Publications by category
Journal articles
Gruber J, Kahn A, Backwell PRY (2019). Risks and rewards: balancing costs and benefits of predator avoidance in a fiddler crab. Animal Behaviour, 158, 9-13.
Gruber J, Brown G, Whiting MJ, Shine R (2018). Behavioural divergence during biological invasions: a study of cane toads (. <i>Rhinella marina</i>. ) from contrasting environments in Hawai'i.
Royal Society Open Science,
5(4), 180197-180197.
Abstract:
Behavioural divergence during biological invasions: a study of cane toads (. Rhinella marina. ) from contrasting environments in Hawai'i
. Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion
. per se
. (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads; range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural divergence might be a response to range expansion and invasion
. per se
. or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932; and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical divergence in behavioural traits in a climatically diverse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all behaviours that we scored, suggesting that founder effects, genetic drift, or developmentally plastic responses to ecological factors other than climate may have driven behavioural divergence between islands.
.
Abstract.
Gruber J, Whiting MJ, Brown G, Shine R (2018). Effects of rearing environment and population origin on responses to repeated behavioural trials in cane toads (Rhinella marina). Behavioural Processes, 153, 40-46.
Gruber J, Cunningham GD, While GM, Wapstra E (2017). Disentangling sex allocation in a viviparous reptile with temperature‐dependent sex determination: a multifactorial approach. Journal of Evolutionary Biology, 31(2), 267-276.
Gruber J, Brown G, Whiting MJ, Shine R (2017). Geographic divergence in dispersal-related behaviour in cane toads from range-front versus range-core populations in Australia. Behavioral Ecology and Sociobiology, 71(2).
Gruber J, Brown G, Whiting MJ, Shine R (2017). Is the behavioural divergence between range-core and range-edge populations of cane toads (. <i>Rhinella marina</i>. ) due to evolutionary change or developmental plasticity?.
Royal Society Open Science,
4(10), 170789-170789.
Abstract:
Is the behavioural divergence between range-core and range-edge populations of cane toads (. Rhinella marina. ) due to evolutionary change or developmental plasticity?
. Individuals at the leading edge of expanding biological invasions often show distinctive phenotypic traits, in ways that enhance their ability to disperse rapidly and to function effectively in novel environments. Cane toads (
. Rhinella marina
. ) at the invasion front in Australia exhibit shifts in morphology, physiology and behaviour (directionality of dispersal, boldness, risk-taking). We took a common-garden approach, raising toads from range-core and range-edge populations in captivity, to see if the behavioural divergences observed in wild-caught toads are also evident in common-garden offspring. Captive-raised toads from the invasion vanguard population were more exploratory and bolder (more prone to ‘risky’ behaviours) than toads from the range core, which suggests that these are evolved, genetic traits. Our study highlights the importance of behaviour as being potentially adaptive in invasive populations and adds these behavioural traits to the increasing list of phenotypic traits that have evolved rapidly during the toads' 80-year spread through tropical Australia.
.
Abstract.
Gruber J, Whiting MJ, Brown G, Shine R (2017). The loneliness of the long-distance toad: invasion history and social attraction in cane toads (. <i>Rhinella marina</i>. ).
Biology Letters,
13(11), 20170445-20170445.
Abstract:
The loneliness of the long-distance toad: invasion history and social attraction in cane toads (. Rhinella marina. )
. Individuals at the leading edge of a biological invasion constantly encounter novel environments. These pioneers may benefit from increased social attraction, because low population densities reduce competition and risks of pathogen transfer, and increase benefits of information transfer. In standardized trials, cane toads (
. Rhinella marina
. ) from invasion-front populations approached conspecifics more often, and spent more time close to them, than did conspecifics from high-density, long-colonized populations.
.
Abstract.
Publications by year
2019
Gruber J, Kahn A, Backwell PRY (2019). Risks and rewards: balancing costs and benefits of predator avoidance in a fiddler crab. Animal Behaviour, 158, 9-13.
2018
Gruber J, Brown G, Whiting MJ, Shine R (2018). Behavioural divergence during biological invasions: a study of cane toads (. <i>Rhinella marina</i>. ) from contrasting environments in Hawai'i.
Royal Society Open Science,
5(4), 180197-180197.
Abstract:
Behavioural divergence during biological invasions: a study of cane toads (. Rhinella marina. ) from contrasting environments in Hawai'i
. Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion
. per se
. (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads; range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural divergence might be a response to range expansion and invasion
. per se
. or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932; and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical divergence in behavioural traits in a climatically diverse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all behaviours that we scored, suggesting that founder effects, genetic drift, or developmentally plastic responses to ecological factors other than climate may have driven behavioural divergence between islands.
.
Abstract.
Gruber J, Whiting MJ, Brown G, Shine R (2018). Effects of rearing environment and population origin on responses to repeated behavioural trials in cane toads (Rhinella marina). Behavioural Processes, 153, 40-46.
2017
Gruber J, Cunningham GD, While GM, Wapstra E (2017). Disentangling sex allocation in a viviparous reptile with temperature‐dependent sex determination: a multifactorial approach. Journal of Evolutionary Biology, 31(2), 267-276.
Gruber J, Brown G, Whiting MJ, Shine R (2017). Geographic divergence in dispersal-related behaviour in cane toads from range-front versus range-core populations in Australia. Behavioral Ecology and Sociobiology, 71(2).
Gruber J, Brown G, Whiting MJ, Shine R (2017). Is the behavioural divergence between range-core and range-edge populations of cane toads (. <i>Rhinella marina</i>. ) due to evolutionary change or developmental plasticity?.
Royal Society Open Science,
4(10), 170789-170789.
Abstract:
Is the behavioural divergence between range-core and range-edge populations of cane toads (. Rhinella marina. ) due to evolutionary change or developmental plasticity?
. Individuals at the leading edge of expanding biological invasions often show distinctive phenotypic traits, in ways that enhance their ability to disperse rapidly and to function effectively in novel environments. Cane toads (
. Rhinella marina
. ) at the invasion front in Australia exhibit shifts in morphology, physiology and behaviour (directionality of dispersal, boldness, risk-taking). We took a common-garden approach, raising toads from range-core and range-edge populations in captivity, to see if the behavioural divergences observed in wild-caught toads are also evident in common-garden offspring. Captive-raised toads from the invasion vanguard population were more exploratory and bolder (more prone to ‘risky’ behaviours) than toads from the range core, which suggests that these are evolved, genetic traits. Our study highlights the importance of behaviour as being potentially adaptive in invasive populations and adds these behavioural traits to the increasing list of phenotypic traits that have evolved rapidly during the toads' 80-year spread through tropical Australia.
.
Abstract.
Gruber J, Whiting MJ, Brown G, Shine R (2017). The loneliness of the long-distance toad: invasion history and social attraction in cane toads (. <i>Rhinella marina</i>. ).
Biology Letters,
13(11), 20170445-20170445.
Abstract:
The loneliness of the long-distance toad: invasion history and social attraction in cane toads (. Rhinella marina. )
. Individuals at the leading edge of a biological invasion constantly encounter novel environments. These pioneers may benefit from increased social attraction, because low population densities reduce competition and risks of pathogen transfer, and increase benefits of information transfer. In standardized trials, cane toads (
. Rhinella marina
. ) from invasion-front populations approached conspecifics more often, and spent more time close to them, than did conspecifics from high-density, long-colonized populations.
.
Abstract.