Investigating the impact of a human decomposition facility on local blow fly (Diptera: Calliphoridae) diversity

The utilization of human decomposition facilities for forensic entomology research is invaluable, though still rare in the United States. A primary criticism focuses on the constant influx of decomposition products into the environment, claiming that an over-saturated environment significantly alters carrion arthropod fauna. This hypothesis was tested two decades ago at the Anthropology Research Facility (ARF; University of Tennessee) and was not supported. We aimed to investigate whether these results are still valid and determine if seasonality also impacts species diversity and evenness. Adult blow flies (Diptera: Calliphoridae) were collected at one decomposition site (ARF) and two non-decomposition sites (UT Gardens and Ijam’s Nature Center). Each collection lasted 20 minutes, with four collections per site made in the early summer, and two collections per site made in late summer, early fall, and late fall. Flies were identified to species, diversity measures were calculated in R, and an ANOVA was performed to determine statistical significance. The ARF was significantly less diverse (P = 0.04) and less even (P = 0.01) than the other sites in the early summer, and less even than the other sites in early fall (P = 0.02). No other differences were found. Our results indicate that over-saturation at decomposition facilities may be important during times of seasonal shifts (e.g., early summer), potentially because the constant supply of resources facilitates dominant species during these times. Additional data is needed to determine if these trends are consistent over a longer study period.