Differential Carbon Utilization by Bacteria in the Soil Surrounding and on Swine Carcasses with Dipteran Access Delayed

Mass mortality events can saturate an environment with decomposing remains. We lack an understanding of such perturbations and the extent of disruption imposed on the local ecosystem. During such instances, normal patterns of colonization and decomposition of remains by necrophagous arthropods can be retarded resulting in delayed colonization due to the proximity of multiple corpses. Therefore, this study was initiated to investigate the impact of carcasses in close proximity with delayed arthropod access on the associated microbial metabolic community profiles and those in the soil immediately under and adjacent to the remains. Field trials were conducted during the summers of 2013 and 2014 in Texas, USA. Three groups of pig carcasses were accessed: those immediately colonized by dipteran species (i.e., primary invertebrate consumers of carrion) and those experiencing delayed dipteran access by 7 or 14 days. Meteorological data for 2013 showed that the mean temperature was 30.59 ± 7.81 °C, accumulated degree hours (ADH) was 30,131.50, and precipitation was 39.12 mm, while in 2014, the mean temperature was 29.27 ± 6.49 °C, ADH was 28,090.70, and total precipitation was 171.45 mm. Bacterial function on the remains in terms of carbon utilization was significantly different between the years as well as between carcass groups, suggesting an inter-kingdom correlation between bacteria and dipteran activity. In contrast, microbial function in the soil was inconsistent between trials, indicating stochasticity within the system, probably due to differences in abiotic factors such as temperature, ADH, and rainfall.