Analysis of the successional patterns of insects on carrion in southwest Virginia.

Abstract

Studies of carrion-insect succession on domestic pig, Sus scrofa L., were conducted in the spring and summer of 2001 and 2002 in Blacksburg, VA, to identify and analyze the successional patterns of the taxa of forensic importance in southwest Virginia. Forty-seven insect taxa were collected in the spring. These were represented by 11 families (Diptera: Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, Piophilidae; Coleoptera: Staphylinidae, Silphidae, Cleridae, Trogidae, Dermestidae, Histeridae). In the summer, 33 taxa were collected that were represented by all of the families collected in the spring, except Trogidae. The most common flies collected were the calliphorids: Phormia regina (Meigen) and Phaenicia coeruleiviridis (Macquart). The most common beetles were Creophilus maxillosus L. (Staphylinidae), Oiceoptoma noveboracense Forster, Necrophila americana L., Necrodes surinamensis (F.) (Silphidae), Euspilotus assimilis (Paykull), and Hister abbreviatus F. (Histeridae). Occurrence matrices were constructed for the successional patterns of insect taxa during 21 sampling intervals in the spring and 8 intervals in the summer studies. Jackknife estimates (mean+/-95% confidence limits) of overall Jaccard similarity in insect taxa among sampling intervals in the occurrence matrices were 0.213+/-0.081 (spring 2001), 0.194+/-0.043 (summer 2001), 0.257+/-0.068 (spring 2002), and 0.274+/-0.172 (summer 2002). Permutation analyses of the occurrence matrices showed that the patterns of succession of insect taxa were similar between spring 2001 and 2002 (P = 0.001) and between summer 2001 and 2002 (P = 0.007). The successional patterns seem to be typical for the seasonal periods and provide data on baseline fauna for estimating postmortem interval in cases of human death. This study is the first of its kind for southwest Virginia.