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  4. 1997
  5. November

Dung Beetles

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Dung Beetles are biological control agents for horn flies and intestinal parasites. According to Dr. Truman Fincher, Entomologist at Texas A&M University, ranchers spend over 800 million dollars per year in controlling these pests of livestock. Horn flies and internal parasites complete their life cycle in dung pats. Female horn flies lay eggs in fresh dung and in five to seven days adult flies emerge. Internal parasite eggs are excreted with the animal dung and in one to two weeks the egg will hatch into a larvae stage. Larvae will migrate to the tip of grass plants. When a grazing animal bites the grass, then the parasite returns to the gut of the animal.

Dung beetles, in high populations, will bury dung pats four to six inches in one to three days. This destroys the habitat for other insects and internal parasites to complete their life cycle. This fact was well demonstrated by Dr. Truman Fincher at a field day on the Walt Davis Ranch located south of Bennington, OK. He set up a demonstration the day before by putting a high population of dung beetles into a wire cage set over a fresh dung pat. Another dung pat was positioned beside the caged beetles to test the native population of dung beetles in burying the dung. The following day both dung pats were gone. In fact, the native population was large enough to do the job better than the caged beetles, which was a surprise to Dr. Fincher.

Many years ago, Walt had changed to holistic management whereby he was using a cell grazing system and high stock density of 6 to 7 cows per acre. He also stopped using any chemicals for pest control. He began to see dung beetle populations soar. Dung beetles have kept his pastures clean. Both internal and external pests are not a problem to his livestock as he reported to the field day participants.

Other holistic management practitioners have reported the same effects when they change to cell grazing and stop using internal parasites control chemicals with long lasting residues. (Please note: A report by K. Kruger and C. H. Scholtz in a recent publication of the Journal of Agriculture Ecosystems and Environment, on lethal and sublethal effects of ivermectin on dung beetle breeding stated that treated cattle supressed the development of the dung beetle E. intermedius for 28 weeks after injection.)

Dung pats contain carbon and valuable soil nutrients. Dung is a food source for soil microflora (fungi, bacteria, and actinomycetes), protozoa, and earthworms. For the dung to be of value, it must be incorporated into the soil profile. Dung beetles are nature's way of recycling carbon and minerals back into the soil to be further broken down into humus for plants. If dung stays on the soil surface and dries, 80% of the nitrogen is lost into the atmosphere.