Most carrion decomposition succession research has been primarily centered on entomological research. Insects are one group of invertebrates that are mostly noted for aiding in the decomposition process. However, there are other organisms that participate in the utilization of this common food fall, such as microorganisms. Not much is known about the identification and community structure of the microbial communities or even if they follow a pattern of succession as the decomposition of the carrion progresses. Also it is not known if there is variation in these ecological processes across differing deceased organisms or dependent on abiotic factors (i.e. temperature, moisture). The objective of this study was to evaluate microbial succession and insect species richness over decomposition. It was hypothesized that microbial communities on decomposing carcasses compared to the soil underneath them and 1m away would be different during decomposition, and that necrophagous insect species richness would vary both over time and between two seasons. To test for the effect of season on these communities, Sus scrofa carcasses (N=6) were placed in a forested habitat near Xenia, OH during spring (March 15th- June 8th) and summer (July 23rd – August 31st) 2009. Skin biopsies and swabs of the anus and mouth of each carcass were composited to compare with microbial community succession in soil underneath and 1m away over decomposition; standardized insect samples were also collected. Biolog ECOplates™, a phenotypic microarray that measures a microbial community metabolic profile (MCMP) using 31 different carbon sources, were employed to characterize microbial community succession.
Results/Conclusions
Two-way ANOVA with Bonferroni post-tests revealed significant differences in MCMPs between soil and carcass both over decomposition and between seasons (p<0.0001 for both). During spring and summer, insect species richness ranged from 1-4 and 1-6, respectively. These results demonstrate that there is community variation between substrates and across time, which infers that the microbial communities undergo ecological succession. Variation was also been observed with the invertebrates that colonized the carrion. During the summer trial, 1 out of the 6 pigs underwent a completely different pattern of succession with regards to the insects that colonized the carcass. Also, 2 genera of beetles were present during spring and not the summer, while another 3 genera where present during the summer and not the spring, demonstrating seasonal variation. It is concluded that our hypotheses about microbial community succession, variation amongst replicates and variation across seasons were all supported by the data.
