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No. 52: Jul-Aug 1987

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Parasites Control Snail Behavior

A species of estuarine snail bearing the larvae of the trematode parasite Gynae cotyla adunca behaves radically different than it does when not infected. It lets itself become stranded high on beaches and sandbars, where it becomes easy prey to crustaceans living in this region. These crustaceans serve as the parasite's next host. Somehow, the parasite is able to modify the snail's behavior in a way that enhances its own chances for success. The question, as always in such cases, is how? And if it is a chemically induced change in behavior, how did it evolve?

(Curtis, Lawrence A.; "Vertical Distribution of an Estuarine Snail Altered by a Parasite," Science, 235:1509, 1987.)

Comment. Is present human behavior, thought by some to be irrational or suicidal, controlled by some unrecognized parasite that will ultimately benefit? Someone must have written a science fiction story on this theme.

From Science Frontiers #52, JUL-AUG 1987. 1987-2000 William R. Corliss