The thankless labor of a tumble bug, or dung beetle, can make your pasture more productive.

If there is anything to reincarnation, most of us would not wish to come back as a dung beetle. Dung beetles (or "tumblebugs," as some call them) spend their entire lives in and around fresh manure.

Their unappetizing habitat notwithstanding, dung beetles lead industrious and useful (and short) lives. They belong to the scarabaeidae (scarab) beetle family, and there are thousands of different species worldwide-more than 90 species in North America.

Dung beetles feed mostly on the manure of large herbivores, such as cattle and buffalo. With nearly 65 million beef cattle on U.S. pastures, tumblebugs shouldn't be going hungry. Consider this: One pastured adult bovine produces 10 to 12 manure pats each day, or more than 4,000 per year.

There are two main types of dung beetles. Most are "tunnelers," which dig tunnels under a manure pat and move the manure into underground chambers. The other group (made up of species such as Canthon pilularius) are the "rollers" or tumblebugs, which form manure into a sphere, then roll it some distance from the manure pat and bury the manure ball from 8 to 30 inches deep.

Dung beetles usually work as a male/female pair. The female lays a single egg inside the manure brood ball. Heat from the decomposing manure incubates the egg, and the dung beetle larvae feed on the manure. In 2 to 4 weeks, the larvae pupates. Then the young adult beetle emerges and digs its way to the surface and flies off in search of a mate and fresh cow manure.

"For country boys growing up in pre-television days, watching tumblebugs was a source of entertainment," said Forrest "Doc" Pugh, Cabool, Mo. "In fact, they are still more entertaining than most of the crap on TV."

Aside from their entertainment value, dung beetles provide several agricultural and environmental benefits. Some studies show that, under ideal conditions, dung beetles can bury 85 to 90 percent of the manure in a pasture within a week.

It's common knowledge that cattle reject grass re-growing in a fecal pile and for some distance around it. If the dung is not recycled into the soil, these "rejection zones" can take

5 to 10 percent of the pasture area out of use by cattle for a considerable time. To the extent that dung beetles remove and spread manure more widely, they enhance forage availability and grazing efficiency.

"Manure is a breeding ground and incubator for horn flies and face flies, two economically important pests of cattle," said Michelle Thomas, formerly with the National Center for Appropriate Technology at Fayetteville, Ark. "As dung beetles feed, they compete with the fly larvae for food and physically damage the flies' eggs. Fly populations have been shown to decrease significantly in areas with dung beetle activity."

The tunneling of dung beetles increases the soil's ability to absorb and hold water, and their manure-burying activities also enhance soil nutrient cycling. A high population and variety of dung beetle species can remove a complete manure pile from the soil surface within 24 hours, which reduces the threat of water contamination from non-point source pollution.

Unhappily, dung beetle larvae are susceptible to some insecticides used for fly and internal parasite control in cattle; especially those systemic products that act as a larvicide in the manure.

"Dung beetle populations declined for several years, but now some species appear to be rebounding somewhat," said Wayne Bailey, extension entomologist, University of Missouri. "We're not sure whether the beetles have developed resistance to some veterinary pesticides, but numbers seem to be increasing."

Some products, such as Cydectin (moxidectin), appear to be more "beetle friendly" than others. Such fly controls as backrubbers, ear tags and occasional sprays have less effect on dung beetles.

"Another option is to treat cattle during the cooler months of the year, as dung beetles and larvae are inactive then," said Thomas. "Better yet, before treating cattle for internal parasites, take a fecal sample to your veterinarian to do an egg count to help determine the parasite load."

Controlled grazing systems can be managed to increase dung beetle populations and varieties, she added. "Concentrating the manure in smaller areas reduces the time beetles must spend in search of food," Thomas added. "Grazing cycles that match the reproductive cycle of the dung beetles are best, as cattle are returned to a grazing cell at the same time new adult beetles are emerging from the soil."

The life cycle of a dung beetle takes as few as 6 weeks, or may take up to several months. Researchers at several U.S. locations are importing new dung beetle species from Africa and Australia, and studying how well they perform in North America.

If you aren't sure dung beetles are on the job in your pastures, watch the length of time it takes for manure pats to disappear. If they remain intact for more than a few days, it's likely your dung beetle population is low-or non-existent. It may be profitable to adopt management practices that encourage dung beetles.

After all, dung beetles work for free and apparently love their thankless work.