- April 10, 2018 - Insectarium : Champions of nature, Insect diversity
Rhinoceros beetles rank with the most spectacular insects on the planet. They are researched, collected, studied, venerated. But for all that, they remain largely unknown.
Rhinoceros beetles have always filled us with wonder. When Charles Darwin saw a horned beetle of the genus Chalcosoma for the first time, he was moved to write:
“From the small size of insects, we are apt to undervalue their appearance. If we could imagine a male Chalcosoma, with its polished bronzed coat of mail, and its vast complex horns, magnified to the size of a horse, or even of a dog, it would be one of the most imposing animals in the world.”
InAsia, these beetles exert a true fascination: they turn up in both comic strips and TV series! There are even certain areas where fights are organized, with the winners “earning” considerable amounts of money.
Lifting 2 kg
The Amazonian Kayapo people regard the Hercules beetle (Dynastes hercules) as the chief of all insects. In fact, thanks to its musculature and its horns, the powerful beetle can lift as much as two kilograms. It’s a symbol of protection, strength and virility. And in some tribes, only the important men in the village may wear beetle-head necklaces, proof of their special significance.
A subfamily of fighters
Rhinoceros beetles belong to a special beetle subfamily, the Dynastinae, about 1,500 species of which have been determined. Among the Dynastinae one tribe stands out through the exceptional development of its horns: the Dynastini (11 genera and about 50 species), or “true rhinoceros beetles,” some of which reach17 centimeters in length.
Among the Dynastini, sexual dimorphism is very marked. The male has horns on the head and thorax, while females generally have none at all, or else very small ones that resemble a tubercle.
Most of the adults, who are nocturnal, feed on ripe fruit or sap. The horns are used primarily in fights between males to gain access to females. But it’s believed that males might also use them to scrape away at tree trunks in order to get at sap.
A little known life
The life cycle of these beetles is well known. Male and female spend long hours mating. The female then lays dozens of eggs in a compost made up of decomposing wood, leaves and humus. Small C-shaped larvae (typical of beetles) hatch and feed for a number of years before producing a shell in which the larvae will turn into pupae and then into adults.
But where precisely do they live? And for how long? Do they feed on anything else in nature? How do they find a partner? So many things remain to be discovered about the ethology of these big beetles.
A new species
Recently, at work on identifying a large series of horned beetles of the genus Golofa in Peru, Dr. Brett C. Ratcliffe of the University of Nebraska and Stéphane Le Tirant of the Insectarium de Montréal discovered a new species, Golofa limogesi, which they named in honor of René Limoges, technician at the Insectarium de Montréal.