Environmental variation and behaviour: resource availability during ontogeny and feeding performance in salamander larvae (Ambystoma texanum)


ERIC F. MAURER Centre for Ecology, Evolution and Behaviour, 101 Morgan Building, University of Kentucky, Lexington, KY 40506–0225, U.S.A.


1. The effects of resource availability during ontogeny on subsequent feeding performance were investigated in larvae of the small-mouthed salamander (Ambystoma texanum).

2. Salamander larvae were reared individually in either high or low prey density treatments for 7 weeks prior to intermediate prey density foraging trials. Larvae from the low prey density treatment were on average 35% smaller in body size than individuals from the high prey density treatment.

3. Resource availability during development influenced larval feeding rates and altered the relationship between body size and three feeding performance measures (attack rates, capture success and feeding rates). Feeding rates in predation trials were also positively correlated with growth rate early in the larval period (until the end of week 5).

4. These results suggest that the environment to which developing organisms are exposed can have significant effects on subsequent behaviour, and that small-mouthed salamander larvae may show state-dependent changes in feeding behaviour in response to differences in long-term feeding history. Additionally, differences in feeding performance may influence the probability of survival to the adult stage for organisms that utilize ephemeral habitats.