Overview

Broad research specialisms

I study the evolution and ecology of social behavior, using insect societies as model systems. Most people are familiar with large-colony social insects such as ants and the domesticated honeybee, but it is the so-called primitively social species living in much smaller colonies, like paper wasps and sweat bees, that give us the best chance of understanding why sociality evolved in the first place. Why is this? While individual honeybees and ants have lost the ability to nest independently, worker paper wasps, sweat bees and other small-colony species hardly differ morphologically from their queens, and are still quite capable of independent reproduction. This means that by comparing females that nest independently with females living in groups, we can measure the advantages and disadvantages of sociality directly, and thus understand the conditions under which it could have evolved. And because groups are so small in primitively social species – often just a handful of workers with their queen – and colonies are relatively short-lived – it is also feasible to track every individual in every group and measure their lifetime reproductive success in a matter of weeks or months. Not only that, but wasps and bees can be socially polymorphic. In a socially polymorphic species, some populations are social, with nests containing queens and workers, while other populations of the same species are non-social, with each individual having its own nest and reproducing on its own. This polymorphism provides particularly good raw material for our over-arching aim, which is to understand fundamental features of social evolution at both behavioural and genomic levels.

Our work involves a combination of innovative, large-scale manipulative field experiments to test theoretical predictions; mathematical modelling; and molecular work using transcriptomics to look at gene expression and microsatellite markers to estimate genetic relatedness and assign offspring to parents. Our study organisms include (1) socially polymorphic sweat bees that nest in burrows in the ground (Halictus, Lasioglossum, UK and Europe); (2) primitively social wasps that construct open air nests using paper, mud or silk paper-wasps (Polistes, Spain), hover wasps (Liostenogaster, Malaysia) and silk wasps (Microstigmus, neotropics); as well as (3) non-social digger wasps (Ammophila, UK). We have used these diverse study systems to make some key discoveries about how and why insect sociality evolves. We have demonstrated that the typical life-history of wasps and bees, where mothers are unlikely to live long enough to bring their helpless offspring through to adulthood, was probably a major driver towards group living (see our paper in Nature). We also showed how this somewhat paradoxical life-history may have evolved in the first place in ancestral non-social species, perhaps pre-adapting them for sociality (see our paper in Nature). The main paradigm used to explain why individuals give up their own chance of reproduction to become workers is that they are working for a genetically related queen: by boosting the reproduction of a relative who carries copies of their own genes, workers effectively reproduce indirectly. In our paper wasp (Polistes) study system, however, many workers are completely unrelated to the queen, providing a challenge to traditional theory. Surprisingly, we found that worker paper wasps in fact produce enough offspring of their own - by laying occasional eggs themselves, or by eventually taking over the queen position - to make group-living, even with non-relatives, a more profitable option than nesting alone (see our paper in Science). The possibility of inheriting the queen position differs for each individual, and this leads to major differences in behaviour. Remarkably, in the Malaysian hover wasps we study, there is an age-based queue to become the queen. It is always the oldest female in the group who is queen, and if we remove her, the next-oldest female takes her place (a 'gerontocracy'). Older workers, nearer to the front of the queue, have more to lose and are correspondingly more risk-averse. Not wanting to jeopardize their bright futures as potential queens, these older workers are lazier, and spend less time foraging away from the safety of their nests (see our paper in Nature).

As well as understanding why social behaviour might have been favoured by natural selection, we are interested in how it evolved mechanistically. It remains unclear how a single mother queen can produce such very different classes of offspring: short-lived specialized foragers (workers), but also long-lived egg-laying machines (new queens). We are currently using transcriptomics to investigate how genetic constraints preventing the evolution of queen and worker castes can be overcome during evolution. One of the keys to this may be social plasticity, exemplified by socially polymorphic sweat bees. For example, northern populations of the sweat bee Halictus rubicundus are non-social, with each bee reproducing independently in its own nest. In contrast, nests in southern populations are usually social, with queens and workers. By transplanting queens from a northern to a southern field site, we can directly induce a transition from non-sociality to sociality within the same species (see our paper in Current Biology). The implication is that transitions may often represent condition-sensitive plasticity, or selection at just a few key developmental switch loci, rather than repeated evolutionary gains and losses of large suites of traits.

We are always keen to host young researchers who are interested in fundamental questions about social evolution. If you would like to explore the possibility of applying for a fellowship to join our group, and need help with your application, contact Prof Jeremy Field.

Qualifications

1987 PhD in Zoology (University of Cambridge)
1982 First Class BA (Hons.) in Zoology (University of Cambridge)

Career

2017-present: Professor of Evolutionary Biology, Centre for Ecology and Conservation, University of Exeter (Penryn Campus)

2007-2016: Professor, School of Life Sciences, University of Sussex
        
1995-2007: Lecturer/Senior Lecturer/Professor, Department of Biology, University College London

1994-1995: Huxley Research and Teaching Fellowship, Department of Ecology & Evolutionary Biology, Rice University, Houston, Texas

1991-1993: Postdoctoral Research Associate, Department of Zoology, University of Cambridge

1989- 1990: Postdoctoral Research Fellowship, Department of Biology, University of York

1987- 1989: Postdoctoral Research Fellowship, Department of Pure & Applied Biology, Imperial College at Silwood Park

Research group links

• Behavioural Ecology
• Insect Evolutionary Ecology

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Research

Research interests

My research group aims to understand fundamental features of social evolution at both behavioural and genomic levels, using social insects as model systems.

Research projects

Include the following (see below for some more details):

•    Social plasticity and the evolution of queen and worker castes
•    Within-group conflict
•    The evolution of parental care strategies
•    Environmental influences on social phenotype
•    An independent origin of sociality in silk wasps (Microstigmus): evolution and behaviour

Social plasticity and the evolution of castes

The morphologically specialized queen and worker castes of social insects represent the most extreme examples of irreversible reproductive altruism. Completely sterile workers that function as living nest entrances, or as food storage containers for their colonies, live alongside much larger queens that can sometimes lay >1 million eggs in a single month! The origin of sociality, involving this reproductive division of labour between the members of a society, thus represents one of the major transitions during evolution. The key testing grounds for theories about the evolutionary origin of castes are the so-called primitively eusocial species, such as paper wasps (Polistes) and sweat bees (Lasioglossum, Halictus), in which queens and workers do not differ morphologically. Social phenotype varies within these species, depending on factors such as latitude and altitude. Recently, by transplanting sweat bees between field sites, we directly induced transitions between sociality and non-sociality within a species. The implication is that transitions may often represent condition-sensitive plasticity, or selection at just a few key developmental switch loci, rather than repeated evolutionary gains and losses of large suites of traits.
Their social polymorphism, and the existence of closely related social and non-social species, means that sweat bees are also excellent models for understanding the origin of sociality at the genomic level. How can a single mother queen produce such very different classes of offspring: short-lived specialized foragers (workers), but also long-lived egg-laying machines (new queens)? We are currently using transcriptomics in combination with field experiments to investigate genetic constraints on the evolution of castes, and whether plasticity facilitates the resolution of these constraints during caste evolution.

Within-group conflict in paper wasps

My research group has been using paper wasps (Polistes) as a long-term model system to investigate why helping evolves, and to understand within-group conflicts that occur, for example, over how hard helpers should work to rear offspring of the dominant egg-layer or queen. Initial work in collaboration with Prof Mike Cant (Exeter, Biosciences) showed that helpers work less hard when they are nearer to the front of the queue to inherit the egg-laying position: high-rankers have more to lose by working. More recently, we have manipulated entire populations to show that market forces beyond the nest itself influence helping effort. Paper wasp helpers frequently switch nests, indicating that they have a choice of places to work. This suggested that there might be a 'market' for a helper's services, similar to a human market. We indeed found that if we increased the number of options available to helpers, they worked less hard: they got a better deal when the market was larger, as predicted by theoretical models (see our paper in Nature Communications). Currently, we are investigating the extent to which queens manipulate the phenotypes of their worker offspring in their own interests. Do queens handicap their own offspring so that they have little choice but to become workers, and will be unable to compete for egg-laying rights?

Invertebrate parental care strategies

Invertebrate parental care strategies are incredibly diverse, ranging from simple egg-guarding to the most complex animal societies. Why have these different strategies evolved? We investigate this using experimental field studies and phylogenetically-controlled comparative approaches with presocial wasps such as the genus Ammophila, as well as social taxa such as silk wasps (Microstigmus). We are particularly interested in progressive provisioning, where mothers feed their offspring gradually as they grow, just like many birds. Progressive provisioning is often regarded as a preadaptation for the evolution of sociality, and it has evolved several times in wasps and bees from the ancestral condition, where each offspring receives just a single large mass of food at the time the egg is laid, and is then left to develop by itself. Progressive provisioning has inherent disadvantages because it prolongs the period during which offspring depend on their mothers for food. We are interested in situations where there are advantages that can counteract this.

We also use Ammophila as a model to study kin recognition: how do helpers ensure that their help is directed towards genetic relatives, who carry copies of their genes? In Ammophila, intraspecific cuckoo parasitism is rife. A female parasitizes a second 'host' female of the same species by replacing the host egg with an egg her own, effectively stealing the host’s parental care. We are currently interested in why some hosts appear to recognize and reject foreign eggs, while others fail to do so, thus wasting their parental effort on raising an unrelated cuckoo.

Grants/Funding

2023-2027: NERC Pushing the Frontiers grant (PI)
Role specialization and plasticity at the origin of eusociality

2017-23: ERC Advanced Grant (PI)
Sharing a genome: caste antagonism and coadaptation in social insects

2015-2018: NERC standard research grant (PI)
Queen-worker coadaptation and conflict in a primitively eusocial bee

2013-2017: NERC standard research grant (PI)
The formation of eusocial groups: partner choice, conflict and the role of the market

2011-15: Senior Scientist for Marie Curie Individual Award to Dr James Gilbert
Do nutritionally poor environments promote sociality?

2012-14: Senior Scientist for Swiss National Science Foundation Individual Award to Dr Roger Schürch
Social behaviour of bees in the changing climate

2008-11: NERC standard research grant (PI)
Unrelated helpers in social wasps

2006-2009: NERC standard research grant (PI; Co-I Robert Paxton)
Environmental and genetic components of a major evolutionary transition: social plasticity in halictine bees

2002-2005: NERC standard research grant (PI)
Future fitness and helping in social queues

1998-2001: NERC standard research grant (PI)
Demographic advantages in the evolution of eusociality’

1996-99: NERC standard research grant (PI)
The origins of eusociality: offspring helping decisions in stenogastrine wasps

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Publications

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External Engagement and Impact

Committee/panel activities

Philip Leverhulme Prizes in Biology Panel

NERC Peer Review College

UKRI Future Leaders Fellowships Peer Review College

Editorial responsibilities

Behavioral Ecology & Sociobiology (Associate Editor)

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Teaching

Modules

2023/24

• BIO2430 - Behavioural Ecology

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Supervision / Group

Postdoctoral researchers

Postgraduate researchers

Research Technicians

Alumni

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Office Hours:

Term-time office hours:

Thursday 4-5pm

Friday 4-5pm

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