Indoor decomposition study in Malaysia with special reference to the scuttle flies (Diptera: Phoridae)

Scuttle flies (Diptera: Phoridae) are a diversified insect group of forensic importance. Their frequent presence on human corpses indoors and in concealed environments can be the sole indicators to estimate the minimum post mortem interval (PMImin). However, bionomics of scuttle flies on decomposing animal carcasses are rarely documented indoors. The objective of this research is to observe and document the occurrence of scuttle flies on decomposing animal carcass placed inside a portable cabin maintained at room temperature (≈25.0 °C) in Bangi, Malaysia. This study was conducted in two rounds for a period of 40-day each and samplings were carried out in different intervals. Adult scuttle flies were aspirated directly from the carcass and preserved in 70% ethanol. Their larvae and pupae were reared until adult stage to facilitate identification. Megaselia scalaris (Loew), Megaselia spiracularis (Schmitz) and Dohrniphora cornuta (Bigot) were the scuttle flies found on the carcasses with M. scalaris being the earliest and dominant to colonize the body. This cosmopolitan species proved to be the best indicator to estimate PMImin indoor but in the increased presence of other fly species, it might be relegated to a secondary role. The scuttle flies were also found to coexist with other dipterans of forensic importance in an indoor environment, mainly Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae). This information expands the knowledge on the bionomics of scuttle flies on decomposing animal remains indoors.