Wary male spiders woo lifelessly

Certain male spiders confront the threat of a cannibalistic female with a novel tactic: They play dead while having sex.

Nursery spiders (Pisaura mirabilis) belong to a family known for violent females that, on occasion, attack and eat males attempting courtship, notes Trine Bilde of Århus University in Denmark.

Biologists already knew that males of this species have one method for lowering the risks of romance: They show up with a gift of food. For example, the courting male might bring his intended a fly carefully wrapped in spider silk. The suitor holds the gift in front of him in his mouthparts.

But Bilde and her colleagues have noticed an additional trick. They report in the March 22 Biology Letters that in 51 observed courtships, almost half the males suddenly “dropped dead.”

Not brain-dead, that is. Even when keeled over, a male kept his gift between him and his sweetheart.

Such fainting spells sometimes struck males during their first approaches to females and sometimes, if the female grew restless, during actual mating. Typically, the female then shifted her attention from the motionless male to the snack. When she settled down to eat, the male came back to life and to mating.

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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