Inject your partner poison

Make up is a risk sport. That they tell the male of the religious mantis who has to feel how His head is devoured by the female While his body, automatically, continues to copulate. This practice is less common than what is thought, since it occurs in just a handful of Mantis speciesbut it is not the only stage of the animal kingdom in which The male is killed for the good of the offspring. And there is A hops They have the same customs.

Of course, there is an octopus of a concrete species that has a strategy to fertilize the female and survive the process: poison it.

Dimorphism. Something important before entering the case of octopus is that there are many animal species with cases of sexual dimorphism extremely accentuated. This implies a difference in size between the sexes, being the case of the mantis one of them. In mammals, males are usually larger than females, since they are the ones that fight for territories and mating, but it occurs backwards in case of raptors, arthropods, amphibians and reptiles.

In the octopus, there are extreme cases in which there are females that are up to ten times larger than males. One of those cases is that of the blue line octopus –Hapalochlaena fasciata-. They are small, but tremendously lethal octopus because they are able to inoculate a very powerful neurotoxin that they share males and females. Contrast with its small size: just bigger than a golf ball.

Sex and snack. However, the female is twice as large as the male and mating dynamics is not very healthy to say (for the male, of course): due to that imbalance, the female usually ends the life of her sexual partner during the process. However, in a study published in Science Directa group of researchers from the University of Queensland in Australia has discovered that the male has developed a toxic way of surviving mating, literally.

Due to that huge difference in size, males cannot develop tactics that they use in other species of octopus, such as a more elongated reproductive arm to inseminate at a safe distance or even arms – character – with the reproductive load that emerges so that the animal can flee. The only thing left to this species is to bite the female to inject neurotoxin, directly.

Here we have a complete half -hour sequence:

Poison. As we read in Sciencealertresearchers comment that, probably, this evolution has been “an answer both to the need for reproduction and protection”, and what they do is ‘bite’ the female before trying to copulate. They do it near the aorta, injecting the fair amount of tetrodotoxin to paralyze their partner during the process.

To check, the researchers placed six couples in different aquariums and observed this practice in all cases. “The females succumb quickly,” they comment, and it is something they observed because they lost reflexes to light stimuli, paid and the pupils contracted due to the loss of nervous system control.

Wait, what happened? They also made more precise observations: while the males went from 20 or 25 contractions per minute at rest at 35 or 45 during the intercourse, the females not only suffered an abrupt fall in their heart rate, but stopped breathing completely after about eight minutes of the bite.

They point out that none died, so the amount of neurotoxin they inject is very precise or, evolutionarily, the female has developed countermeasures, but the bite on the back of the head was evident. “Once immobilized, males proceed to intercourse and mating ends when the female regains control of her arms and separates the male,” the researchers point out.

In this video we can see how the male approaches while the female remains motionless:

Sexual Armament Carrera. The researchers comment that they did not directly measure the levels of neurotoxin, but it is a practice that “suggests an evolutionary armament career among the sexes, in which the cannibalism of large females is counteracted by males through the use of venom.” Fruit of this evolution is that the posterior salivary glands of the males, which is where the symbiotic bacteria that produce toxin accumulate, are three times larger than those of the females.

They also comment that they are not the only animals that accumulate that toxin in their bodies and that there are fish, mollusks or amphibians that produce it, so they will continue to investigate to identify whether other animals use it in order to reproduce and leave alive from the process. Ah, and something curious of the experiment: in one of the cases, one of the males bit at a point somewhat away from the aorta and the female took less time than the others to wake up: 35 minutes.

Speaking, people understand each other, but when hunger enters during intercourse, it is clear that there are species that fail to suppress those cannibal instincts. By the way, Wen-Sung Chung, one of the main researchers, has shared 15 GB of videos of the octopus copulating using these peculiar strategies.

Images and videos | Queensland University

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