Spider size matters: Small males are eaten

OXFORD, Ohio, Sept. 11 (UPI) -- U.S. scientists say they may have answered the question of why large female spiders often eat their small male sex partners: they are easy to catch.

Researchers say female spiders are voracious predators and consume a wide range of prey, which sometimes include their mates. A number of hypotheses have been proposed for why females eat males and now Miami (Ohio) University researchers Shawn Wilder and Ann Rypstra believe the answer may be simpler than thought: Males are more likely to be eaten if they are much smaller than females, which likely affects how easy they are to catch.

In one species of spider, Hogna helluo, the researchers found large males were never consumed, but small males were consumed 80 percent of the time.

In examining data on a wide range of spiders, Wilder and Rypstra said they discovered the size of the male relative to the female determines how often sexual cannibalism occurs in a species.

"We were surprised to find that such a simple characteristic, such as how small males are relative to females, has such a large effect on the frequency of sexual cannibalism," said Wilder.

The research appears in the journal American Naturalist.