The beetles fly slowly with their bodies in a near-vertical position, McCullough found. Cutting off a male's horn moved his center of mass only about 1.7 percent.Īnd in flight, the horns made no difference at all. Because of their low mass, they hardly affected the beetles' center of mass. They comprised only 0.5 percent to 2.5 percent of body weight. The horns turned out to be very dry and hollow, McCullough said. Finally, she tested the beetle bodies in a wind tunnel to see how the horns affected the drag on the beetles' bodies and thus the force they'd need for flight. She also determined the center of mass of the beetles with and without their horns.
After euthanizing the beetles, she weighed them with and without their horns. To evaluate the cost of the beetles' horns, McCullough tested Asian rhinoceros beetles ( Trypoxlus dichotomus), which have horns about two-thirds as long as their bodies. Flashy body parts often do in fact, scientists theorize that wild feathers or other elaborate mate-attracting devices send a signal that says, "Mate with me! I'm so healthy I can support a totally useless appendage!" McCullough and her colleagues expected those weapons came at a cost. The larvae can damage plant roots, and the 62-mm (2.4-inch) adults live under rotting bark.Two male rhinoceros beetles lock horns in battle. tityus) is another rhinoceros beetle found in temperate regions. One European species, Oryctes nasicornis, has rear-pointing horns.
The male possesses a single upright horn the female has only a small tubercle. The American rhinoceros beetle ( Xyloryctes jamaicensis) is a dark brown scarab a little more than 25 mm (1 inch) long. Shorter, conical horns project forward from each side of the thorax. The male’s head sports a long central horn that is split. Another striking specimen is the 13-cm (5-inch) elephant beetle ( Megasoma elephas) of the lowland rainforests in Central and South America. The upper horn curves forward from behind the head, whereas the lower emerges from the head itself. Found in American tropical forests, these two species have double horns that are oriented vertically. neptunus) are spectacular, resembling an enormous pair of pincers. The Hercules beetle and rhinoceros beetle ( D. Some species, such as the Hercules beetle ( Dynastes hercules), can grow to more than 18 cm (7 inches) long, of which 10 cm (4 inches) may be horn. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
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