This female praying mantis is finishing up the last tasty bits of the male that just mated with her. In the lead article in tomorrow’s science section of the New York Times, I talk to scientists who study females of some species that sometimes devour their mates. Sexual cannibalism is not common, but it is revealing. The evolutionary forces that shape the sexes can drive them into some extreme conflicts, even turning one sex into a meal for the other. In some cases, males actually become partners in their own demise–passively or complicitly. A new study indicates that male praying mantises are not so willing. They can tell when females are hungry, and they take extra precautions.

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