Slave-Making Queens; Amazing Animals; Exclusive Online Issues; by Howard Topoff; 6 Page(s)

In the animal world, both predators and parasites survive at the expense of other species. Nevertheless, they don't get the same press. I am besieged with mail containing pleas for money on behalf of wolves and killer whales, but I have yet to see a T-shirt with the slogan "Long Live the Hookworm." The problem is, of course, that humans associate a parasitic lifestyle with disease. Our perception is of a furtive organism that insinuates itself inside us and, unlike a decent predator, intends to destroy us ever so slowly.

But there exists a form of parasitism considerably less macabre. Social parasitism, as it is called, has evolved independently in such diverse creatures as ants and birds. A female cuckoo, for instance, lays her egg in the nest of another species, such as a warbler, and leaves it for the host to rear. The brown-headed cowbird does the same. Each bird has evolved so that it produces eggs that match those of its chosen baby-sitter.