Is Resource Change a Useful Predictor of Carrion Insect Succession on Pigs and Humans?

Carrion is a dynamic and nutrient-rich resource that attracts numerous insect species that undergo succession due to the rapid change in the carrion resource. Despite this process being well-understood, few studies have examined resource change as a driver of carrion insect succession, and instead have focused on the effects of time per se, or on coarse, qualitative measures such as decay stage. Here we report on three field succession experiments using pig carcasses and human cadavers encompassing two winters and one summer. We quantified the effects of resource change (measured as total body score, TBS), carrion type, initial carrion mass, ambient temperature, and season on insect species richness and community composition. We found that all variables had an effect on different taxonomic or trophic components of the insect community composition, with the exception of initial carrion mass which had no effect. We found significant positive effects of TBS on beetle species richness and composition, while fly species richness was not significantly affected by TBS, but was by ambient temperature. TBS had a significant positive effect on all trophic groups, while ambient temperature also had a significant positive effect on the necrophages and predator/parasitoids. Our study indicates that resource change, as indicated by TBS, is an important driver of carrion insect species turnover and succession on carrion, and that TBS can provide information about insect ecological patterns on carrion that other temporal measures of change cannot.