Comparative fly species composition on indoor and outdoor forensic cases in Malaysia

Forensic entomology refers to the science of collection and analysis of insect evidence in order to determine the minimum time period since death. This study aimed to investigate the occurrence of forensically important flies on 34 human remains referred to Universiti Kebangsaan Malaysia Medical Centre over a period of three years. Entomological specimens were collected at the death scenes and/or during autopsies. Live specimens were reared into adults while preserved specimens were processed for species identification. Five families, seven genera and nine species of flies were identified from human remains. The results of the study showed Chrysomya megacephala (Calliphoridae) maggots occurred on corpses with the highest frequency (70.6%), followed by Ch. rufifacies (Calliphoridae) (44.1%), sarcophagid fly (Sarcophagidae) (38.2%), Synthesiomya nudiseta (Muscidae) (20.6%), Megaselia scalaris (Phoridae) (14.7%), Lucilia cuprina (Calliphoridae) (5.9%), Ch. nigripes (Calliphoridae) (5.9%), Eristalis spp. (Syrphidae) (5.9%) and Hydrotaea spinigera (Muscidae) (2.9%). The greatest fly diversity occurred on remains recovered indoors (eight species) compared to outdoors (three species). Whilst, single and double infestations were common for both indoor and outdoor cases, multiple infestation of up to six species was observed in one of the indoor cases. Although large numbers of fly species were found on human remains, the predominant species were still those of Chrysomya, while S. nudiseta was found only on human remains recovered from indoors. The present study provides additional knowledge in the context of Malaysian forensic entomology and the distribution of forensically important flies which is of relevance to forensic science.