Seasonal abundance of carrion beetles (Coleoptera) as a potential forensic tool

Seasonal Abundance of Carrion Beetles (Coleoptera) as a Potential Forensic Tool.

Araceli Rosillo and Sibyl R. Bucheli

Abstract

Carrion beetles are important members of the ephemeral ecosystem of decomposition. They are dependent upon the carcass for both food and breeding. The common name refers to several diverse families of beetles including Silphidae, Scarabaeidae, Dermestidae, Trogidae, Histeridae, and Staphylinidae. Although carrion beetle diversity is well understood in North America, there are still large gaps in our knowledge including regional studies of seasonal abundance and intraspecific niche partitioning. This study focuses on the abundance of carrion beetles during spring, summer, fall, and winter in the Pineywoods ecoregion of southeastern Texas. A fresh carcass is placed outdoors in a cage every week to observe beetle frequency and diversity. Each carcass is checked five days out of every week for fifteen minutes per day. As the seasons progress from spring to fall, species composition of carrion beetles changes (i.e., certain species are found during certain seasons). The results indicate that there is a difference in beetle presence throughout the months. This study has important forensic implications: a better understanding of carrion beetle activity can allow forensic entomologists to create a more precise timeline of beetle occurrence, which can be used to estimate the time since insect colonization of a cadaver.