Data from: Ecological opportunity drives individual dietary specialisation in leopards

1. Individual specialisation, when individuals exploit only a subset of
resources utilised by the population, is a widespread phenomenon. It
provides the basis for evolutionary diversification and can impact
population and community dynamics. Both phenotypic traits and
environmental conditions are predicted to influence individual
specialisation; however, its adaptive consequences are poorly understood,
particularly among large mammalian carnivores that play an important role
in shaping ecosystems. 2. We used observations of 2960 kills made by 49
leopards Panthera pardus in the Sabi Sand Game Reserve, South Africa, to
quantify the magnitude of individual dietary specialisation in a solitary
large carnivore, and to examine the proximate and ultimate drivers of this
behaviour. 3. We found evidence of individual specialisation in leopard
diet, with respect to both the species and size of prey killed. Males
tended to be more specialised than females, likely because they could
access a wider range of prey due to larger body size. Similarly,
individuals that encountered a greater diversity of prey tended to be more
specialised. Our results confirmed that ecological opportunity was a key
determinant of individual specialisation; however, contrary to
predictions, per capita resource availability (and by extension,
intraspecific competition) did not affect the degree of specialisation
exhibited by individuals. 4. Surprisingly, dietary specialisation appeared
to disadvantage male leopards. Specialist males overlapped with fewer
resident females, had fewer cubs born on their home ranges, and had fewer
cubs survive to independence on their home ranges than generalist males.
This may have resulted from the high degree of environmental stochasticity
experienced during our study, as dietary specialisation is expected to
advantage individuals more during periods of resource predictability. 5.
In summary, we showed that a species usually considered to be a dietary
generalist was in fact a heterogenous collection of specialist and
generalist individuals. Individual specialisation is typically assumed to
be maintained by disruptive and/or fluctuating selection; hence, the
somewhat paradoxical coexistence of both in the same population might be
explained by a dynamic evolutionary equilibrium that exists between
specialists and generalists, in which each benefit under different
conditions. 08-Aug-2019