Dung beetle (Onthophagus) preference for different mammalian dung in Northwest Iowa

Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) feed on feces of other animals and use the dung to house and feed their larvae. Dung beetles provide ecosystem services and are beneficial to the livestock industry. By mixing dung into the soil, they aerate and change soil properties such as pH and nutrients. Efficiently moving dung into the soil removes breeding ground for livestock pests and allows areas to return to pasture that would otherwise be covered in manure. Losey & Vaughan (2006) estimated that dung beetles save the cattle industry alone $380 million per year. Pesticides (including those used to treat livestock) and heavy grazing can hurt dung beetle populations. Four transects of four dung-baited pitfall traps were placed in a restored tallgrass prairie at Iowa Lakeside Laboratory in Northwest Iowa. The surrounding landscape is row crop agriculture, forest remnants, housing, and West Lake Okoboji. Dung collected from local farms was frozen until being placed in traps. Over August 1 through 4, 2021, the bait and beetles were replaced and collected daily. We collected 2 species, Onthophagus hecate and O. pennsylvannicus. Both are common in much of the US and have been documented in 54 and 24 of Iowa’s 99 counties respectively. Other Scarabaeinae were collected and are in the process of being identified. Both species had a significant (p < 0.01) preference for horse and pig dung over bison and cattle dung.