Necrophagous invertebrate community assembly in relation to microbial metabolic activity on a carrion resource: exploring ecological mechanisms of vertebrate decomposition

Understanding the mechanisms of carrion decomposition offers novel information for questions of theoretical ecology that address the role of chemical cues influencing community assembly rules, perhaps through interkingdom interactions. In this study, we evaluated necrophagous invertebrate community assembly on replicate Sus scrofa (swine) carcasses (N=3-6) in a forested habitat near Xenia, OH during spring (March 15 - June 8, 2009), summer (July 23 - August 31, 2009), autumn (November 11, 2009 - May 1, 2010) and winter (February 2- May 1, 2010) using standardized aerial sweeps for blow fly adults and larval hand collections throughout decomposition. To test the hypothesis that invertebrate colonization and subsequent community assembly were associated with changes in microbial metabolic activity, we took swab samples from each carcass to evaluate differential and collective microbial carbon-resource use (i.e., function) with Biolog EcoPlatesTM. Using non-metric multidimensional scaling (NMDS), multi-response permutation procedure (MRPP), indicator species analysis (ISA) and two-way ANOVA we found that there were significant differences in overall community structure of necrophagous invertebrate assemblages and microbial communities between seasons. During summer decomposition there were significant patterns of microbial functional succession (results of NMDS and MRPP) that were related to trends in invertebrate community assembly on the carrion; however, there were departures of these associations in autumn and winter. There were also significant indicator carbon-resources (results from ISA and two-way ANOVA) that corresponded with changes in invertebrate communities during decomposition, providing preliminary evidence that microbial use of carbon resources may influence carrion invertebrate succession through unknown interkingdom interactions.