Chasing Young Females Saves Male Black Widows from Certain Death

Arachnologists have uncovered a mating tactic between black widow spiders that helps the male of the species avoid death after sex.

A new study, published Tuesday in the journal Biology Letters, describes an adaptive mating method used by the male Black Widow spider in choosing immature females to impregnate. Typically, a mature male Black Widow spider is killed and eaten by the mature female after impregnation, a natural phenomenon known as copulatory cannibalism, "a model example of the extreme effects of sexual selection."

Unlike mature females, immature females of the species are too young and small to kill their mate, but still have functioning reproductive organs.

This way "males can increase their reproductive success by copulating with […] immature females after piercing the female's exoskeleton to access her newly developed sperm storage organs," according to the spider scientists.

Male Black Widow spiders who succumb to copulatory cannibalism are obviously monogamous. But this newly-discovered strategy allows males to be repeat offenders. "Although successful only during a brief period before the female's final moult, males may employ this tactic when they associate with [immature] females in nature," the study states.