Life-History Responses to Pathogens in Tiger Salamander (Ambystoma tigrinum) Larvae

We tested whether the presence of an iridovirus (Ambystoma tigrinum virus; ATV) could alter patterns of larval life histories in Arizona Tiger Salamanders (Ambystoma tigrinum nebulosum). Viral epidemics cause extreme mortality in natural populations and, thus, impose a strong selective force. We tested how exposure to ATV during larval development influences survival, growth, and frequency of cannibalism by manipulating the presence of ATV in replicated experimental tanks. ATV significantly reduced survival and larval growth. Propensity to become cannibalistic was not related to ATV exposure, suggesting that salamanders cannot facultatively respond to the presence of diseased conspecifics by reducing cannibalism. Our results demonstrate that viral pathogens may have both a direct and indirect effect on A. tigrinum fit- ness by reducing survival and growth rate.