Drawn into the decay: An extended two-summer examination of the effectiveness of Calliphoridae (Diptera) bait

There is significant variation in the distribution of Diptera that contribute to decomposition and are of forensic importance. To study this distribution, it is necessary to attract these species of Dipteran via artificial trapping methods. However, there is no definitive answer to the bait (lure) that should be used to collect the greatest quantity of Diptera that are of forensic importance nor the richest diversity. To understand the differences in baits for Diptera traps, over two summers, three butterfly traps were placed in three different areas of the USDA-ARS property in Kerrville, Texas in year one and a ranch in Fredericksburg, Texas the following summer. Traps were set in the morning and then collected at the end of the day. The specific baits used were beef liver and catfish filets in year one and ham hock, chicken liver, and 70%/30% beef the next. Diptera were also collected from roadkill for comparison. This was done thrice a week for six weeks in June through July 2022 and every day from July 3, 2023, to July 29, 2023. Eight Calliphoridae species were collected in the first year, including Cochiomyia macellaria, Lucilia mexicana, and Chrysomya rufifacies. In total, 697 dipterans were collected, 588 from fish-baited traps, nine from liver-baited traps, and 100 from roadkill. In year two, seven Calliphoridae species were collected, including C. macellaria, L. mexicana, and C. rufifacies. In total 463 flies were collected, 216 from chicken liver, 160 from 70%/30% ground beef, and 87 from ham hock.