Monday, April 25

These male spiders adopted an unusual strategy to survive sexual cannibalism

A male orb-weaving spider catapults off a female after mating. Survival could mean another chance to fertilize her eggs.

Rudyard Kipling famously observed in a 1911 poem that "the female of the species is deadlier than the male." He specifically cited female bears and cobras, but the sentiment would certainly apply to many species of spider, as some female spiders habitually consume the males after mating—a behavior known as sexual cannibalism. The males in one species of orb-weaving spider (Philoponella prominens) have adopted an unusual defense strategy, according to a new paper published in the journal Current Biology. They catapult themselves away immediately after mating in hopes of having another go before being eaten—often flying through the air too quickly for a common camera to capture the details.

This species forms colonies in which spiders have individual webs that are loosely linked to form a conglomerate web complex, according to the authors. These communal webs can house as many as 215 spiders, with a male-to-female ratio of about 1.5. The team surveyed 477 such communal webs in the field, noting that the female spiders rarely left their webs and then usually only if the conglomerate web was destroyed. But the male spiders went from web to web in search of mates once they reached full maturity.

And yes, the females proved to be particularly aggressive during the mating process, which often ended in sexual cannibalism. The male spiders who escaped that fate were able to catapult away quickly once mating had concluded. Male spiders usually produced a dragline anchored to the female's web during courtship, which remained in place while mating. Once the deed was done and the female spider moved to attack, the male spider pushed himself off the web and swung to safety.

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