Science & Technology

These male spiders catapult away to keep away from sexual cannibalism

An act of acrobatics retains males of 1 orb-weaving spider species from changing into their mates’ post-sex snack.

After mating, Philoponella prominens males catapult away from females at speeds as much as practically 90 centimeters per second, researchers report April 25 in Current Biology. Other spiders leap to seize prey or keep away from predators (SN: 3/16/19). But P. prominens is exclusive amongst spiders in that males soar by the air to keep away from sexual cannibalism, the researchers say.

P. prominens is a social species that’s native to nations corresponding to Japan and Korea. Up to 300 particular person spiders can come collectively to weave a complete neighborhood of webs. While finding out P. prominens’ sexual habits, arachnologist Shichang Zhang and colleagues observed that intercourse appeared to all the time finish with a catapulting male. But the motion was “so fast that common cameras could not record the details,” says Zhang, of Hubei University in Wuhan, China.

High-resolution video of mating companions clocked the male arachnids’ velocity from round 32 cm/s to 88 cm/s, the researchers report. That’s equal to simply beneath 1 mile per hour to almost 2 mph.

A male Philoponella prominens spider avoids being eaten by a feminine after intercourse by leveraging hydraulic stress to increase leg joints and fling himself away, seen right here first at about one-fiftieth precise velocity after which at regular velocity.

The leap appears to be like somewhat like the beginning of a backstroke swimming race, Zhang says. Males maintain the information of their entrance legs towards a feminine’s physique. The spiders then use hydraulic stress to increase a joint in these legs, shortly launching a male off a feminine earlier than she will be able to seize and eat him.

Of 155 profitable mating rituals that the researchers noticed, 152 males catapulted to survival. The remaining three that didn’t fell sufferer to their accomplice. Female spiders additionally ate all 30 males that the group stopped from leaping to freedom with a paintbrush.

These male orb weavers in all probability acquired their leaping talents to counter females’ cannibalistic tendencies, Zhang says. The spiders’ leap to survival is a “fantastic kinetic performance.”

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