The oriental latrine fly Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) as a new forensic indicator in SW Europe.

The oriental latrine fly, Chrysomya megacephala (Fabricius, 1794), is a potential forensic indicator in Mediterranean countries due to its first report in southwestern Europe in 1998. It was first recorded in Alicante (southeastern Spain) and is expanding across the Iberian Peninsula. Until now, this synanthropic species of forensic importance had been captured in baited traps and on pig carcasses in Europe, but never on human corpses. After reviewing all cases studied at the Institute of Legal Medicine of Alicante and the National Institute of Toxicology and Forensic Sciences in Madrid, C. megacephala was recorded for the first time in seven Spanish cases. The identification of material collected during autopsies revealed its scarcity compared to other species in the sarcosaprophagous Diptera community. In all cases, C. megacephala larvae coexisted with thermophilous necrophagous blow fly Lucilia sericata. Other coexisting species included the calliphorids Calliphora vicina and Chrysomya albiceps, and the muscid Synthesiomyia nudiseta. Chrysomya megacephala was collected in various coastal localities in Spain, particularly along the southern and Mediterranean coasts. Most cases shared common characteristics, including the time of year (summer), domestic indoor habitats, and the decomposition stage (active decay). The relevance of these findings is discussed in relation to the importance of taxonomy in identifying this exotic species and its role as forensic entomological evidence in Europe. Given the impact of climate change, the species composition and biology of the sarcosaprophagous Diptera community, particularly in the Mediterranean basin, must be continuously studied and reviewed.