können, zielorientierte Saatmischungen die Reproduktion von Hummeln steigern können, indem allen Kasten und Geschlechtern aus Nestern in Sammelentfernung lokal attraktive Nahrungsressourcen angeboten werden. Wenn sie in ausreichend großem Maßstab eingerichtet werden, können Blühflächen zu einem merklichen spill-over von reproduzierenden Individuen in die um gebende Landschaft führen.Desweiteren wurden die Effekte der Blühflächen auf MQ durch den Landschaftskontext vermittelt, wobei die am stärksten positiven Reaktionen in Landschaften mit hohem Anteil von Agrarflächen gefunden wurden. Dies unterstützt frühere Befunde, nach denen AES den größeren Netto-Nutzen für Bestäuber in intensiver bewirtschafteten Landschaften erbringen kann.
Abstract.
Wolf S, McMahon DP, Lim KS, Pull CD, Clark SJ, Paxton RJ, Osborne JL (2014). So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees.
PLoS One,
9(8).
Abstract:
So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees.
Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen--Nosema ceranae (Microsporidia)--on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed.
Abstract.
Author URL.
2013
Mauchline AL, Cook SM, Powell W, Osborne JL (2013). Effects of non-host plant odour on Meligethes aeneus during immigration to oilseed rape.
Entomologia Experimentalis et Applicata,
146(3), 313-320.
Abstract:
Effects of non-host plant odour on Meligethes aeneus during immigration to oilseed rape
The use of semiochemicals for the manipulation of the pollen beetle, Meliethes aeneus (Fabricius) (Coleoptera: Nitidulidae), is being investigated for potential incorporation into a push-pull strategy for this pest, which damages oilseed rape, Brassica napus L. (Brassicaceae), throughout Europe. Previous laboratory behavioural studies using volatiles from non-host plants showed that M. aeneus is repelled by the odour of lavender, Lavendula angustifolia Mill. (Lamiaceae), essential oil. This article reports on semi-field and field trials to investigate this behaviour under more realistic conditions. Semi-field experiments were conducted to assess the relative importance of olfaction at different points in host location behaviour by M. aeneus. The results showed that oilseed rape plants treated with lavender odour were less colonised by M. aeneus in comparison with an untreated control, but that the treatment effect was much reduced if the lavender odour was applied after colonisation. The field experiment demonstrated that lavender odour caused a significant reduction in the number of adult M. aeneus infesting the oilseed rape plants in the treatment plots compared to the control plots. Overall, these findings are very encouraging for the future development of a push-pull pest control system. © 2013 the Netherlands Entomological Society.
Abstract.
Dicks LV, Abrahams A, Atkinson J, Biesmeijer J, Bourn N, Brown C, Brown MJF, Carvell C, Connolly C, Cresswell JE, et al (2013). Identifying key knowledge needs for evidence-based conservation of wild insect pollinators: a collaborative cross-sectoral exercise.
Insect Conservation and Diversity,
6(3), 435-446.
Abstract:
Identifying key knowledge needs for evidence-based conservation of wild insect pollinators: a collaborative cross-sectoral exercise
In response to evidence of insect pollinator declines, organisations in many sectors, including the food and farming industry, are investing in pollinator conservation. They are keen to ensure that their efforts use the best available science. We convened a group of 32 'conservation practitioners' with an active interest in pollinators and 16 insect pollinator scientists. The conservation practitioners include representatives from UK industry (including retail), environmental non-government organisations and nature conservation agencies. We collaboratively developed a long list of 246 knowledge needs relating to conservation of wild insect pollinators in the UK. We refined and selected the most important knowledge needs, through a three-stage process of voting and scoring, including discussions of each need at a workshop. We present the top 35 knowledge needs as scored by conservation practitioners or scientists. We find general agreement in priorities identified by these two groups. The priority knowledge needs will structure ongoing work to make science accessible to practitioners, and help to guide future science policy and funding. Understanding the economic benefits of crop pollination, basic pollinator ecology and impacts of pesticides on wild pollinators emerge strongly as priorities, as well as a need to monitor floral resources in the landscape. © 2012 the Royal Entomological Society.
Abstract.
Becher MA, Osborne JL, Thorbek P, Kennedy PJ, Grimm V (2013). REVIEW: Towards a systems approach for understanding honeybee decline: a stocktaking and synthesis of existing models.
JOURNAL OF APPLIED ECOLOGY,
50(4), 868-880.
Author URL.
Osborne JL, Smith A, Clark SJ, Reynolds DR, Barron MC, Lim KS, Reynolds AM (2013). The ontogeny of bumblebee flight trajectories: from naïve explorers to experienced foragers.
PLoS One,
8(11).
Abstract:
The ontogeny of bumblebee flight trajectories: from naïve explorers to experienced foragers.
Understanding strategies used by animals to explore their landscape is essential to predict how they exploit patchy resources, and consequently how they are likely to respond to changes in resource distribution. Social bees provide a good model for this and, whilst there are published descriptions of their behaviour on initial learning flights close to the colony, it is still unclear how bees find floral resources over hundreds of metres and how these flights become directed foraging trips. We investigated the spatial ecology of exploration by radar tracking bumblebees, and comparing the flight trajectories of bees with differing experience. The bees left the colony within a day or two of eclosion and flew in complex loops of ever-increasing size around the colony, exhibiting Lévy-flight characteristics constituting an optimal searching strategy. This mathematical pattern can be used to predict how animals exploring individually might exploit a patchy landscape. The bees' groundspeed, maximum displacement from the nest and total distance travelled on a trip increased significantly with experience. More experienced bees flew direct paths, predominantly flying upwind on their outward trips although forage was available in all directions. The flights differed from those of naïve honeybees: they occurred at an earlier age, showed more complex looping, and resulted in earlier returns of pollen to the colony. In summary bumblebees learn to find home and food rapidly, though phases of orientation, learning and searching were not easily separable, suggesting some multi-tasking.
Abstract.
Author URL.
Vanbergen AJ, Initiative TIP (2013). Threats to an ecosystem service: pressures on pollinators. Frontiers in Ecology and the Environment, 11(5), 251-259.
Becher MA, Osborne JL, Thorbek P, Kennedy PJ, Grimm V (2013). Towards a systems approach for understanding honeybee decline: a stocktaking and synthesis of existing models.
Journal of Applied Ecology,
50(4), 868-880.
Abstract:
Towards a systems approach for understanding honeybee decline: a stocktaking and synthesis of existing models
The health of managed and wild honeybee colonies appears to have declined substantially in Europe and the United States over the last decade. Sustainability of honeybee colonies is important not only for honey production, but also for pollination of crops and wild plants alongside other insect pollinators. A combination of causal factors, including parasites, pathogens, land use changes and pesticide usage, are cited as responsible for the increased colony mortality. However, despite detailed knowledge of the behaviour of honeybees and their colonies, there are no suitable tools to explore the resilience mechanisms of this complex system under stress. Empirically testing all combinations of stressors in a systematic fashion is not feasible. We therefore suggest a cross-level systems approach, based on mechanistic modelling, to investigate the impacts of (and interactions between) colony and land management. We review existing honeybee models that are relevant to examining the effects of different stressors on colony growth and survival. Most of these models describe honeybee colony dynamics, foraging behaviour or honeybee - varroa mite - virus interactions. We found that many, but not all, processes within honeybee colonies, epidemiology and foraging are well understood and described in the models, but there is no model that couples in-hive dynamics and pathology with foraging dynamics in realistic landscapes. Synthesis and applications. We describe how a new integrated model could be built to simulate multifactorial impacts on the honeybee colony system, using building blocks from the reviewed models. The development of such a tool would not only highlight empirical research priorities but also provide an important forecasting tool for policy makers and beekeepers, and we list examples of relevant applications to bee disease and landscape management decisions. We describe how a new integrated model could be built to simulate multifactorial impacts on the honeybee colony system, using building blocks from the reviewed models. The development of such a tool would not only highlight empirical research priorities but also provide an important forecasting tool for policy makers and beekeepers, and we list examples of relevant applications to bee disease and landscape management decisions. © 2013 British Ecological Society.
Abstract.
Becher MA, Osborne JL, Thorbek P, Kennedy PJ, Grimm V (2013). Towards a systems approach for understanding honeybee decline: a stocktaking and synthesis of existing models. Journal of Applied Ecology
Lihoreau M, Raine NE, Reynolds AM, Stelzer RJ, Lim KS, Smith AD, Osborne JL, Chittka L (2013). Unravelling the mechanisms of trapline foraging in bees. Communicative & Integrative Biology, 6(1).
2012
Bull JC, Ryabov EV, Prince G, Mead A, Zhang C, Baxter LA, Pell JK, Osborne JL, Chandler D (2012). A Strong Immune Response in Young Adult Honeybees Masks Their Increased Susceptibility to Infection Compared to Older Bees.
PLOS PATHOGENS,
8(12).
Author URL.
Osborne JL (2012). Ecology: Bumblebees and pesticides.
Nature,
491(7422), 43-45.
Author URL.
Dicks LV, Abrahams A, Atkinson J, Biesmeijer J, Bourn N, Brown C, Brown MJ, Carvell C, Connolly C, Cresswell JE, et al (2012). Identifying key knowledge needs for evidence-based conservation of wild insect pollinators: a collaborative cross-sectoral exercise. Insect Conservation and Diversity
Lihoreau M, Raine NE, Reynolds AM, Stelzer RJ, Lim KS, Smith AD, Osborne JL, Chittka L (2012). Radar Tracking and Motion-Sensitive Cameras on Flowers Reveal the Development of Pollinator Multi-Destination Routes over Large Spatial Scales.
PLoS Biology,
10(9).
Abstract:
Radar Tracking and Motion-Sensitive Cameras on Flowers Reveal the Development of Pollinator Multi-Destination Routes over Large Spatial Scales
Central place foragers, such as pollinating bees, typically develop circuits (traplines) to visit multiple foraging sites in a manner that minimizes overall travel distance. Despite being taxonomically widespread, these routing behaviours remain poorly understood due to the difficulty of tracking the foraging history of animals in the wild. Here we examine how bumblebees (Bombus terrestris) develop and optimise traplines over large spatial scales by setting up an array of five artificial flowers arranged in a regular pentagon (50 m side length) and fitted with motion-sensitive video cameras to determine the sequence of visitation. Stable traplines that linked together all the flowers in an optimal sequence were typically established after a bee made 26 foraging bouts, during which time only about 20 of the 120 possible routes were tried. Radar tracking of selected flights revealed a dramatic decrease by 80% (ca. 1500 m) of the total travel distance between the first and the last foraging bout. When a flower was removed and replaced by a more distant one, bees engaged in localised search flights, a strategy that can facilitate the discovery of a new flower and its integration into a novel optimal trapline. Based on these observations, we developed and tested an iterative improvement heuristic to capture how bees could learn and refine their routes each time a shorter route is found. Our findings suggest that complex dynamic routing problems can be solved by small-brained animals using simple learning heuristics, without the need for a cognitive map. © 2012 Lihoreau et al.
Abstract.
Lye GC, Osborne JL, Park KJ, Goulson D (2012). Using citizen science to monitor Bombus populations in the UK: Nesting ecology and relative abundance in the urban environment.
Journal of Insect Conservation,
16(5), 697-707.
Abstract:
Using citizen science to monitor Bombus populations in the UK: Nesting ecology and relative abundance in the urban environment
Citizen science can provide a valuable tool for collecting large quantities of ecological data over a larger geographic area than would otherwise be possible. Here, data were collected on 1,022 bumblebee nests by means of a public survey in which participants were asked to record attributes of bumblebee nests discovered in their gardens. All commonly reported species appeared to be generalist in their nest site selection and though species-specific differences in nest site choice were evident, there was a high degree of overlap in nesting habitat between most species. There was little evidence supporting the hypothesis that bumblebees tend to nest in the same site in consecutive years. A comparison of the contributions made by different species to the total nests reported in this and previous similar surveys suggests that the common bumblebee species Bombus pascuorum may have declined over the past 20 years relative to other species, comprising ~21% of colonies discovered in a survey conducted in 1989-1991, but just 8-9% of colonies in 2007-2009. This was accompanied by a reduction in the proportion of nests on the ground surface (the preferred position of this species). This is the first quantitative evidence of potential declines in the one of the UK's 'big six' common bumblebee species. © 2011 Springer Science+Business Media B.V.
Abstract.
2011
Carvell C, Osborne JL, Bourke AFG, Freeman SN, Pywell RF, Heard MS (2011). Bumble bee species' responses to a targeted conservation measure depend on landscape context and habitat quality.
Ecological Applications,
21(5), 1760-1771.
Abstract:
Bumble bee species' responses to a targeted conservation measure depend on landscape context and habitat quality
The global decline of insect pollinators, especially bees, is cause for concern, and there is an urgent need for cost-effective conservation measures in agricultural landscapes. While landscape context and habitat quality are known to influence species richness and abundance of bees, there is a lack of evidence from manipulative field experiments on bees' responses to adaptive management across differently structured landscapes. We present the results of a large-scale study that investigated the effects of a targeted agri-environment scheme (AES) on bumble bees (Bombus spp.) over three years in the United Kingdom. Forage patches of different sizes were sown with a conservation flower mixture across eight sites covering a broad range of agricultural land use types. Species richness and worker densities (especially of the longer-tongued Bombus species for which the mixture was targeted) were significantly higher on sown forage patches than on existing non-crop control habitats throughout the three-year study, but the strength of this response depended on both the proportions of arable land and abundance of herbaceous forb species in the surrounding landscape. The size of sown patches also affected worker density, with smaller patches (0.25 ha) attracting higher densities of some species than larger patches (1.0 ha). Our models show that a targeted AES can deliver greater net benefits in more intensively farmed areas, in terms of the number and species richness of bumble bees supported, than in heterogeneous landscapes where other foraging habitats exist. These findings serve to strengthen the evidence base for extending agri-environment schemes to boost declining pollinator populations to a larger number of agricultural landscapes across the globe. © 2011 by the Ecological Society of America.
Abstract.
Lye GC, Jennings SN, Osborne JL, Goulson D (2011). Impacts of the use of nonnative commercial bumble bees for pollinator supplementation in raspberry.
Journal of Economic Entomology,
104(1), 107-114.
Abstract:
Impacts of the use of nonnative commercial bumble bees for pollinator supplementation in raspberry
Evidence for pollinator declines has led to concern that inadequate pollination services may limit crop yields. The global trade in commercial bumble bee (Bombus spp.) colonies provides pollination services for both glasshouse and open-field crops. For example, in the United Kingdom, commercial colonies of nonnative subspecies of the bumble bee Bombus terrestris L. imported from mainland Europe are widely used for the pollination of raspberries, Rubus idaeus L. The extent to which these commercial colonies supplement the services provided by wild pollinators has not been formally quantified and the impact of commercial bumble bees on native bees visiting the crop is unknown. Here, the impacts of allowing commercially available bumble bee colonies to forage on raspberry canes are assessed in terms of the yield of marketable fruit produced and the pollinator communities found foraging on raspberry flowers. No differences were found in the abundance, diversity, or composition of social bee species observed visiting raspberry flowers when commercial bumble bees were deployed compared with when they were absent. However, weight of marketable raspberries produced increased when commercial bees were present, indicating that wild pollinator services alone are inadequate for attaining maximum yields. The findings of the study suggests that proportional yield increases associated with deployment of commercial colonies may be small, but that nevertheless, investment in commercial colonies for raspberry pollination could produce very significant increases in net profit for the grower. Given potential environmental risks associated with the importation of nonnative bumble bees, the development of alternative solutions to the pollination deficit in raspberry crops in the United Kingdom may be beneficial. © 2011 Entomological Society of America.
Abstract.
Lye GC, Osborne JL, Park KJ, Goulson D (2011). Using citizen science to monitor Bombus populations in the UK: nesting ecology and relative abundance in the urban environment. Journal of Insect Conservation, 1-11.
2010
Goulson D, Lepais O, O'Connor S, Osborne JL, Sanderson RA, Cussans J, Goffe L, Darvill B (2010). Effects of land use at a landscape scale on bumblebee nest density and survival.
Journal of Applied Ecology,
47(6), 1207-1215.
Abstract:
Effects of land use at a landscape scale on bumblebee nest density and survival
1. We have little idea how landscape-scale factors influence the success of wild bumblebee nests over time. Here for the first time we use molecular markers to estimate within-season changes in the numbers of nests. 2. Workers of two bumblebee species were sampled in an arable landscape in late May-June and late July-August, and the numbers of nests represented in each sample were estimated. We compare the methods available to estimate nest number from such samples and conclude that methods which allow for heterogeneity in the probability of capture of nests provide the best fit to our data. Changes in numbers of nests at the two time points were used to infer nest survival. 3. The two bee species appeared to differ markedly in survival over time, with estimates of 45% of nests surviving for Bombus lapidarius and 91% for B. pascuorum. However, our data suggest that the foraging range of B. pascuorum may be greater in late season, which would lead us to overestimate nest survival in this species. Differential survival may also reflect differences in phenology between the two species. 4. The land use class which had the most consistent effects on nest number and survival was gardens; for B. lapidarius, the area of gardens within a 750 and 1000 m radius positively influenced nest survival, while for B. pascuorum, the number of nests in late samples was higher at sites with more gardens within a 500 and 750-m radius. For B. pascuorum, the area of grassland within a 250 and 500-m radius also positively influenced nest number in late samples, probably because this is the preferred nesting habitat for this species. 5. The importance of gardens is in accordance with previous studies which suggest that they now provide a stronghold for bumblebees in an otherwise impoverished agricultural environment; furthermore, our data suggest that the positive influence of gardens on bumblebee populations can spill over at least 1 km into surrounding farmland. 6. Synthesis and applications. The substantial effects that even small areas of local resources such as rough grassland or clover leys can have on bumblebee nest numbers and survival is of clear relevance for the design of pollinator management strategies. © 2010 the Authors. Journal compilation © 2010 British Ecological Society.
Abstract.
Lepais O, Darvill B, O'Connor S, Osborne JL, Sanderson RA, Cussans J, Goffe L, Goulson D (2010). Estimation of bumblebee queen dispersal distances using sibship reconstruction method.
Molecular Ecology,
19(4), 819-831.
Abstract:
Estimation of bumblebee queen dispersal distances using sibship reconstruction method
Dispersal ability is a key determinant of the propensity of an organism to cope with habitat fragmentation and climate change. Here we quantify queen dispersal in two common bumblebee species in an arable landscape. Dispersal was measured by taking DNA samples from workers in the spring and summer, and from queens in the following spring, at 14 sites across a landscape. The queens captured in the spring must be full sisters of workers that were foraging in the previous year. A range of sibship reconstruction methods were compared using simulated data sets including or no genotyping errors. The program Colony gave the most accurate reconstruction and was used for our analysis of queen dispersal. Comparison of queen dispersion with worker foraging distances was used to take into account an expected low level of false identification of sister pairs which might otherwise lead to overestimates of dispersal. Our data show that Bombus pascuorum and B. lapidarius queens can disperse by at least 3 and 5 km, respectively. These estimates are consistent with inferences drawn from studies of population structuring in common and rare bumblebee species, and suggest that regular gene flow over several kilometres due to queen dispersal are likely to be sufficient to maintain genetic cohesion of ubiquitous species over large spatial scales whereas rare bumblebee species appear unable to regularly disperse over distances greater than 10 km. Our results have clear implications for conservation strategies for this important pollinator group, particularly when attempting to conserve fragmented populations. © 2010 Blackwell Publishing Ltd.
Abstract.
Jacobs JH, Clark SJ, Denholm I, Goulson D, Stoate C, Osborne JL (2010). Pollinator effectiveness and fruit set in common ivy, Hedera helix (Araliaceae).
Arthropod-Plant Interactions,
4(1), 19-28.
Abstract:
Pollinator effectiveness and fruit set in common ivy, Hedera helix (Araliaceae)
Flowers of common ivy (Hedera helix L.) provide late season pollen and nectar for several insect groups, and its fruits are a winter and spring food source for frugivorous birds. Ivy benefits from insect pollination in order to set fruit, but it is unknown which flower-visiting insects are the most effective pollinators. Our observations suggest that Vespula wasps are potentially the most effective pollinators since they were frequent visitors, had relatively fast foraging rates, carried large numbers of pollen grains on their bodies and had the highest 'Pollination potential PP index' score (a measure of pollinator effectiveness) of all the insect groups examined. There was also a positive linear relationship between the proportion of ivy flowers that set fruit and wasp foraging activity in 0.5m2 quadrats. Visits by Vespula wasps may therefore be important for ensuring a supply of ivy fruits for birds. © Springer Science+Business Media B.V. 2009.
Abstract.
Cussans J, Goulson D, Sanderson R, Goffe L, Darvill B, Osborne JL (2010). Two bee-pollinated plant species show higher seed production when grown in gardens compared to arable farmland.
PLoS One,
5(7).
Abstract:
Two bee-pollinated plant species show higher seed production when grown in gardens compared to arable farmland.
BACKGROUND: Insect pollinator abundance, in particular that of bees, has been shown to be high where there is a super-abundance of floral resources; for example in association with mass-flowering crops and also in gardens where flowering plants are often densely planted. Since land management affects pollinator numbers, it is also likely to affect the resultant pollination of plants growing in these habitats. We hypothesised that the seed or fruit set of two plant species, typically pollinated by bumblebees and/or honeybees might respond in one of two ways: 1) pollination success could be reduced when growing in a floriferous environment, via competition for pollinators, or 2) pollination success could be enhanced because of increased pollinator abundance in the vicinity. METHODOLOGY/PRINCIPAL FINDINGS: We compared the pollination success of experimental plants of Glechoma hederacea L. and Lotus corniculatus L. growing in gardens and arable farmland. On the farms, the plants were placed either next to a mass-flowering crop (oilseed rape, Brassica napus L. or field beans, Vicia faba L.) or next to a cereal crop (wheat, Triticum spp.). Seed set of G. hederacea and fruit set of L. corniculatus were significantly higher in gardens compared to arable farmland. There was no significant difference in pollination success of G. hederacea when grown next to different crops, but for L. corniculatus, fruit set was higher in the plants growing next to oilseed rape when the crop was in flower. CONCLUSIONS/SIGNIFICANCE: the results show that pollination services can limit fruit set of wild plants in arable farmland, but there is some evidence that the presence of a flowering crop can facilitate their pollination (depending on species and season). We have also demonstrated that gardens are not only beneficial to pollinators, but also to the process of pollination.
Abstract.
Author URL.
2009
Lye G, Park K, Osborne J, Holland J, Goulson D (2009). Assessing the value of Rural Stewardship schemes for providing foraging resources and nesting habitat for bumblebee queens (Hymenoptera: Apidae).
Biological Conservation,
142(10), 2023-2032.
Abstract:
Assessing the value of Rural Stewardship schemes for providing foraging resources and nesting habitat for bumblebee queens (Hymenoptera: Apidae)
Bumblebees (Bombus spp.) play a key role within agricultural systems as pollinators of crops and wild flowers. However, this taxon has suffered severe declines as a result of agricultural intensification. Conservation efforts largely focus on providing forage resources for bumblebees through the summer, but providing suitable habitat during the period of nest foundation in early spring could be a more effective method of boosting local bumblebee populations. This study assesses the attractiveness of three different farmland habitat types (hedgerow, field margin and grassland), and the relative merits of respective land management prescriptions under the Scottish Rural Stewardship scheme to nest site searching and foraging bumblebee queens during the period of queen emergence and colony foundation. Hedgerows were the least attractive habitat type to spring queens. Rural Stewardship species-rich grassland comprised a complex vegetation structure attracting nest site searching queens, whilst grassland that had been abandoned allowing natural regeneration contained more flowers, attracting foraging queens. Field margin habitats were the most attractive habitat type, and Rural Stewardship field margins attracted both nest site searching and foraging queens at relatively high densities. This management option consisted of a sown grass mix, giving rise to the complex vegetation structure preferred by nest site searching queens, but regular disturbance allowed invasion by early flowering bumblebee forage plants. These findings suggest that it should be possible to develop simple combined management strategies to provide both suitable nesting sites and spring forage resources on farmland, promoting bumblebee colony foundation and therefore abundance in the agricultural environment. © 2009.
Abstract.
Knight ME, Osborne JL, Sanderson RA, Hale RJ, Martin AP, Goulson D (2009). Bumblebee nest density and the scale of available forage in arable landscapes.
INSECT CONSERVATION AND DIVERSITY,
2(2), 116-124.
Author URL.
Williams PH, Osborne JL (2009). Bumblebee vulnerability and conservation world-wide.
Apidologie,
40(3), 367-387.
Abstract:
Bumblebee vulnerability and conservation world-wide
We review evidence from around the world for bumblebee declines and review management to mitigate threats. We find that there is evidence that some bumblebee species are declining in Europe, North America, and Asia. People believe that land-use changes may be having a negative effect through reductions in food plants in many parts of the world, but that other factors such as pathogens may be having a stronger effect for a few species in some regions (especially for Bombus s. str. in North America). Evidence so far is that greater susceptibility to land-use change is associated world-wide with small climatic ranges, range edges, and late-starting colony-development cycles. More evidence is needed on the roles of pollen specialization, nest sites, hibernation sites, and pesticides. It is still too early to assess the success of schemes aimed at improving forage in agricultural and conservation areas. However, schemes aimed at raising public awareness have been very successful. Until proven safe, we recommend that live bumblebees should not be moved across continents or oceans for commercial pollination. © INRA/DIB-AGIB/EDP Sciences, 2009.
Abstract.
Niitepõald K, Smith AD, Osborne JL, Reynolds DR, Carreck NL, Martin AP, Marden JH, Ovaskainen O, Hanski I (2009). Flight metabolic rate and Pgi genotype influence butterfly dispersal rate in the field.
Ecology,
90(8), 2223-2232.
Abstract:
Flight metabolic rate and Pgi genotype influence butterfly dispersal rate in the field
Dispersal is a key life-history trait, especially in species inhabiting fragmented landscapes. The process of dispersal is affected by a suite of morphological, physiological, and behavioral traits, all of which have a more or less complex genetic basis and are affected by the prevailing environmental conditions. To be able to identify genetic and phenotypic effects on dispersal, movements have to be recorded over relevant spatial and temporal scales. We used harmonic radar to track free-flying Glanville fritillary butterflies {Melitaea cinxia) released in the field and reconstructed their flight tracks for several hours. Flight track lengths for individual butterflies ranged from tens of meters to several kilometers. Butterflies were most mobile at midday and in intermediate temperatures. Flight metabolic rate (MR), measured prior to the tracking, explained variation in mobility at all scales studied. One-third of the variation in the distance moved in one hour could be attributed to variation in flight MR. Heterozygous individuals at a single nucleotide polymorphism in the phosphoglucose isomerase (Pgi) gene moved longer distances in the morning and at lower ambient temperatures than homozygous individuals. A similar genotype × temperature interaction was found to affect the metabolic rate. Our results establish connections from molecular variation in a single gene to flight physiology and movement behavior at the landscape level. These results indicate a fitness advantage to the heterozygous genotype in low temperatures and suggest a mechanism by which varying environmental conditions maintain genetic polymorphism in populations. © 2009 by the Ecological Society of America.
Abstract.
Reynolds AM, Swain JL, Smith AD, Martin AP, Osborne JL (2009). Honeybees use a Levy flight search strategy and odour-mediated anemotaxis to relocate food sources.
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY,
64(1), 115-123.
Author URL.
Jacobs JH, Clark SJ, Denholm I, Goulson D, Stoate C, Osborne JL (2009). Pollination biology of fruit-bearing hedgerow plants and the role of flower-visiting insects in fruit-set.
Ann Bot,
104(7), 1397-1404.
Abstract:
Pollination biology of fruit-bearing hedgerow plants and the role of flower-visiting insects in fruit-set.
BACKGROUND AND AIMS: in the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). METHODS: the requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. KEY RESULTS: the proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. CONCLUSIONS: Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows.
Abstract.
Author URL.
2008
Osborne JL, Martin AP, Carreck NL, Swain JL, Knight ME, Goulson D, Hale RJ, Sanderson RA (2008). Bumblebee flight distances in relation to the forage landscape.
J Anim Ecol,
77(2), 406-415.
Abstract:
Bumblebee flight distances in relation to the forage landscape.
1. Foraging range is a key aspect of the ecology of 'central place foragers'. Estimating how far bees fly under different circumstances is essential for predicting colony success, and for estimating bee-mediated gene flow between plant populations. It is likely to be strongly influenced by forage distribution, something that is hard to quantify in all but the simplest landscapes; and theories of foraging distance tend to assume a homogeneous forage distribution. 2. We quantified the distribution of bumblebee Bombus terrestris L. foragers away from experimentally positioned colonies, in an agricultural landscape, using two methods. We mass-marked foragers as they left the colony, and analysed pollen from foragers returning to the colonies. The data were set within the context of the 'forage landscape': a map of the spatial distribution of forage as determined from remote-sensed data. To our knowledge, this is the first time that empirical data on foraging distances and forage availability, at this resolution and scale, have been collected and combined for bumblebees. 3. The bees foraged at least 1.5 km from their colonies, and the proportion of foragers flying to one field declined, approximately linearly, with radial distance. In this landscape there was great variation in forage availability within 500 m of colonies but little variation beyond 1 km, regardless of colony location. 4. The scale of B. terrestris foraging was large enough to buffer against effects of forage patch and flowering crop heterogeneity, but bee species with shorter foraging ranges may experience highly variable colony success according to location.
Abstract.
Author URL.
Cullen DW, Squire GR, McNicol JW, Jacobs JH, Osborne JL, Ford L, Ramsay G, Scrimgeour C, Young MW (2008). Development and validation of gas chromatography and real-time quantitative PCR for the quantification of landscape-scale gene flow from varieties of high erucic acid (HEAR) oilseed rape.
Journal of the Science of Food and Agriculture,
88(13), 2253-2264.
Abstract:
Development and validation of gas chromatography and real-time quantitative PCR for the quantification of landscape-scale gene flow from varieties of high erucic acid (HEAR) oilseed rape
BACKGROUND: High erucic acid oilseed rape (HEAR) was tested as a source crop for estimates of regional geneflow. Two methods to detect HEAR in low erucic acid oilseed rape (LEAR) were compared: real-time quantitative PCR (qPCR) and gas chromatography (GC). RESULTS: Fields (2.5 ha) of a LEAR variety (0.028% EA) in Tayside and Hertfordshire were juxtaposed adjacent to and 1 km distant from a HEAR (44% EA) field. The LEAR variety was a varietal association to ensure high cross-pollination (CP). The methods were highly correlated, measuring between 30% and 0.5% CP. However, the qPCR method became unreliable below 0.5% CP, whereas GC was robust enough to detect raised EA equivalent to one F1 seed in 500 (0.2%). A statistical mixture model was fitted to the distributions of EA in samples in order to assign a CP value to each 500-seed sample. Declines of CP from 30% to
Abstract.
Mauchline AL, Birkett MA, Woodcock CM, Pickett JA, Osborne JL, Powell W (2008). Electrophysiological and behavioural responses of the pollen beetle, Meligethes aeneus, to volatiles from a non-host plant, lavender, Lavandula angustifolia (Lamiaceae).
Arthropod-Plant Interactions,
2(2), 109-115.
Abstract:
Electrophysiological and behavioural responses of the pollen beetle, Meligethes aeneus, to volatiles from a non-host plant, lavender, Lavandula angustifolia (Lamiaceae)
A semiochemical based push-pull strategy for control of oilseed rape pests is being developed at Rothamsted Research. This strategy uses insect and plant derived semiochemicals to manipulate pests and their natural enemies. An important element within this strategy is an understanding of the importance of non-host plant cues for pest insects and how such signals could be used to manipulate their behaviour. Previous studies using a range of non-host plants have shown that, for the pollen beetle Meligethes aeneus (Coleoptera: Nitidulidae), the essential oil of lavender, Lavandula angustifolia (Lamiaceae), was the most repellent. The aim of this study was to identify the active components in L. angustifolia oil, and to investigate the behaviour of M. aeneus to these chemicals, to establish the most effective use of repellent stimuli to disrupt colonisation of oilseed rape crops. Coupled gas chromatography-electroantennography (GC-EAG) and gas chromatography-mass spectrometry (GC-MS) resulted in the identification of seven active compounds which were tested for behavioural activity using a 4-way olfactometer. Repellent responses were observed with (±)-linalool and (±)-linalyl acetate. The use of these chemicals within a push-pull pest control strategy is discussed. © Springer Science+Business Media B.V. 2008.
Abstract.
Damgaard C, Simonsen V, Osborne JL (2008). Prediction of pollen-mediated gene flow between fields of red clover (Trifolium pratense).
Environmental Modeling and Assessment,
13(4), 483-490.
Abstract:
Prediction of pollen-mediated gene flow between fields of red clover (Trifolium pratense)
Pollen-mediated gene flow between red clover fields by bumblebees is predicted by estimating or simulating the parameters in a gene flow model for insect-pollinated crops. Generally, the predicted level of gene flow was found to depend on the visiting bee species and the spatial arrangement of the red clover fields. When the fields are close to each other, the gene flow depends mainly on the typical foraging distance of the visiting bee species, but when the fields are far apart, the gene flow between red clover fields is more sensitive to the distances between red clover fields than to the actual bumblebee species that pollinates the fields. Using the suggested methodology, the gene flow may be predicted in different agricultural scenarios. For example, if the gene flow between red clover fields is mediated by Bombus terrestris and the red clover fields that were assumed to be quadrates with sides of 100 m are separated by 200 m, then the median gene flow is predicted to be 0.17%. © 2007 Springer Science+Business Media B.V.
Abstract.
Osborne JL, Martin AP, Shortall CR, Todd AD, Goulson D, Knight ME, Hale RJ, Sanderson RA (2008). Quantifying and comparing bumblebee nest densities in gardens and countryside habitats.
Journal of Applied Ecology,
45(3), 784-792.
Abstract:
Quantifying and comparing bumblebee nest densities in gardens and countryside habitats
1. Bumblebees provide an important pollination service to both crops and wild plants. Many species have declined in the UK, particularly in arable regions. While bumblebee forage requirements have been widely studied, there has been less consideration of whether availability of nesting sites is limiting. It is important to know which habitats contain the most bumblebee nests per unit area in order to guide conservation and management options; particularly in the light of current emphasis on environmental stewardship schemes for farmed landscapes. However, it is extremely difficult to map the distribution of bumblebee nests. 2. We describe the findings of the National Bumblebee Nest Survey, a structured survey carried out by 719 volunteers in the UK during early summer 2004. The surveyors used a defined protocol to record the presence or absence of bumblebee nests in prescribed areas of gardens, short grassland, long grassland and woodland, and along woodland edge, hedgerows and fence lines. The records allowed us to estimate the density of bumblebee nests in each of these habitats for the first time. 3. Nest densities were high in gardens (36 nests ha-1), and linear countryside habitats (fence lines, hedgerows, woodland edge: 20-37 nests ha-1), and lower in non-linear countryside habitats (woodland and grassland: 11-15 nests ha-1). 4. Findings on nest location characteristics corroborate those of an earlier survey carried out in the UK (Fussell & Corbet 1992). 5. Synthesis and applications. Gardens provide an important nesting habitat for bumblebees in the UK. In the countryside, the area occupied by linear features is small compared with that of non-linear features. However, as linear features contain high densities of nests, management options affecting such features may have a disproportionately large effect on bumblebee nesting opportunities. Current farm stewardship schemes in the UK are therefore likely to facilitate bumblebee nesting, because they provide clear guidance and support for 'sympathetic' hedgerow and field margin management. © 2007 the Authors.
Abstract.
Ovaskainen O, Smith AD, Osborne JL, Reynolds DR, Carreck NL, Martin AP, Niitepõld K, Hanski I (2008). Tracking butterfly movements with harmonic radar reveals an effect of population age on movement distance.
Proceedings of the National Academy of Sciences of the United States of America,
105(49), 19090-19095.
Abstract:
Tracking butterfly movements with harmonic radar reveals an effect of population age on movement distance
We used harmonic radar to track freely flying Glanville fritillary butterfly (Melitaea cinxia) females within an area of 30 ha. Butterflies originated from large and continuous populations in China and Estonia, and from newly established or old (> 5 years) small local populations in a highly fragmented landscape in Finland. Caterpillars were raised under common garden conditions and unmated females were tested soon after eclosion. The reconstructed flight paths for 66 individuals comprised a total distance of 51 km with high spatial resolution. Butterflies originating from large continuous populations and from old local populations in Finland exhibited similar movement behaviors, whereas butterflies originating from newly established local populations in the fragmented landscape in Finland moved significantly more than the others. There was no difference in the lengths of individual flight bouts, but the new-population females flew more frequently, resulting in longer daily movement tracks. The flight activity of all individuals was affected by environmental conditions, peaking at 19-23°C (depending on population type), in the early afternoon, and during calm weather. Butterflies from all population types showed a strong tendency to follow habitat edges between the open study area and the neighboring woodlands. © 2008 by the National Academy of Sciences of the USA.
Abstract.
2007
Reynolds AM, Smith AD, Reynolds DR, Carreck NL, Osborne JL (2007). Honeybees perform optimal scale-free searching flights when attempting to locate a food source.
Journal of Experimental Biology,
210(21), 3763-3770.
Abstract:
Honeybees perform optimal scale-free searching flights when attempting to locate a food source
The foraging strategies used by animals are key to their success in spatially and temporally heterogeneous environments. We hypothesise that when a food source at a known location ceases to be available, flying insects will exhibit search patterns that optimise the rediscovery of such resources. In order to study these searching patterns, foraging honeybees were trained to an artificial feeder that was then removed, and the subsequent flight patterns of the bees were recorded using harmonic radar. We show that the flight patterns have a scale-free (Lévy-flight) characteristic that constitutes an optimal searching strategy for the location of the feeder. It is shown that this searching strategy would remain optimal even if the implementation of the Lévy-flights was imprecise due, for example, to errors in the bees' path integration system or difficulties in responding to variable wind conditions. The implications of these findings for animal foraging in general are discussed.
Abstract.
Reynolds AM, Smith AD, Reynolds DR, Carreck NL, Osborne JL (2007). Honeybees perform optimal scale-free searching flights when attempting to locate a food source.
J Exp Biol,
210(Pt 21), 3763-3770.
Abstract:
Honeybees perform optimal scale-free searching flights when attempting to locate a food source.
The foraging strategies used by animals are key to their success in spatially and temporally heterogeneous environments. We hypothesise that when a food source at a known location ceases to be available, flying insects will exhibit search patterns that optimise the rediscovery of such resources. In order to study these searching patterns, foraging honeybees were trained to an artificial feeder that was then removed, and the subsequent flight patterns of the bees were recorded using harmonic radar. We show that the flight patterns have a scale-free (Lévy-flight) characteristic that constitutes an optimal searching strategy for the location of the feeder. It is shown that this searching strategy would remain optimal even if the implementation of the Lévy-flights was imprecise due, for example, to errors in the bees' path integration system or difficulties in responding to variable wind conditions. The implications of these findings for animal foraging in general are discussed.
Abstract.
Author URL.
Heard MS, Carvell C, Carreck NL, Rothery P, Osborne JL, Bourke AFG (2007). Landscape context not patch size determines bumble-bee density on flower mixtures sown for agri-environment schemes.
Biology Letters,
3(6), 638-641.
Abstract:
Landscape context not patch size determines bumble-bee density on flower mixtures sown for agri-environment schemes
Bumble-bee declines across Europe have been linked to loss of habitat and forage availability due to agricultural intensification. These declines may have severe ecological and commercial consequences since bumble-bees pollinate a range of wildflowers and crops. In England, attempts are being made to reintroduce forage resources through agri-environment schemes, yet there are few data on how the area of forage, or the landscape context in which it is provided, affects their success. We investigated the effects of sown forage patches on bumble-bees across sites varying in landscape characteristics. Bumble-bee densities were higher on sown patches compared with control habitats but did not vary with patch size, i.e. total forager numbers were proportional to patch area. Importantly, the relative response to sown forage patches varied widely across a landscape gradient such that their impact in terms of attracting foraging bumble-bees was greatest where the proportion of arable land was highest. © 2007 the Royal Society.
Abstract.
2006
Martin AP, Carreck NL, Swain JL, Goulson D, Knight ME, Hale RJ, Sanderson RA, Osborne JL (2006). A modular system for trapping and mass-marking bumblebees: Applications for studying food choice and foraging range.
Apidologie,
37(3), 341-350.
Abstract:
A modular system for trapping and mass-marking bumblebees: Applications for studying food choice and foraging range
Two new techniques for the study of bumblebee behavioural ecology are described. Interchangeable nest entrance modules allow (i) unimpeded bee traffic, (ii) trapping of incoming foragers for counting and removal of pollen loads; or (iii) colour marking of bees leaving the colony using dye powder. The forager traps captured all returning foragers while in place and 35% of them were carrying pollen loads. During the four week experiment, the percentage of mixed pollen loads decreased and the proportion of pollen loads from mass-flowering resources increased. The dye dispensers automatically marked 86% of foragers as they left the colony (approximately 28 bees per hour), and 37% of returning bees were marked. Different colours were used for bees in each colony, which could then be observed in the field. © INRA/DIB-AGIB/ EDP Sciences, 2006.
Abstract.
2005
Knight ME, Martin AP, Bishop S, Osborne JL, Hale RJ, Sanderson RA, Goulson D (2005). An interspecific comparison of foraging range and nest density of four bumblebee (Bombus) species.
Molecular Ecology,
14(6), 1811-1820.
Abstract:
An interspecific comparison of foraging range and nest density of four bumblebee (Bombus) species
Bumblebees are major pollinators of crops and wildflowers in northern temperate regions. Knowledge of their ecology is vital for the design of effective management and conservation strategies but key aspects remain poorly understood. Here we employed microsatellite markers to estimate and compare foraging range and nest density among four UK species: Bombus terrestris, Bombus pascuorum, Bombus lapidarius, and Bombus pratorum. Workers were sampled along a 1.5-km linear transect across arable farmland. Eight or nine polymorphic microsatellite markers were then used to identify putative sisters. In accordance with previous studies, minimum estimated maximum foraging range was greatest for B. terrestris (758 m) and least for B. pascuorum (449 m). The estimate for B. lapidanus was similar to B. pascuorum (450 m), while that of B. pratorum was intermediate (674 m). Since the area of forage available to bees increases as the square of foraging range, these differences correspond to a threefold variation in the area used by bumblebee nests of different species. Possible explanations for these differences are discussed. Estimates for nest density at the times of sampling were 29, 68, 117, and 26/km2 for B. terrestris, B. pascuorum, B. lapidarius and B. pratorum, respectively. These data suggest that even among the most common British bumblebee species, significant differences in fundamental aspects of their ecology exist, a finding that should be reflected in management and conservation strategies. © 2005 Blackwell Publishing Ltd.
Abstract.
Bohan DA, Boffey CWH, Brooks DR, Clark SJ, Dewar AM, Firbank LG, Haughton AJ, Hawes C, Heard MS, May MJ, et al (2005). Effects on weed and invertebrate abundance and diversity of herbicide management in genetically modified herbicide-tolerant winter-sown oilseed rape.
Proc Biol Sci,
272(1562), 463-474.
Abstract:
Effects on weed and invertebrate abundance and diversity of herbicide management in genetically modified herbicide-tolerant winter-sown oilseed rape.
We evaluated the effects of the herbicide management associated with genetically modified herbicide-tolerant (GMHT) winter oilseed rape (WOSR) on weed and invertebrate abundance and diversity by testing the null hypotheses that there is no difference between the effects of herbicide management of GMHT WOSR and that of comparable conventional varieties. For total weeds, there were few treatment differences between GMHT and conventional cropping, but large and opposite treatment effects were observed for dicots and monocots. In the GMHT treatment, there were fewer dicots and monocots than in conventional crops. At harvest, dicot biomass and seed rain in the GMHT treatment were one-third of that in the conventional, while monocot biomass was threefold greater and monocot seed rain almost fivefold greater in the GMHT treatment than in the conventional. These differential effects persisted into the following two years of the rotation. Bees and Butterflies that forage and select for dicot weeds were less abundant in GMHT WORS management in July. Year totals for Collembola were greater under GMHT management. There were few other treatment effects on invertebrates, despite the marked effects of herbicide management on the weeds.
Abstract.
Author URL.
Mauchline AL, Osborne JL, Martin AP, Poppy GM, Powell W (2005). The effects of non-host plant essential oil volatiles on the behaviour of the pollen beetle Meligethes aeneus.
ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA,
114(3), 181-188.
Author URL.
Cant ET, Smith AD, Reynolds DR, Osborne JL (2005). Tracking butterfly flight paths across the landscape with harmonic radar.
Proc Biol Sci,
272(1565), 785-790.
Abstract:
Tracking butterfly flight paths across the landscape with harmonic radar.
For the first time, the flight paths of five butterfly species were successfully tracked using harmonic radar within an agricultural landscape. Until now, butterfly mobility has been predominantly studied using visual observations and mark-recapture experiments. Attachment of a light-weight radar transponder to the butterfly's thorax did not significantly affect behaviour or mobility. Tracks were analysed for straightness, duration, displacement, ground speed, foraging and the influence of linear landscape features on flight direction. Two main styles of track were identified: (A) fast linear flight and (B) slower nonlinear flights involving a period of foraging and/or looped sections of flight. These loops potentially perform an orientation function, and were often associated with areas of forage. In the absence of forage, linear features did not provide a guiding effect on flight direction, and only dense treelines were perceived as barriers. The results provide tentative support for non-random dispersal and a perceptual range of 100-200 m for these species. This study has demonstrated a methodology of significant value for future investigation of butterfly mobility and dispersal.
Abstract.
Author URL.
2004
Mauchline AL, Osborne JL, Powell W (2004). Feeding responses of carabid beetles to dimethoate-contaminated prey.
AGRICULTURAL AND FOREST ENTOMOLOGY,
6(2), 99-104.
Author URL.
Cresswell JE, Osborne JL (2004). The effect of patch size and separation on bumblebee foraging in oilseed rape: implications for gene flow. Journal of Applied Ecology, 41(3), 539-546.
2003
Firbank LG, Heard MS, Woiwod IP, Hawes C, Haughton AJ, Champion GT, Scott RJ, Hill MO, Dewar AM, Squire GR, et al (2003). An introduction to the Farm-Scale Evaluations of genetically modified herbicide-tolerant crops.
JOURNAL OF APPLIED ECOLOGY,
40(1), 2-16.
Author URL.
Osborne JL, Free JB (2003). FLOWERING AND REPRODUCTION | Pollination. In (Ed) Encyclopedia of Applied Plant Sciences, 315-325.
Haughton AJ, Champion GT, Hawes C, Heard MS, Brooks DR, Bohan DA, Clark SJ, Dewar AM, Firbank LG, Osborne JL, et al (2003). Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods.
Philos Trans R Soc Lond B Biol Sci,
358(1439), 1863-1877.
Abstract:
Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods.
The effects of the management of genetically modified herbicide-tolerant (GMHT) crops on the abundances of aerial and epigeal arthropods were assessed in 66 beet, 68 maize and 67 spring oilseed rape sites as part of the Farm Scale Evaluations of GMHT crops. Most higher taxa were insensitive to differences between GMHT and conventional weed management, but significant effects were found on the abundance of at least one group within each taxon studied. Numbers of butterflies in beet and spring oilseed rape and of Heteroptera and bees in beet were smaller under the relevant GMHT crop management, whereas the abundance of Collembola was consistently greater in all GMHT crops. Generally, these effects were specific to each crop type, reflected the phenology and ecology of the arthropod taxa, were indirect and related to herbicide management. These results apply generally to agriculture across Britain, and could be used in mathematical models to predict the possible long-term effects of the widespread adoption of GMHT technology. The results for bees and butterflies relate to foraging preferences and might or might not translate into effects on population densities, depending on whether adoption leads to forage reductions over large areas. These species, and the detritivore Collembola, may be useful indicator species for future studies of GMHT management.
Abstract.
Author URL.
Roy DB, Bohan DA, Haughton AJ, Hill MO, Osborne JL, Clark SJ, Perry JN, Rothery P, Scott RJ, Brooks DR, et al (2003). Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES,
358(1439), 1879-1898.
Author URL.
Squire GR, Brooks DR, Bohan DA, Champion GT, Daniels RE, Haughton AJ, Hawes C, Heard MS, Hill MO, May MJ, et al (2003). On the rationale and interpretation of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES,
358(1439), 1779-1799.
Author URL.
Hawes C, Haughton AJ, Osborne JL, Roy DB, Clark SJ, Perry JN, Rothery P, Bohan DA, Brooks DR, Champion GT, et al (2003). Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herb icide-tolerant crops.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES,
358(1439), 1899-1913.
Author URL.
2002
Cresswell JE, Bell SA, Osborne JL (2002). A model of pollinator-mediated gene flow between plant populations with numerical solutions for bumblebees pollinating oilseed rape. Oikos, 98(3), 375-384.
Osborne J, Loxdale HD, Woiwood IP (2002). Monitoring insect dispersal: methods and approaches. In (Ed)
, 24-49.
Author URL.
2001
Osborne JL, Williams IH, Marshall AH, Michaelson-Yeates TPT (2001). Pollination and gene flow in white clover, growing in a patchy habitat.
Acta Horticulturae,
561, 35-40.
Abstract:
Pollination and gene flow in white clover, growing in a patchy habitat
In insect-pollinated plants, the effects of habitat fragmentation on gene flow are mediated through the foraging behaviour of pollinators, which will be modified by the relative attractiveness and density of resource patches and the relative constancy of pollinators to a target species and/or patch. Bee-mediated gene flow between groups of self-incompatible plants was quantified using five selection lines of white clover (Trifolium repens L.) with isoenzyme markers. The objectives were to investigate whether pollen flow and consequent gene flow reflected bee patch constancy and how pollen flow varied with distance and vegetation between donor and recipient plants. Groups of five clover plants were positioned on grass/herb patches, sown within a field of barley. Each group of plants contained one clover line. Seed paternity in three cohorts of inflorescences was determined using starch gel electrophoresis. Most (92%) of the sampled seed was sired by plants from the same group as the recipient plant. There was a significant negative relationship between pollen flow and distance between plant groups, and pollen flow declined significantly over time. There was some evidence that a strip of barley between the grass/herb patches acted as a barrier to pollen flow. In conclusion, pollen and gene flow reflected the bee patch constancy observed in a previous experiment, and short distances of separation (26 m) between plant groups led to restricted bee-mediated pollen flow.
Abstract.
Osborne JL, Williams IH (2001). Site constancy of bumble bees in an experimentally patchy habitat.
Agriculture, Ecosystems and Environment,
83(1-2), 129-141.
Abstract:
Site constancy of bumble bees in an experimentally patchy habitat
Habitat fragmentation alters the spatial and temporal distribution of floral resources in farmland. This will affect the foraging behaviour of bees utilising these resources and consequently pollen flow within and between patches of flowering plants. One element of bees' foraging behaviour, which is likely to be affected, is the degree to which individual bees remain constant to a particular site or patch, both within and between foraging trips. Mark-re-observation was used to investigate whether foraging bumble bees showed site constancy over several days to regular patches of forage, even when those patches contained qualitatively and quantitatively similar resources. The authors also investigated whether site constancy was affected by the arrangement of patches within the area. The experimental arena was a field of barley containing patches of a grass/herb mixture, including Centaurea nigra L. (black knapweed) which provided nectar and pollen for bumble bees, particularly Bombus lapidarius L. Patches were either contiguous or non-contiguous in patch groups. Twenty to 28% of marked B. lapidarius were re-observed in the experimental arena during the week following marking. The number of re-observations of bees decreased over time probably because floral density decreased, the bees sought alternative forage elsewhere or they died from natural causes. The bees showed striking site constancy: 86-88% of re-observations were constant to patch group (27 × 27 m2 or 45 × 45 m2) and fewer re-observations were constant to small patches (9 × 9 m2) within a patch group. Most observed moves were to patches or patch groups adjacent to those on which the bumble bees were marked. There was limited evidence that bumble bees were more constant to 9 × 9 m2 patches surrounded by barley (70-73% of re-observations were patch constant) than to 9 × 9 m2 patches that were contiguous (20-50% of re-observations were patch constant). The implications of the observed bumble bee site constancy for plant gene flow in the arable ecosystem are discussed. © 2001 Elsevier Science B.V.
Abstract.
2000
Cresswell JE, Osborne JL, Goulson D (2000). An economic model of the limits to foraging range in central place foragers with numerical solutions for bumblebees.
Ecological Entomology,
25(3), 249-255.
Abstract:
An economic model of the limits to foraging range in central place foragers with numerical solutions for bumblebees
1. A model is described that evaluates the maximum economic foraging range in central place foragers by using optimality criteria to discriminate between foraging sites at different distances from the forager's central place. 2. The basic model can be varied to suit foragers that optimise either their rate of net energy uptake or their foraging efficiency. 3. The model requires specification of the time and energy budgets of travel and foraging, and of the rewards obtainable at potential foraging sites. 4. The specific case of bumblebees, whose foraging ranges are poorly known, is considered. 5. Numerical solutions of the model for parameter values that represent bumblebees and their forage predict economic foraging ranges exceeding several kilometres. The model demonstrates that economics alone can explain extensive flight ranges in bees.
Abstract.
Capaldi EA, Smith AD, Osborne JL, Fahrbach SE, Farris SM, Reynolds DR, Edwards AS, Martin A, Robinson GE, Poppy GM, et al (2000). Ontogeny of orientation flight in the honeybee revealed by harmonic radar.
Nature,
403(6769), 537-540.
Abstract:
Ontogeny of orientation flight in the honeybee revealed by harmonic radar
Cognitive ethology focuses on the study of animals under natural conditions to reveal ecologically adapted modes of learning. But biologists can more easily study what an animal learns than how it learns. For example, honeybees take repeated 'orientation' flights before becoming foragers at about three weeks of age. These flights are a prerequisite for successful homing. Little is known about these flights because orienting bees rapidly fly out of the range of human observation. Using harmonic radar, we show for the first time a striking ontogeny to honeybee orientation flights. With increased experience, bees hold trip duration constant but fly faster, so later trips cover a larger area than earlier trips. In addition, each flight is typically restricted to a narrow sector around the hive. Orientation flights provide honeybees with repeated opportunities to view the hive and landscape features from different viewpoints, suggesting that bees learn the local landscape in a progressive fashion. We also show that these changes in orientation flight are related to the number of previous flights taken instead of chronological age, suggesting a learning process adapted to changes in weather conditions, flower availability and the needs of bee colonies.
Abstract.
1999
Osborne JL, Clark SJ, Morris RJ, Williams IH, Riley JR, Smith AD, Reynolds DR, Edwards AS (1999). A landscape-scale study of bumble bee foraging range and constancy, using harmonic radar.
Journal of Applied Ecology,
36(4), 519-533.
Abstract:
A landscape-scale study of bumble bee foraging range and constancy, using harmonic radar
1. Bumble bees play a vital role in the pollination of many crops and wild flowers, and plans for their conservation require a knowledge of the dynamics and spatial scale of their foraging flights, which are, at present, poorly understood. 2. We investigated the foraging range and constancy of two colonies of bumble bees Bombus terrestris L. on a mixed arable farm using harmonic radar, which has a unique capability to record the trajectories of insects flying at low altitude in the field. 3. Foraging bees were fitted with lightweight radar transponders and tracked as they flew to and from the nest to forage. The resulting tracks gave information on length, direction and straightness of foraging routes. Superimposition onto a map of the foraging landscape allowed interpretation of the bees' destinations in relation to the spatial distribution of forage. 4. Outward tracks had a mean length of 275.3 ± 18.5m (n = 65) and a range of 70-631 m, and were often to forage destinations beyond the nearest available forage. Most bees were constant to compass bearing and destination over successive trips, although one bee was tracked apparently switching between forage patches. Both outward and return tracks had a mean straightness ratio of 0.93 ± 0.01 (n = 99). The bees' ground speeds ranged from 3·0 ms-1 to 15·7 ms-1 (n = 100) in a variety of wind conditions. 5. The results support the hypothesis that bumble bees do not necessarily forage close to their nest, and illustrate that studies on a landscape scale are required if we are to evaluate bee foraging ranges fully with respect to resource availability. Such evaluations are required to underpin assessments of gene flow in bee-pollinated crops and wild flowers. They are also required when making decisions about the management of bees as pollinators and the conservation of bee and plant biodiversity.
Abstract.
Osborne JL (1999). Borage. Bee World, 80(1), 33-36.
Riley JR, Reynolds DR, Smith AD, Edwards AS, Osborne JL, Williams IH, McCartney HA (1999). Compensation for wind drift by bumble-bees.
NATURE,
400(6740), 126-126.
Author URL.
Carreck NL, Osborne JL, Capaldi EA, Riley JR (1999). Tracking bees with radar. Bee World, 80(3), 124-131.
1997
Osborne JL, Williams IH, Carreck NL, Poppy GM, Riley JR, Smith AD, Reynolds DR, Edwards AS (1997). Harmonic radar: a new technique for investigating bumblebee and honeybee foraging flight.
Author URL.
Osborne JL, Awmack CS, Clark SJ, Williams IH, Mills VC (1997). Nectar and flower production in Vicia faba L (field bean) at ambient and elevated carbon dioxide.
Apidologie,
28(1), 43-55.
Abstract:
Nectar and flower production in Vicia faba L (field bean) at ambient and elevated carbon dioxide
Atmospheric CO2 has been predicted to double by the year 2100. Elevated CO2 causes an increase in photosynthetic taste and extra assimilate is allocated to plant growth, seed and fruit production. Increased investment in flowers may have implications for pollination in entomophilous plants. Floral nectar standing crop, flower production and longevity were examined in Vicia faba, field bean, at ambient and elevated CO2. Nectar standing crop did not differ significantly between treatments but plants grown at elevated CO2 produced approximately 25% more flowers per plant and these lived 17% longer than those grown at ambient CO2. A plant grown at elevated CO2 may thus produce more nectar in total and, together with its increased floral display, may be more attractive to pollinators, but pollen flow will not necessarily be improved.
Abstract.
1996
Osborne JL (1996). Focusing on bumble bees.
BEE WORLD,
77(1), 57-61.
Author URL.
Riley JR, Smith AD, Reynolds DR, Edwards AS, Osborne JL, Williams IH, Carreck NL, Poppy GM (1996). Tracking bees with harmonic radar.
NATURE,
379(6560), 29-30.
Author URL.
1992
OSBORNE JL, SAVILLE NM (1992). BUMBLE BEES - SETTING THE RECORD STRAIGHT.
BEE WORLD,
73(4), 215-216.
Author URL.
1991
WILLIAMS IH, CORBET SA, OSBORNE JL (1991). BEEKEEPING, WILD BEES AND POLLINATION IN THE EUROPEAN COMMUNITY.
BEE WORLD,
72(4), 170-180.
Author URL.
CORBET SA, WILLIAMS IH, OSBORNE JL (1991). BEES AND THE POLLINATION OF CROPS AND WILD FLOWERS IN THE EUROPEAN COMMUNITY.
BEE WORLD,
72(2), 47-59.
Author URL.
OSBORNE JL, WILLIAMS IH, CORBET SA (1991). BEES, POLLINATION AND HABITAT CHANGE IN THE EUROPEAN COMMUNITY.
BEE WORLD,
72(3), 99-116.
Author URL.