Tying up your lover is one way to introduce a little excitement to the bedroom. But for male nursery-web spiders, bondage during mating can be a matter of life and death. By restraining their partners, male spiders reduce their chances of falling victim to sexual cannibalism, a new study finds.
Nursery-web spiders (Pisaurina mira) are long-limbed hunters that catch and overpower their prey. Though the females' bodies can be a bit larger than males', measuring about 0.5 to 0.7 inches (12 to 17 millimeters) in length, researchers noted that males' legs were longer than females', relative to their body size.
Prior studies described the male spider's unusual mating behavior - wrapping silk around the female's legs before and during copulation - and the scientists wondered if longer legs would help males restrain their hungry mates, leaving the guys more likely to survive cannibalism sparked during the throes of passion. [Animal Sex: 7 Tales of Naughty Acts in the Wild]
In some insect and spider species, sex can be a deadly roll of the dice for males, carrying the possibility that their female partners may suddenly identify them as a convenient postcoital snack. While this is understandably not an ideal outcome for males, cannibalizing is "quite beneficial for the female," said Alissa Anderson, who co-authored the study.