(Washington) In some species of spiders, the males do have a valid reason for running away immediately after sex.
Posted at 2:51 p.m.
A team of Chinese scientists have found that male ‘Philoponella prominens’ catapult themselves immediately after mating, in order to avoid being killed and eaten by their partner.
The 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 and high-resolution cameras was necessary, explained to AFP the main author of this work, Shichang Zhang, of Hubei University.
The researchers were studying sexual selection in this species, which lives in communities of up to 300 individuals.
Of 155 observed matings, the male then catapulted away in 152 cases, thus surviving the encounter.
The three males that did not propel themselves were quickly captured, killed and eaten by their partner.
And 30 males that the researchers prevented from catapulting themselves suffered the same fate. The scientists thus concluded that this mechanism was essential to escape the sexual cannibalism of the females.
Males can mate up to six times with the same female, leaping away, returning through a woven thread, then mating and moving away again.
The jumps performed were impressive, with a maximum speed of 65 centimeters per second on average, and an acceleration equivalent to 20 G, or 20 times the acceleration felt in freefall.
In the air, spiders spin about 175 times per second.
According to Shichang Zhang, females judge the sexual aptitude of males precisely by their ability to run away.
“By catapulting, a male can escape the sexual cannibalism of the female, and the female can choose a performing male, because kinetic performance could be directly correlated to the physical condition of the male,” he explained.
The female spiders have the possibility of keeping the sperm deposited by a male, and of deciding whether or not to use it to fertilize their eggs.
Thus, females may ultimately only accept sperm from males that successfully catapult themselves, according to Shichang Zhang. In the future, he wants to study whether there is indeed a link between these jumps and mating success.