The creatures that scuttle across your kitchen floor may have fascinating qualities, writes Ellen Bartlett
It is spring, and the young beetles fancy is lightly turning to thoughts of love, or at least of mating.
Tok-tokkies tenebrionid beetles of the genus Psammodes are drumming their abdomens against the soil.
Bark beetles are rubbing various parts of their bodies together (its called stridulation, and the purpose is to make noise). Like the sirens on the rocks, the knock-knock of the tok-tokkies, and the shrill of the bark beetles is irresistible to other tok-tokkies and bark beetles that is.
Male death watch beetles are banging their heads against the wall, not because they are frustrated, but because female death watch beetles like it that way.
For those who think of beetles as bugs, ugly anonymous things scuttling over the kitchen floor, it is time to reconsider. Their love lives alone reveal complexities of motive and behaviour that far exceed the low opinion most humans hold of them.
Take the flashers. Fireflies, also known as lightning bugs, are neither fly nor bug, but beetles belonging to the family Lampyridae. Using the enzyme ATP (adenosine triphosphate) and oxygen, they produce light with near-100% efficiency , compared to the incandescent bulb, which gives off 90% of its energy as heat. They use the light to find lovers.
The males initiate the ritual by flying around, sending out signals in patterns, like tiny airborne lighthouses. Females signal back. So it goes.
As in many love stories, there is a tragic element. Predatory females of the genus Photuris put their bioluminescent powers to an unsavoury use. They mimic the mating signals of unsuspecting males, lure them close and then eat them.
Some female beetles have opted for life without sex. Parthenogenesis development of offspring from an unfertilised egg is common practice among certain species of weevil. They were cloning long before Dolly the sheep was a twinkle in a scientists eye.
These are only a few examples of goings-on in the beetle world .
For those who want to know more, Arthur Evans, director of the insect zoo at the Natural Museum of Los Angeles County, California, and Charles Bellamy, curator of the department of Coleoptera at the Transvaal Museum in Pretoria, tell all in a book they have co-authored.
The title is from a quote attributed to the British scientist JBS Haldane. Asked what could be inferred about the work of the Creator from a study of His works, he is said to have replied that He had an inordinate fondness for beetles.
With or without divine interest, for the last 240-million years members of the order Coleoptera have been fruitful, and they have multiplied. More than 350 000 different species of beetles have been described, making Coleoptera the largest order of animals in the world. Beetles represent 20% of all living organisms, a quarter of all animals.
They far outnumber the more famous African fauna. If you look at the total number of vertebrates in southern Africa, you count all of the fish and the birds and reptiles and mammals, its under a thousand animals, says Bellamy in an interview in his Transvaal Museum office, which he shares with the museums collection of several hundred thousand buprestids, or jewel beetles. You come to the beetle department, and we can give you five to ten times that amount, just for beetles.
Beetles range in size from the .035cm long Nanosella in the eastern United States, to Titanus giganteus of northern Brazil and French Guiana, which grows to 20cm, larger than the human hand. Beetles inhabit nearly every biological niche from the narrow fringes of polar ice caps to the broad, unexplored expanse of rain forest canopy from arid and inhospitable deserts, to the lava tubes in the icy caves of Montana.
For all that, a lot less has been written about the beetle than say, the lion. And it really is not fair.
For one thing, beetles are beautiful. Jewel beetles, which are the focus of Bellamys work, are aptly named for they come in all colours, dazzling mixes of metallic golds and blues and greens, of neon yellow and jet black. Jewel beetles are used as jewelry in some cultures. In the Yucatan of Mexico, Megazopherus chilensis is decorated with glass beads, tethered to a chain, and pinned to clothing, alive.
Beetles could also teach us a thing or two about self-defence. Horned beetles boast the most impressive array of natural offensive and defensive weaponry seen on earth. Leaf and long-horned beetles are experts in chemical warfare.
Charles Darwin wrote of the Atlas beetle that were it magnified to the size of a dog or horse with its polished bronze coat of mail and its vast complext of horns … it would be one of the most imposing animals in the world.
Darwin was an avid beetle collector. He once recalled encountering three rare beetles on one tree and since his hands were full he put one of them in his mouth.Alas, it ejected some intensely acrid fluid which burnt my tongue so that I was forced to spit the beetle out.
Beetles are the ultimate biological success story. The secret of their success, the authors say, is in their body form, and in their reciprocal interactions with plants a you-scratch-my-back-and-Ill-scratch- yours relationship that has served them well for 240-million years.
When beetles first appeared, during the lower Permian period, no one was eating fungi. So the beetles ate fungi. When flowering plants appeared, 125-million years ago, they ate them. As the plants adapted to keep from being eaten, the beetles adapted, too, and continued eating.
Beetles that didnt eat plants, ate animals. Those that didnt eat either, ate dung.
Dung beetles, of which there are many varieties in South Africa, are a breed apart, not only because they look like earth-moving equipment in miniature with shovel-like forelegs, scrapers on the head and thoracic scoops but also because of how they benefit us.
They are the ultimate recyclers. Since ancient times these seemingly industrious creatures have been observed carefully cutting, shaping, rolling and burying pieces of animal excrement, the authors say.
Dung beetles are one of the most beneficial and least appreciated of all insect groups … If not for the role played by carrion and dung beetles, we would soon be overwhelmed by filth and death.
Some dung beetles are generalists, flying long distances in search of faecal material suitably aged and of the right consistency; others are specialists. The Central American Uroxys gorgon, for example, attaches itself to the fur of its preferred dung source, the three-toed sloth.
The dung beetles are a good example of the flexibility of Coleoptera, of the beetles ability to adapt to changing circumstance.
The body adaptations that beetles exhibit reveal a remarkable collective ability to reconcile their needs to a continually changing environment, the authors say. These highly specialised bodies have permitted beetles to occupy a staggering array of habitats with relative ease.
For example, aquatic beetles have hydrodynamic bodies and built-in vertebral keels for stability on the water. Mormolyce phyllodes, the fiddle beetle, is compressed so flat it can hunt for insects in the narrow space between the bark and wood of decaying trees.
For all that the book tells its readers about beetles, there is much more to be learned. For one thing, no one really knows how many beetle species there are out there.
Among the coleopterists who have hazarded a guess is Terry Erwin of the Smithsonian Institution. In 1982, extrapolating from data collected in Panama, Erwin estimated there are more than eight million species of beetles in the tropics alone.
The urgency of the task is in part to determine what there is out there before it is gone.
The continuing devastation of huge tracts of tropical forests and other poorly known habitats by chain saws, bulldozer and bonfires lends urgency to the question, the authors say. How many species of beetles are we losing every year?
The same problem exists here. Vast tracts of southern Africa are uncharted beetle territory. Bellamy wants to set up a regional network of rural beetle collectors, to add to the Transvaal Museums already considerable collection at about 1,2-million specimens, it is Africas largest and to add to existing knowledge about the Southern African environment.
This data is more important than just a bunch of beetles in boxes, he says. We want it to be used in an interpretative way…
People know about common things, but they have no concept of the great diversity. We actually hope to use beetles to market the concept of biodiversity, because they are, as we have said, the essence of it. There is nothing that is more diverse.
ENDS