Blow flies (Diptera: Calliphoridae) are necrophagous insects which are attracted to decomposing remains. The presence and life stage of their larvae are an important factors in the estimation of the postmortem interval (PMI) during death investigations. The purpose of this study was to survey the blow fly communities present under two separate circumstances: first, in the pre- and early-operation stages of a new outdoor forensic research facility in Northern Michigan (FROST); and second, in the context of large vertebrate (Sus scrofa) decomposition in a freshwater aquatic system in Mid-Michigan. Eight blow fly species were collected at the Forensic Research Outdoor Station (FROST) from May-September with Phormia regina, Lucilia illustris, and Cochliomyia macellaria composing a cumulative 94.2% of the total collections. Month was a significant factor in the mean relative abundance of these major species. Two blow fly species were collected over the course of approximately one month during aquatic vertebrate decomposition with Phormia regina composing 90.5% of the collections. Time was not a significant factor in the mean relative abundance of the species collected, but larval length changes over this period suggested multiple oviposition events. The findings in these two studies provide new and important information which can be utilized by forensic entomologists in future research as well as by forensic science professionals during death investigations and related casework.
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