Jennifer Scarlott informs Sanctuary Cub readers about the important role that dung beetles play in the ecological cycle.
Dear Cub kids,
Did you know that the soil under your feet comes from the stars above your head? That the dark line across the centre of the Milky Way is a line of dirt perhaps 65,200 light-years across, and 6.167x1017 km. long?
Yes, there are megatons of dirt out there, the detritus of ruined stars that float around the universe until it enters some force field. You’ve probably heard that humans are made of the elements of stars… that we are ‘stardust’. Well, in fact, everything is stardust, which is, ultimately, dirt!
A wonderful natural history writer named William Bryant Logan wrote a book called Dirt: The Ecstatic Skin of the Earth. Dirt’s ‘ecstasy’ comes from the fact that it is so alive, literally crawling with organisms and microorganisms. Earthworms, yes, but so much more, too.
Photo: Kirat Mundle.
Meet the marvellous dung beetle, a creature revered and worshipped by the ancient Egyptians. The dung beetle, known also as the scarab (Scarabidae), can be found all over the world, not just in Egypt, and there are thousands of known species. Found on all continents except Antarctica, dung beetles live in many habitats, including deserts, farmlands, forests, and grasslands.
Okay, but what about that name ‘dung’ beetle? Yes, this breed of Coleopterans (scientific term for the beetles’ group) live on dung! They search for it using their sense of smell. By the way, they prefer the dung of herbivores (animals that eat plants) to that of omnivores (animals that feed on plants and meat). After locating some dung, the beetle begins to roll it into balls so large and perfectly spherical that people occasionally mistake them for small cannonballs!
With the dung in a round shape, the beetles then roll it (usually males do most of the rolling, with females hitching a ride or walking alongside the male), to a spot of soft soil. There, the male and female stop, bury the ball (to protect it from flies and other interested parties), and mate underground. The female lays her eggs inside the ball. Some beetle species remain with the ball, to protect the offspring.
The larvae grow and develop inside the ‘brood balls’ (other dung balls are simply buried for later food retrieval), and feed on the decaying organic matter in the dung as they grow. When fully formed into the beautiful adult scarab, with iridescent wings, the creature emerges from the ground and begins life as a grown-up dung beetle. What the ancient Egyptians noted was that scarabs went into the ground with their balls of dung, and some months later, a new beetle would appear. This seeming miracle led to great reverence for these large beetles, which are depicted in countless beautiful ancient works of Egyptian religious and funerary (post death) art. In fact, when an Egyptian pharaoh died, his heart was replaced with a scarab made of precious lapis lazuli (semi-precious stone) – a symbol of transformation, renewal, and eternal life!
The lovely fact is that the dung beetle is an extremely important creature in the web of life. By burying and consuming dung, it improves nutrient recycling and soil structure. It protects livestock and other animals by removing dung that, if left above the surface, would provide a breeding ground for flies and other species that are troublesome to mammals. Ah, the ecosystem ‘services’ provided by Earth’s living systems, of which humans are so often unaware – according to the American Institute of Biological Sciences, dung beetles save the U.S. cattle industry an estimated $380 million per year by burying livestock dung. In Africa, scientists counted a record number of scarabs on a single mound of elephant dung – some 16,000! This gives you a sense of the enormous amount of dung buried in and regenerating the soil all over the world.
The soil fertilised by dung buried by our friend, the scarab, is far richer than soil fertilised by manure left on the surface. When left on the surface, nitrogen in the dung is released into the air – but buried underground, the nitrogen is released into the soil, creating moisture-holding humus ideally suited for holding roots. In a beautiful cycle, the grasses and other plants that grow in areas where dung beetles are busy are lush and delicious, leading to a healthy, well-fed population of herbivores, who provide lots of fresh dung, feeding a plentiful group of dung beetles, and the cycle goes round and round, creating and maintaining a healthy landscape!
Best thing of all about dung beetles? They were one of the first animals known to navigate and orient themselves using the Milky Way. Something to think about when you stargaze tonight.
First appeared in: Sanctuary Asia, Vol XXXV, No. 7, July 2015.