Mallory A. Hagadorn, Kaitlyn Mitchell, Joseph Restein, Dana L. Price
The Coleopterists Bulletin 75 (2), 382-402, (27 October 2021) https://doi.org/10.1649/0010-065X-75.2.382
KEYWORDS: agriculture, Chemicals, non-target fauna, Scarabaeinae, Aphodiinae
Cattle treated with chemicals to control parasites can fecally excrete residues that have the potential to adversely affect local assemblages of dung beetles (Coleoptera: Scarabaeidae). Using 200-m transects and dung-baited pitfall traps, we compared the dung beetle communities on 19 cattle farms in Maryland, USA where pests and/or parasites were controlled with chemicals (CU, n = 9 farms) or where no chemicals were used (NCU, n = 10 farms). Traps were baited once a month with fresh cattle dung from each location. We collected a total of 31 species comprising 12,380 dung beetle specimens. The five most abundant species, Onthophagus taurus (Schreber), Onthophagus pennsylvanicus Harold, Onthophagus hecate (Panzer), Blackburneus stercorosus (Melsheimer), and Labarrus pseudolividus (Balthasar), accounted for 85% of the total individuals sampled. No difference was found when comparing total abundances of dung beetles sampled from NCU and CU farms. There was, however, a consistent significant effect of month across multiple dominant species. Using Random Forests analyses, we determined site location, soil type, and chemical lethality as additional important predictor variables affecting dung beetle abundances on Maryland farms. Present-day management practices implement a broad spectrum of chemical usage. Our work examines this variability to facilitate the understanding of factors currently affecting the biodiversity and abundance of beneficial dung beetles.