True Facts About The Dung Beetle | video
SUMMARY: A lovely blend of science, animals and humour, all rolled up into a short informative video.
Dung beetle, probably Neomnematium sevoistra, in dry spiny forest close to Mangily, western Madagascar.
Image: Axel Strauß, 2008 (Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic licenses).
Today's video focuses on the dung beetle, those insects in the taxonomic superfamily Scarabaeoidea. These insects share a fondness for feces, subsisting either partially or entirely on animal dung. Scarabs are coprophagists -- shit eaters. There are more than 5000 species of dung beetles, and although they are found on every continent except Antartica, nearly all of them occur in warmer and moister regions of the world. They devote their adult lives to locating, collecting and secreting away the dung of animals. Most scarabid species specialise on the dung of one or a few animal species, and they prefer the droppings of herbivores to those of omnivores, and both are preferred to the turds produced by meat-eating animals.
This specialisation has led to problems. For example, after cattle were introduced to Australia, parts of that continent were plagued by huge swarms of flies that laid its eggs on cow shit during the summer months. Since the resident dung beetles specialised on marsupial turds, cattle poop remained untouched and over the years, vast areas were transformed into a giant, nearly continuous cow pat. Taking advantage of this situation, flies rapidly grew into pestilential swarms. In the 1970s, 20 or so species of African dung beetles were introduced to deal with the problem, which then reduced the number of flies by as much as 90 percent.
Ancient Egyptians celebrated scarabs for their diligence and industry and indeed, a single elephant turd, which can weigh in excess of three pounds (roughly one-and-a-half kilos), is typically dispersed within just a few hours by tens of thousands of these insects. Even today, dung beetles are admired: for example, the New York Entomological Society uses a scarab in its logo, replacing its prized dung ball with the planet Earth -- make of that what you will (right).
Although some beetles simply drag away bits of fresh poop and deposit them in waiting subterranean chambers, many dung beetles form their prized poop into a ball, which they then roll away, pushing with their front legs and using their hind legs to hold the ball as it spins on an invisible axle. Some species work as a team, and in other species, the male does the poop-pushing whilst the female catches a ride on top.
After the dung ball has reached its burial chamber, the female lays one or more eggs inside (this differs between species, of course), and when the larva hatches, it is surrounded by dinner. In some species, the adults remain with the dug ball to protect their growing brood, a form of parental care.
Sometimes, dung beetles get lost, which is probably not difficult when standing on your front legs to push a dung ball around. When this happens, the beetle stops rolling, climbs aboard the dung ball and orients itself by observing the sun, moon and polarised light. At night, they orient themselves using the Milky Way -- making them the only animal (beside humans) to use the Milky Way to navigate [doi:10.1016/j.cub.2012.12.034].
This charming video shows us a little more about dung beetles:
Dacke M., Baird E., Byrne M., Scholtz C. & Warrant E. (2013). Dung Beetles Use the Milky Way for Orientation, Current Biology, 23 (4) 298-300. doi:10.1016/j.cub.2012.12.034
You may enjoy this excellent and charming book Merde: Excursions into Scientific, Cultural and Socio-historical Coprology by Ralph A. Lewin [Aurum Press Ltd, 2000; Amazon UK; Amazon US]. Chapter 12 deals specifically with dung beetles. This fact-filled book is amusing and educational and its chapters are just the right length for reading whilst perched atop the porcelain throne.
NOTE: this piece was slightly reformatted from the original, which was published on the Guardian.
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GrrlScientist is an evolutionary biologist, ornithologist and freelance science writer who writes about the interface between evolution, ethology and ecology, especially in birds. You can follow Grrlscientist's work on facebook, Google +, LinkedIn, Pinterest and of course, on twitter: @GrrlScientist