Research Tracks Shrinking Beetle Populations

Research Tracks Shrinking Beetle Populations An at-risk insect population could spell problems for U.S. agriculture, and scientists are racing to learn more. “Dung beetles recycle livestock feces and incorporate those nutrients back into the soil,” says Wyatt Hoback, Professor of Entomology at Oklahoma State University.  “The beetles not only improve pastures by allowing grass to grow, but they also reduce pest flies (face flies, horn flies) and internal parasite worms found in dung.”  A clean field is critical, as cattle rarely feed within five to 10 ft. of their dung. A dung beetle can spread 20 times its body weight in cow feces in one night. Multiply that by a colony, and they can quickly clear an entire pasture, allowing the cattle to return to grazing. Standard livestock practices are shrinking dung beetle populations. “The beetles are impacted by pesticide use,” Hoback says. When dung beetles use the affected dung, they experience a reduced ability to reproduce, and fewer larvae survive to adulthood. “We’ve known about the negative impacts of Ivermectin (used for controlling internal parasites) for a long time and are now interested in the effects of pesticides used to manage flies.” This requires field research using baited traps in the dung beetle’s preferred habitat. Hoback’s team collects, sorts and counts beetles to better track the effects on different species. “We’re assessing dung beetle communities at the Tallgrass Prairie (bison and limited pesticides) and comparing them with various ranching practices,” Hoback says. “We’ve shown differences in the community abundance and the rates of dung breakdown when there are lower numbers of beetles. Now we’re continuing to generate information about the non-target effects of pesticides—dung beetles accidentally being killed—and on practices that increase their numbers.” Generally, the best way to increase dung beetle populations is to minimize insecticide use. “Dung beetles contribute over $380 million annually to U.S. livestock producers. Beef is the top agricultural commodity for Oklahoma,” says Hoback. “We want to keep dung beetles around and make sure they’re healthy to improve ranching profit and sustainability.” Contact: FARM SHOW Followup, W. Wyatt Hoback, Professor of Entomology, Oklahoma State University, Stillwater, Okla. 74078 (ph 405-744-9403; whoback@okstate.edu).

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