No abstract

Predators attack and plants defend, so herbivores face the dilemma of how to eat enough without being eaten. But do differences in the personality of herbivores affect the foraging choices of individuals? We explored the ecological impact of personality in a generalist herbivore, the brushtail possum (Trichosurus vulpecula). After quantifying personality traits in wild individuals brought temporarily into captivity, we tested how these traits altered foraging by individuals when free-ranging in their natural habitat. To measure their responses to the dual costs of predation risk and plant toxin, we varied the toxin concentration of food in safe foraging patches against paired, non-toxic risky patches, and used a novel synthesis of a manipulative Giving-Up-Density (GUD) experiment and video behavioural analysis. At the population level, the cost of safe patches pivoted around that of risky patches depending on food toxin concentration. At the individual level, boldness affected foraging at risky high-quality food patches (as behavioural differences between bold and shy), and at safe patches only when food toxin concentration was low (as differences in foraging outcome). Our results ecologically validate the personality trait of boldness, in brushtail possums. They also reveal, for the first time, a nuanced link between personality and the way in which individuals balance the costs of food and fear. Importantly, they suggest that high plant defence effectively attenuates differences in foraging behaviour arising from variation in personality, but poorly defended plants in safe areas should be differentially subject to herbivory depending on the personality of the herbivore.

No abstract

Herbivores live in a landscape of fear and must incorporate danger in their foraging decisions, balancing their need of food and safety using a variety of cues to assess the risk of predation. These cues can either be direct (i.e. signalling the possible presence of a predator) or indirect (i.e. linked to the likelihood of encountering a predator). How then do herbivores negotiate these multiple cues in the landscape? And which type of cues do foraging herbivores use to assess variation in predation risk? We examined these questions by investigating the foraging responses of a free-ranging marsupial herbivore, the common brushtail possum Trichosurus vulpecula to perceived predation risk. We found that indirect habitatrelated cues of predation (i.e. feeder location) consistently influenced foraging, while other more variable indirect (i.e. illumination) and direct cues (i.e. predator odour) did not. Giving-up-density at above-ground feeders was always lower than at on-ground feeders. Possums spent more time and foraged more at the aboveground feeders than at the on-ground feeders. Our results demonstrate that when multiple cues are present, varying in the accuracy of the information they provide about predation risk, possums respond to habitat-related cues. Possums manage risk by modifying behaviours, reducing time spent foraging in areas where potential risk is perceived as high. Thus, when the location of a predator at a certain point in time and space is unknown, and food demands are high, habitat-related cues are a safe choice to assess predation risk, with reliable returns for free-ranging herbivores.

responses of free-ranging western grey kangaroos (Macropus fuliginosus) to olfactory cues of historical and recently introduced predators. Austral Ecology 39 (1): pp. 115-121, which has been published in final form at