62 • / February 2006

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n c ff f e Cleanup Crew ly it a s nd para Story by “The native are often In the second part of the project, The dung beetles heather smith thomas a little smaller. Some of the large they took the beetles out and planted completely eliminated horn fl ies in ones, like the ‘rollers’ that work on alfalfa in both tubs. the manure.” top of the ground, are not native. “In both tubs the alfalfa sprouted, A good population of dung beetles Dung beetles spend their lives Several were imported from Africa but the plants died in the tub that can effectively control these fl ies, he in manure. Adult beetles use liquid on a USDA (U.S. Department of had never had beetles,” Clymer says. says, because even though the beetles contents of manure for nourishment ) program,” Clymer says. “They measured growth of the plants may only be active a few months of and lay their eggs in balls of manure “Our native dung beetles are good, and did soil analysis, and there was a the year, it is during the same time (brood balls) that they bury; hatching but not quite as effi cient as those major difference.” the horn fl ies are active. larvae consume most of the brood from Africa.” Clymer’s interest in dung beetles ball. Clymer explains that there are has been focused fi rst on reducing Other benefi ts Parasitologist Bill Clymer, three kinds of dung beetles: fl y populations and internal parasites The benefi ts of dung beetles, Amarillo, Texas, has spent his career and, second, on pasture improvement besides reduction in harmful Dwellers. Dwellers live in the dealing with parasites. He through fertilization and eliminating parasitism, include increased forage manure pat itself. They don’t tunnel says dung beetles are some of our best nongrazed areas. availability, reduction of manure under it, nor do they take the manure allies for controlling parasites that runoff during storms or spring thaws, somewhere else. Dwellers lay their depend on manure as part of their life Horn fl y control increased water retention in soil, eggs in manure and help shred the cycles. They also remove and bury Dung beetles are used in Australia enhanced root penetration by plants, manure. Birds come along and break manure, which helps fertilize the soil to control horn fl ies, Clymer says, and more nitrogen (N) recycling. up the manure pat as they look for and reduce accumulation of manure pointing out research showing that In most pastures, there is tall grass beetles. on top of the ground. beetles bury 95% of the horn fl ies where or horses leave manure Rollers. Rollers, or tumblebugs, and 90% of the internal parasites in piles, Clymer points out. “I used to are larger — about the size of a The beetles manure. think grass grew taller there because thumbnail. Not often seen in the “Some are host-specifi c. One manure pat, without dung of nutrients from the manure, but northern states, these beetles cut out In Australia, there are some that beetles, can generate 60-80 adult it’s because the don’t want to a little ball of manure, lay an egg in only feed on kangaroo . There horn fl ies. Environmentally, long- graze next to their own manure,” he it and roll it away by pushing the ball are tiny beetles that feed on rodent term control of fl ies is better says. In fact, the only time they will with their hind legs. They may bury droppings. In Africa, the achieved by degrading the dung pats graze it is when there is nothing else it 200 feet away from its original spot. dung is as large as my fi st,” where immature fl ies develop than by left in the pasture, he adds. Tunnelers. The third type of Clymer says. “The manure pile from sporadically applying toxic chemicals. “Not only do you lose the grazing beetle is a tunneler, which digs below an elephant weighs 80 to 150 pounds. And, using dung beetles for fl y area where horse or cattle manure is the manure pat. You may not see a I’ve seen those piles gone within 24 control eliminates problems with sitting, but also an area with about change in that pat until you kick it to 48 hours, being worked on by resistance to chemical controls such an 18-inch radius around it. Those or bump it; then you’ll fi nd there’s these large dung beetles.” as insecticide ear tags. rough areas continue to expand if you nothing there but the external surface. In the , beetles that Dung beetles are attracted only to don’t have dung beetles,” he says. If Sometimes they excavate a place to feed on cattle manure also feed on fresh manure, which is where horn dung beetles get rid of the piles, this put manure in the ground, so there horse manure. These beetles are not fl ies come and where the eggs from creates more available pasture area may be fresh soil pushed up around active in colder months, but in warm internal parasites will be, he explains. the animals will graze. the edges or up underneath the shell. regions they are active year-round. A high percentage of horse and cattle One pastured produces There are many native species and Clymer summarized a science parasites are inactivated or destroyed 12 fecal piles per day or 4,300 fecal others that have been imported. project in which two South Dakota by beetle activity. The tunneling piles per year. Manure may take 5%- Several types of beetles were 4-Hers put the worst soil they could and burying disrupts the parasites’ 10% of an acre’s available grazing imported during the 1970s and 1980s fi nd (from a gravel pit) in two plastic life cycles. Even if the eggs hatch, area. If no manure is recycled into into North America and Australia. tubs — one with dung beetles and the young parasites can’t reach the the soil, one animal can remove 2.5 These continents did not have one without. Each day for three ground surface. acres of productive grazing area. A extensive livestock populations weeks, the 4-Hers put fresh “Several years ago I was doing herd of 50 cows can render 129 acres in early times. Some species manure in both tubs. horn fl y research in south Texas with unproductive in one year. followed bison herds in early “The tub with dung beetles ear tags,” Clymer said. “A fl ight of Dung beetles can offset this years, but native species have kept ‘using up’ the manure,” dung beetles moved in, and we had loss tremendously. An adequate not been able to keep up Clymer says. “But, they had to do the study over again because population of beetles can bury 90% with our increased livestock to keep taking out old manure my control group (those with no of manure on pastures within a week. production and manure. from the other tub.” insecticide tags) all went to zero. By contrast, the absence of dung February 2006 / • 63 beetle activity may mean manure will pesticides, dung beetles can move in from remain on pasture for 16 weeks to a year surrounding areas. Some species can fl y up unless it is mechanically broken up. to 10 miles. They can repopulate the area, “The tunnelers are the most but it may take several years. benefi cial,” he says. “They bury the Also, if you only use an avermectin manure, aerating soil and fertilizing dewormer once a year, or maybe in “Even though dung beetles may not it. Their activity helps water percolate the spring and fall, there are several completely eradicate manure, when they down into the soil.” months during summer when beetles can crawl through it they help mites and bacteria Their actions also help reduce reproduce. disperse through the pat to help break it contamination of water sources, Clymer down,” parasitologist Bill Clymer says. says. Up to 70% of the nitrogen in manure is lost if it isn’t buried. If manure is buried, the water runoff won’t wash it away into streams. “A rancher in southern Oklahoma who has 400 mother cows says dung beetles bury a ton of manure a day on his ranch,” Clymer says. “This makes a good, natural fertilizer.” Dewormers, pesticides may hinder beetles “The USDA did a study in 1981 and discovered that dung beetles at that time were worth over $2 billion dollars to our agriculture economy — everything from burying feces to increased grazing areas and putting more nitrogen into the soil, reducing parasitism and improved control of pest fl ies,” Clymer says. There’s increasing interest in dung beetles, and some livestock producers want to make sure they don’t disrupt beetle populations with pesticides. Sometimes our attempts to control parasites may hinder nature’s way of dealing with them. Cattle producers who have diligently used certain deworming/ delousing products fi nd the manure buildup in their corrals and pastures is more than it was in earlier years. Some types of dewormers and pesticides destroy dung beetles. “Use of avermectins (Ivomec®, Dectomax®, Eprinex® and generic forms), which are macrocyclic lactones, will eventually decimate dung beetle populations due to lethal activity against the larval stage,” Clymer says. “By contrast, Cydectin® and Quest®, which contain moxidectin, are a little different. They are macrocyclic lactones also, but that family tree splits. You have the avermectins on one side and the milbemycins on the other. Quest and Cydectin are milbemycins, which is moxidectin.” Avermectins do not kill adult beetles, but are 64 times more toxic for immature stages of some species than the milbemycins, he says. If avermectin is used on cattle at label rates to control parasites, no dung beetle offspring will emerge, he explains. “The manure pat is attractive to beetles when it is fresh — up to about three or four days. Dung beetles will work in it for several days,” Clymer says. “If you use an avermectin dewormer, immature dung beetles may be killed from 10 days to more than six weeks. The time frame for toxicity depends on species of beetle and the specifi c product used. That means every manure pat that’s dropped in that period will be toxic to immature beetles.” What if you’ve inadvertently killed off the local dung beetle population? If you stop using the dewormers or