Why Everyone Should Love Dung Beetles
Ro Wauer, June 1, 2003, The Victoria Advocate, © 2003
Most "bugs," especially those closely associated with dung, face an up-hill battle for respect, much less appreciation, by the majority of human beings. Yet, dung beetles are not only fascinating to watch, they also are extremely important to a healthy soil, by recycling our natural resources. And a healthy soil serves as a cornerstone for the well being of the majority of our native plants and animals.
Dung beetles, also known as scarab beetles, tumblebugs, or "poop-rollers," are fascinating creatures. Our North American species are seldom more than an inch in length, although one African species that processes elephant dung is 2.5 inches long. All are dark-colored beetles, sometimes shiny and brown, green and orange, or black in color, with club-shaped antennae. They possess a sort of brush-like sieve mouths, for slurping wet dung. Males often possess a horn or toothlike projection on their back. Dung beetle's appearance is one that only another dung beetle can truly appreciate.
Although dung beetles are commonplace in healthy soil communities, they are seldom noticed. But when they are noticed, they usually are seen going about their work in a very business-like way, rolling manure into balls, sometimes larger than themselves, and rolling the balls across the terrain (often a considerable distance) to underground tunnels constructed by both male and female beetles. Malcolm Beck and John Howard Garrett, in "Texas Bug Book," state that "This is the only known case among insects where the male aids in providing for the young."
Female dung beetles lay a single egg in each dung ball that serves as both an incubator and food source for the larvae. Once a tunnel is filled with dung balls, the tunnel, that may be more than 18 inches deep, is back-filled, and the adults fly off in search of fresh treasure. New adults eventually dig their way out and immediately begin their search for fresh manure. They usually over winter in the soil as larvae inside brood balls.
Watching one or a pair of dung beetles rolling dung can be fascinating, especially when they are struggling across a terrain filled with obstacles. They walk on their front legs, going backward, using their hind legs to guide their treasure. It is obvious that dung beetles love dung. As ecologist Pat Richardson wrote, "They slurp it, haul it, roll it, fight about it, and bury it...They don't bite or spit or sting. They simple live, eat, sleep and dream dung." However, there is a good deal to learn about the importance of dung beetles. Researchers have discovered that dung beetles "will bury a ton of wet manure per acre per day and remove 90 percent of the surface material... A horse pad can disappear underground in 24 hours, leaving only a soft fluffy layer of undigested plant material."
In a dung beetle fact sheet, Pat explains the immediate benefits of dung beetles on pasture and rangeland thusly: by "reduced fouling of available forage, breaking life cycle of pest flies and internal parasites (those whose eggs or larvae incubate in dung), improved soil aeration, increased soil organic matter, nitrogen and moisture, increased water infiltration in soil (reduced erosion and flooding), removal of non-point source pollution from the watershed, and improved soil foodweb health (in turn producing healthier vegetation). On pasture and rangeland, we routinely measure double and more often triple water infiltration rates where dung beetles have buried a cowpat."
She also points out that a colleague "estimated than an adequate population of dung beetles on pastures throughout the USA could save cattle raisers two billion dollars annually just from increased grazing, improved nitrogen recycling, reduced parasitism and reduced pest flies." Today's pastures and rangelands often lack dung beetles, due principally to the use of insecticides and parasiticides.
The story of the lowly dung beetle is a fascinating one, and demonstrates better than most the value of each and every creature within our world. Even the lowest and less obvious has a fascinating life history, and one that often is extremely beneficial to our long-term health and survival.