A certain species have taken paternity security to the next level: after copulation, the male would mutilate a female's genitalia.
According to a study published in the Current Biology, researchers found that male spiders of the Larinia jeskovi, an orb weaving spider, mutilates their female counterparts' gentialia after mating to prevent remating with other male spiders.
"Competition between males and their sperm over access to females and their eggs has resulted in manifold ways by which males try to secure paternity," the researchers explained in their study.
To further study this process, researchers caught wild orb-weaving spiders of both genders then allowed them to mate under observation. Once the male is mounted on a female, the study team used blasts of liquid nitrogen to freeze them in the middle of the act. Once successful, the locked together species are studied microscopically for a closer look at their genitalia.
Reconstruction of the spiders' copulation by micro-CT scanned images revealed that the male spider removes the scapus from the female genitalia after coupling. The scapus is necessary for the mechanical process of mating to happen.
After the mating season, the female spiders researchers caught were all found lacking of their scapuses afterwards.
"In the orb-weaving spider, males remove the scapus, a crucial coupling device on the female external genital region," wrote the researchers, who were from the Zoological Institute and Museum at the University of Greifswald in Germany, in their report.
They added that it was also possible that at least 80 other species of spiders could also be doing the same form of mutilation and paternity security to their mates.
The researchers called this mutilation a widespread but overlooked phenomenon, though they also speculate that this may not be as bad as it looked.
Interestingly, female spiders are known to be able to store sperms for years, making it possible for them to produce offspring continuously even after having just one partner for the rest of her life.
Different species of spiders often have their own ways of securing mates and driving competition away, such as males fiercely guarding the females, making their mates unattractive to other male spiders and by sealing the female's reproductive organs with a plug.
But it is not just the male who can be strangely possessive or morbid. The black widow spider, for instance, is known for getting its name for feeding on its male counterpart after mating.
However, experts also said that this ritual isn't as prevalent as it initially appeared, as studies have also shown that this only happens in about 60 percent of the cases and that some male black widow spiders were even found living in the female's web without coming to harm.