Some male spiders tie up females before sex so they don't get eaten alive

Spider cannibalism — the tendency for female spiders to eat their mates during or after sex — is fairly common knowledge at this point. There's a surprising evolutionary benefit to this copulatory suicide, too, as Ed Yong explained in National Geographic in 2016:

In 1996, Maydianne Andrade found that sexual encounters between redback spiders are longer if the male allows himself to be cannibalized.

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