Insects can aid in legal investigations in several different ways, including how long remains have been present and if a body has been relocated. To be able to answer these questions, you first need an understanding of what carrion flies are present in an area and when. Blow flies (Diptera: Calliphoridae) are the most common initial colonizer of remains, being found in almost all terrestrial habitats, and arriving within minutes to remains. Information related to blow fly presence and abundance in Arizona is severely lacking with this information not being studied in almost 40 years. Additionally, Phoenix presents a unique environment in that it is extremely arid and hot in the summers and also experiences periods of torrential rain. Four traps baited with a different source were placed around the Arizona University West Campus weekly for 24 hours, for one year (June 2019- May 2020). We collected and identified 944 adult calliphorids which comprised eight species across four genera. Bait preference and species composition were analyzed. Lucilia sericata (Meigen) was the dominant species collected (61% of total capture) followed by Calliphora latifrons Hough and Lucilia mexicana Macquart (28% and 10% respectively). High temperatures (>40°C) resulted in no blow fly activity. This work is the first step in understanding the species composition in urban areas of Arizona as well as insect arrival times.
