Weed & Pest
Dung beetle populations can save ranchers big bucks on the range
Kearney, Neb. – Some of the latest research taking place at the University of Nebraska is studying the effectiveness of dung beetle populations on rangeland. The presence of dung beetles has proven to be an effective method of fly control.
According to Sean Whipple, a post doctorate research associate at the Panhandle Research and Extension Center, research shows that the presence of dung beetles on grazing land can save U.S. ranchers an estimated $380 million annually, based on yield loss, pesticide applications and fertilizer use. Whipple said health costs and environmental problems from pests and pesticides are not included in this cost.
Approximately 7,000 species of dung beetles exist worldwide, Whipple recently told a group of over 300 ranchers during the Nebraska Grazing Conference in Kearney, Neb. Some species of dung beetle can be found on every continent, except Antarctica, but they are most diverse in Africa, where more than 2,000 species exist.
In fact, Whipple said dung disappears overnight there, because the beetles are so aggressive.
“In some areas, they will even ride on the animals in anticipation of the dung,” he added. “They will ride on it until the animal defecates, then they will jump off into the dung.”
In the U.S., Whipple sees great potential in not only cost-savings but also in a healthier environment with the presence of dung beetles.
“Every cow will drop 10 to 20 dung pats per day,” Whipple explained. “Each dung pat covers 0.82 meters square and can last up to four years on rangeland without being degraded or weathered. Animals won’t graze in proximity to their own dung. In fact, they will avoid up to two meters around the dung pad.”
He estimated that dry, old cow chips can cover rangeland and available forage up to the equivalent of five to 10 percent per acre per year.
“It would be to our benefit to remove those pats with dung beetles to increase the amount of forage we have available for our cattle,” Spangler noted.
In addition, when the dung beetles consume the pats, they cause nutrient cycling, which causes direct carbon and nitrogen sequestration that can reduce gas emissions. If the pat is removed within 48 hours, it can reduce carbon emissions in the atmosphere by 80 percent, he added.
The main thrust of Whipple’s research has focused on the presence of dung beetles for fly control.
“No one wants to see face flies, horn flies or stable flies on their livestock,” he said. “Yet, dung is a breeding ground for flies and other pests. A single pod can produce 100s of flies in one night. In Australia, over 100 adult bush flies can emerge from a 1,000 cubic centimeter (cc) dung pat, and that 1,000 cc dung pat can produce 3,000 flies in its lifetime.”
In the U.S., over $800 million is spent every year on fly control. It is a cost that dung beetles can do for free, Whipple said.
“If producers have an adequate population of the dung beetles on their property, they could see a 95 percent reduction in pests and flies,” he commented.
The beetles will not only feed on the dung, but they also eat the fly eggs, creating healthier livestock and reducing costs related to veterinary pharmaceutical treatments.
Inhibiting dung beetles
An estimated 56 percent of cattle in the U.S. are treated with insecticides, like Ivomectins, to control internal parasites.
“Injectables like Ivomectins go through the animal and end up on the range,” Spangler explained. “If it is meant to inhibit growth of the fly, it will also inhibit growth of the dung beetle,” he said. “It can inhibit dung beetle production for up to 30 days.”
Some products can even reduce survival and be fatal to the dung beetle populations. Whipple said treatments should be in the form of dusts or sprays and applied when the dung beetle population is inactive.
Grazing directly influences the number and species diversity of the dung beetles present on the range, due to the congregation of cows.
“The more the cows congregate, the more species will be present,” Whipple explained.
The population of dung beetles is also equivalent to the amount of dung present. The beetles rely on fresh dung that is wet and moist. Once the dung develops a crust, it doesn’t appeal as much to the beetles, he added.
Whipple said his current research is focusing on how dung beetles work as agents of bio-control on rangeland based on the cattle diet.
The beetles do have some feeding preferences. Through his research, Whipple said he hopes to be able to answer how attractiveness of dung to dung beetles, pest flies and parasites varies based on livestock diet quality and how grazing strategy impacts dung beetle abundance and species diversity.
In 2014, Whipple will be conducting research at the University of Nebraska-Lincoln Barta Brothers Ranch in the eastern Nebraska Sandhills.
This research will look at transport of nutrients by dung beetles, optimal grazing strategies for dung beetle conservation and the role of dung beetles in nutrient cycling depending upon the type of grazing strategy used.
“Conservation of the dung beetle is essential to the ag community,” Whipple stated. “There is no negative impact of the dung beetle. Range management directly impacts their performance.”