Animal personality drives individual dietary specialisation across multiple dimensions in a mammalian herbivore

1. Animal personality influences how individuals perceive and react to
different stimuli, such as food quality and predation risk, thereby
shaping foraging behaviour. As a consequence, animal personality is
predicted to influence the diet and dietary specialisation of individuals
within a population, but animal personality and dietary specialisation
have yet to be linked. 2. Here, we tested whether individual diet and
dietary specialisation are a function of animal personality, using an
arboreal herbivore, the common brushtail possum, as a model species. We
hypothesised that pro-active individuals have more diverse foraging
opportunities than reactive individuals. We therefore predicted that
pro-active animals (more exploratory, bold and more active) would be less
specialised, with a broader and higher-quality diet than their reactive
counterparts. We quantified the personality traits and dietary niche using
proportional similarity index and specialisation categories of possums (n
= 30) in a population flanking native eucalypt woodland and residential
gardens in suburban Sydney, Australia. 3. We found that personality traits
were related to the breadth and quality of the realised diets of
individual possums. As predicted, proactive individuals had a broad,
high-quality diet with less individual dietary specialisation than
reactive individuals. Highly exploratory individuals had a more diverse
diet than less exploratory individuals, and bold individuals were more
likely than shy individuals to consume plants on the ground. 4. Our study
demonstrates an important link between animal personality and individual
dietary specialisation. The finding that the personality of individuals is
associated with different diet choices within the same landscape is
fundamentally significant. First, personality as a driver of niche
partitioning likely reduces within-species competition and hence could
contribute to adaptive capacity. Second, the strength of ecological
processes arising from interactions (e.g. predator-prey and
plant-herbivore interactions) could differ among individuals according to
their personality traits. 5. Our findings are also relevant for
effectively managing both threatened native, and invasive species.
Management strategies will be improved by incorporating knowledge of
individual traits and their ecological consequences, plus the ecological
context of food- and fear-scapes.