Canadian Journal of Arthropod Identification

Key to Forensically Important Piophilidae (Diptera) in the Nearctic Region

CJAI 27 -- January 22, 2015

Sabrina Rochefort, Marjolaine Giroux, Jade Savage and Terry A. Wheeler


| Abstract | Introduction | Materials & Methods | Identification Challenges | Checklist | Key to Piophilidae | Acknowledgments | References | PDF | Cite |

Identification challenges in the Piophilidae

The key to the world species of Piophilidae by McAlpine (1977) remains the most complete work for the identification of adults even though several new species have since been described (Soós 1977, McAlpine 1978, McAlpine 1989, Ozerov 1989, Ozerov & Barták 1993, Bonduriansky 1995, Merz 1996, Ozerov 2000, 2002, 2004, 2007, Martín-Vega 2014, Rochefort & Wheeler 2015) and additional distribution records are known based on museum specimens. McAlpine’s (1977) key is not ideal to identify piophilids in forensic studies as it includes many non-forensically important species and is mostly based on colour differences which can be troublesome in this family due to intraspecific colour variations. Such polymorphisms have been documented in several species of forensic interest such as Parapiophila atrifrons (Melander & Spuler) (Rochefort & Wheeler 2015), Parapiophila vulgaris (Fallén) (McAlpine 1977) and Prochyliza nigrimana (Meigen) (Martín-Vega & Baz 2011). Some species are also morphologically very similar. In southern Europe, for example, the very similar Piophila casei (L.) and Piophila megastigmata McAlpine co-occur; this can cause identification errors that may lead to erroneous PMI estimations (Martín-Vega 2011). Confusion between P. megastigmata and P. casei has occurred in forensic research (e.g., Prado e Castro 2010), a mistake that might actually be widespread in the field (Prado e Castro et al. 2012), and we suspect that such confusion may also apply to other species pairs in the Nearctic.

Some forensic studies limit Piophilidae identification to the family or generic levels (e.g., Schoenly et al. 2007, Voss et al. 2008, Velasquez et al. 2010, Bygarski & Leblanc 2013) or identify the material as Piophila casei, despite the fact that several species have been documented in forensic literature worldwide (Table 1). Piophila casei is a well-known, cosmopolitan, synanthropic species and was the first piophilid documented in forensic studies (Megnin 1894). This may account for the possibility that Piophilidae collected in forensic studies are frequently identified (or misidentified) as Piophila casei (see Martín-Vega 2011).