WASHINGTON - A type of caterpillar with a taste for escargot rather than the normal vegetable diet has been discovered in Hawaii. The caterpillar is the first ever observed to eat any kind of mollusk, researchers report in Friday's issue of the journal Science. Indeed, only about one-tenth of 1 percent of caterpillars eat anything but vegetables. Hyposmocoma molluscivora, however, will not eat the green stuff even when the caterpiller is starving, say Daniel Rubinoff and William P. Haines of the University of Hawaii, Honolulu. When these caterpillars come across a resting snail, they begin spinning silk of the type...