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Wednesday, April 25, 2007

ANIMAL TRACKER

Oil beetle


* Japanese name: Hime tsuchihanmyo
* Scientific name: Meloe coarctatus
* Description: A handsome (at least I think so) shiny black beetle, with long legs and an elongated body, which unusually has short elytra (wing covers) that expose most of the abdomen. In most beetles, the hard wing-cases completely cover the abdomen, but the oil beetle -- also called the blister beetle (for good reason) -- has a different method of protecting itself. The body is some 2 cm long. If you see a swollen appendage on the front pair of legs, that means it's a male.
* Where to find them: From Honshu to Kyushu, in gardens, parks, grassland and woodland. Flowers are a good place to look, but be careful if you find one (see below).
* Food: The adults feed on flowers and the leaves of various plants, such as amaranths, daisies, sunflowers, legumes and nightshades. The larvae, however, are insectivorous -- they enter the nests of wild bees, and attack the developing bee larvae. How do they get into a bees' nest? They lurk by flowers, and cling to the legs of visiting bees, so hitching a ride to the nest. Once there, they then eat larvae and pollen stores. They may also eat grasshopper eggs.
* Special features: If you startle an oil beetle, it will play dead. If you -- or a bird or other predator -- nevertheless try to touch the insect, you might get a shock. In the beetle's blood is a poisonous chemical called cantharin that squirts from the leg joints and causes blistering of the skin (hence the beetle's other name). Cantharin also has another function: When they mate, the male transfers the chemical to the female, who uses it to cover her eggs to protect them from predators. Two hundred years ago, a French entomologist discovered (don't ask me how) that cantharin is a kind of terribly painful aphrodisiac. If a man consumes it, it causes a 4-hour erection. But there is nothing pleasurable about this: the swelling is caused by irritation of the urinary tract. Some dubious wart-removal products contain the blistering chemical, too.

PHOTO COURTESY OF BIO-IMAGE NET



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