Calliphoridae Community Composition in Sunlit and Shaded Areas during Early Colonization in Metro Vancouver, British Columbia

Abstract

Necrophagous insects, particularly some species of blow fly (Diptera: Calliphoridae), are extremely useful in medico-legal entomology, as they colonize a body very shortly after death, if conditions are appropriate. Their species and development rates can be used to estimate their tenure on the body and so infer minimum time since death. As many blow flies have specific geographic and seasonal ranges, as well as habitat preferences, their presence on a body can also be used to infer whether a body has been moved from the original death scene. This study focused on the preferences for bait in sunlit or shaded areas. Eighteen beef liver-baited traps were deployed weekly at three sites, equally between sunlit and fully shaded areas. Eight species of blow fly were collected with the dominant species being Lucilia illustris (Meigen), L. sericata (Meigen), Calliphora vicina Robineau-Desvoidy and Calliphora latifrons (Hough). There was no difference between Calliphora spp. between trap placements, but Lucilia species were collected more frequently at sunlit sites, although statistical differences were only seen with L. illustris. Higher numbers of all insect species were collected in sunlit traps. This study indicates necrophagous insect preference, or lack thereof, for carrion sites and is important in determining which species may indicate a specific habitat.