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Friday, Oct. 5, 2001


Praying mantis

* Japanese name: Okamakiri mushi * Scientific name: Tendora sinensis * Description: This is a big, alien-looking insect, either green or brown, with large eyes and powerful legs. It gets its English name from the way it stands for hours on end, front legs folded as if in prayer. But the Japanese name describes the insect more aptly: "Kamakiri" is the cutting action a scythe makes. Okamakiri is the largest and the most common of nine species in Japan, growing from 70-90 mm long. They are winged and can fly short distances. An old, quite primitive group of insects, they are related to cockroaches and stick insects. * Where to find them: Adults are active from August to November, in woodlands and parks from Hokkaido to Kyushu. They can often be seen, standing motionless, on bushes and hedges. In May, baby mantids -- miniature versions of the adult -- hatch from their egg case. As they grow, they go through six or seven nymph stages before they become adults. * Food: Mainly other insects. The mantis is a sit-and-wait predator. When it spies its victim, perhaps a grasshopper or a cricket, it lashes out its front legs and impales the prey on sharp spines. Some larger species (there is one in Sri Lanka that reaches 250 mm in length) have been known to attack lizards and frogs. * Special features: Like spiders, mantids are an example of animals in which sex is dangerous. In spiders, the female often eats the male after sex -- but in mantids, the female might eat the male before sex. In about 10 percent of sexual encounters, the female mantid attacks the courting male as he approaches her, bites his head off and then devours his body. Copulatory behavior is controlled by a neural ganglion in the abdomen, so even when the head is bitten off, copulation can proceed normally. The male mantis does not need his brain to have sex. The female can produce a larger egg case when she has been feeding well, so it makes sense for her to eat the male mantis. Biologists think that it may also make evolutionary sense for the male to donate his body -- but only if she uses his sperm to fertilize her eggs. Mantis sex is a tricky business.

Neural ganglion: A mass of nerve cells outside of the brain.

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