Sexual cannibalism is an extreme form of competition between the sexes. In order not to be devoured, the males must therefore develop stratagems in order to escape a disastrous fate after mating. In a spider, the males catapult each other at impressive speeds at the end of a thread.
There are several mechanisms in the animal kingdom that allow individuals to perform very rapid actions. These concern, for example, the projection of part of their, such as the tongue in the chameleon, the jaw in the sharks, or the catapult of the whole individual. These actions are known to be associated with predation behavior but also flight from predators. There is, however, a very specific case in which animals catapult themselves to avoid their own congeners.
Sexual cannibalism involves the female devouring her mate before, during, or after mating
This is the case ofsex, a practice which is, for example, observed in mantises and spiders. the implies that the female devours her partner before, during or after mating. In order to escape this sad fate, the males of the species Philoponella prominens have developed the ability to propel themselves far, far away from the female they have finished mating with.
Survival is in the acrobatics
An international research team has published the analysis of this amazing escape behavior. During their study, the authors observed 155 matings and report that at the end of 152 of them, the males females and all survived. The three that did not escape were captured and eaten by the females.
The authors then stopped some males from running away after mating to determine how much of this was running away. For this, they placed small brushes about 2 mm long on theof 30 males who were unable to catapult themselves and were all captured and devoured by their respective partners. This finding is enough to horrify readers but unequivocally proves that catapulting is a behavior necessary for the survival of males of the species. P.prominens and that it conditions the number of sexual partners they have during their lifetime and therefore their reproductive success.
One of the elements of success of this ejection resides in the speed of the action. The authors thus indicate that if the average catapult speed of the male after mating is around 66 cm/s, the record speed of 88.2 cm/s was recorded for one of the males who was visibly holding on very hard to his life. The authors explain that males need their two front legs to perform thispropulsion; these are in fact bent towards the female during mating and suddenly relax when the male catapults himself.
A male catapulting from a female during copulation in high speed video (1500 fps) and in normal video (30 fps). © Shichang Zhang
Finally, the authors report that the males are attached to a silken thread that connects themof the female and that this allows them, when they catapult themselves, to reach this web. This return is in their interest because the male can then return to the female and mate with her again, up to six times. At the house of P.prominensso as not to lose your head in the game of love, it is better to be ready to take… the big leap.