Insects (Diptera) associated with cadavers at the Institute of Legal Medicine in Pernambuco, Brazil: implications for forensic entomology

Abstract

Increasing rates of unsolved homicides in Brazil prompt the need for applied entomological data to be used as a complementary tool by criminal investigators. In that context, we analyzed the occurrence of forensically important insect species (Order Diptera) on 14 cadavers taken into the Institute of Legal Medicine (ILM), in Pernambuco, Brazil, according to the conditions of the body and the pattern of colonisation by insects. Simultaneously, we surveyed the diversity of insects in the surrounding environment using bait traps. Five species were present on cadavers: Chrysomya albiceps, Chrysomya megacephala and Cochliomyia macellaria (Calliphoridae), Oxysarcodexia riograndensis and Ravinia belforti (Sarcophagidae). A total of 4689 adult insects belonging to 24 species of seven dipteran families (Calliphoridae, Sarcophagidae, Muscidae, Fanniidae, Phoridae, Anthomyiidae and Stratiomyidae) was collected at the ILM premises. C. albiceps was the most frequent species on the corpses and the most abundant in the traps. Species referred to as of forensic importance, such as Lucilia eximia, Chrysomya putoria, Oxysarcodexia modesta and Ophyra chalcogaster were collected on traps, but not on cadavers. There seems to be a limited colonisation of cadavers at the scene of the death, despite the ubiquity of necrophagous species in the area. The results contribute to differentiate between species that are involved in decomposition and those found in and around the mortuary installations of the ILM, thus providing potential clues about the locality of death and the post-mortem interval.