More good descriptions of parasitic bugs from Zimmer:

If you keep a vegetable garden, there's a fair chance you'll encounter a grisly sight this summer. Some poor catepillar will be clutching a leaf, with the pupae of parasitic wasps sprouting off its back. It has just died in a most grotesque way. A wasp has zeroed in on the catepillar and injected eggs into its body. The eggs hatched, and the larvae devoured their hosts from within, keeping it alive until they were ready to emerge.

What makes this sight all the more grotesque is the fact that the plant the catepillar is sitting on may have been an accomplice to the crime. When catepillars nibble on plants, the plants sometimes respond by releasing a distinctive cocktail of chemicals. This odor then attracts parasitic wasps. The plants are not just releasing a sort of chemical scream. Wasps are very precise in the species of catepillars they choose, and they can tell these odors apart.

The post is really about a new article in PLoS Biology which suggests that the caterpillars also pick up the wasp-attracting chemicals, and cleverly avoid eating the plants at times when they are likely to emit those particular chemical signals.

Someone should let me know if I'm the only one who thinks this weird bug stuff is neat.

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