TECH

male spiders catapult each other after mating

published Monday, April 25, 2022 at 8:47 pm

In some species of spiders, males have a compelling reason to run away soon after intercourse.

A team of Chinese scientists has found that “Philoponella prominens” males catapult themselves immediately after mating to avoid being killed and eaten by their partner.

Spiders use two of their legs to propel themselves in a split second, leaning on the female. This technique was first described by a study published Monday in the journal Current Biology.

To make this discovery, the use of high-speed, high-resolution cameras was required, the lead author of this work, Shichang Zhang, of Hubei University, told AFP.

Researchers were studying sexual selection in this species, which lives in communities of up to 300 individuals.

Of the 155 matings observed, the male was then catapulted away in 152 cases, thus surviving the encounter.

The three non-pushing males were quickly captured, killed and eaten by their partner.

And 30 males that researchers prevented from catapulting suffered the same fate. Scientists then concluded that this mechanism was essential to escape female sexual cannibalism.

Males can mate up to six times with the same female, jumping away, returning through a braided wire, then mating and walking away again.

The jumps performed were impressive, with an average maximum speed of 65 centimeters per second and acceleration equivalent to 20 G, or 20 times the acceleration felt in free fall.

In the air, spiders spin around 175 times per second.

According to Shichang Zhang, females judge the sexual attitude of males by their ability to escape.

“With the catapult, a male can escape the female’s sexual cannibalism and the female can choose a performing male, because the kinetic performance could be directly related to the physical condition of the male,” he explained.

Spider females have the ability to retain sperm deposited by a male, and decide whether or not to use it to fertilize their eggs.

Therefore, according to Shichang Zhang, females can ultimately only accept sperm from males who successfully catapult themselves. In the future, she wants to investigate whether there really is a link between these leaps and mating success.

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