Fauna of flies (Diptera) on bones and emergence succession: Forensic implications in skeletal remains

Fauna of flies on pig carcasses and bones and their emergence succession were investigated in Hokkaido, Japan. A total of 55,937 flies consisting 23 identified species in 16 families was collected from emergence traps after removal of carcasses and emergence containers containing bones. In emergence traps, Lucilia caesar (Linnaeus) emerged earliest, followed by Hydrotaea ignava (Harris). Piophilid flies emerged 22-25 days later than L. caesar, and their emergence periods were prolonged. In emergent flies from bones, Piophilidae was the dominant family, comprising five species; Stearibia nigriceps (Meigen) was the most abundant, followed by Liopiophila varipes (Meigen) and Protopiophila latipes (Meigen). Stearibia nigriceps and L. varipes remarkably dominated in summer bones and overwintering spring bones, respectively. Piophilids emerged from all 11 types of bones; the thoracic spine significantly yielded the most numerous individuals in S. nigriceps. The developmental duration of larvae of S. nigriceps in bones was estimated to be 12-34 days after placement of carcasses in summer. Observations of overwintering bones showed that L. varipes and Centrophlebomyia grunini (Ozerov) overwintered in larvae inside of bones. The importance of examining piophilid larvae in bones and their potential forensic usefulness are discussed.