Death, flies and environments: Towards a qualitative assessment of insect (Diptera) colonization of human cadavers retrieved from sites of death in Brazil

Abstract

Empirical data on decomposition ecology have long established blowflies (Calliphoridae) and flesh flies (Sarcophagidae) (Diptera) as the most frequent colonizers of carrion, especially at early stages of decomposition. However, the scarcity of studies based on human cadavers has hindered inferences about colonization of homicide victims in real case scenarios. We describe here a survey of insects associated with cadavers retrieved from the site of death in Northeastern Brazil, with emphasis on the association between species diversity and the surrounding environment. We examined 81 cadavers, most of which were of men and resulting from violent death. Twelve cadavers (14.8 %) contained insect larvae, which were reared in the laboratory until adult emergence and identification. Ten species of Diptera effectively colonized the cadavers; seven of Family Calliphoridae - Chrysomya albiceps (Wiedemann, 1819), Chrysomya megacephala (Fabricius, 1794), Chrysomya putoria (Wiedemann, 1830), Cochliomyia macellaria (Fabricius, 1775), Hemilucilia segmentaria (Fabricius, 1805), Lucilia cuprina (Wiedemann, 1830), Lucilia eximia (Wiedemann, 1819) and three of Family Sarcophagidae, Blaesoxipha (Gigantotheca) stallengi (Lahille, 1907), Microcerella halli (Engel, 1931) and Peckia (Sarcodexia) lambens (Wiedemann, 1830). The species C. albiceps and C. macellaria were the most frequent colonizers, while Sarcophagidae was reported in only four cases. Insects were present on cadavers found in urban (n = 8) and rural (n = 4) sites, outdoors (n = 6) and inside (n = 6) residences. Presence of larvae was more frequent in the natural orifices in the head (n = 11). Clothing did not prevent from ovi/larviposition for most species. We present the first register of B. stallengi colonizing human corpses and expand the knowledge on the geographical distribution of necrophagous insects. Our protocol may contribute to forensic entomology in areas exposed to fast decomposition, such as the Neotropical Region.

Keywords: Blaesoxipha; Blowflies; Chrysomya; Cochliomyia; Forensic entomology.