Strange way of storing 'seed' in female animals

Scientists have found that, in some animals in nature, females have managed to store male sperm during a long time, even up to several years before fertilizing an egg, although there are always around. potential mates.

The case is difficult to explain in guppies

A new study finds that a quarter of male male guppies in Trinidad and Tobago were born from sperm of dead fathers. Some sperm are even stored for up to 2 generations.

According to the researchers, after mating, the female guppies store "seedlings " in a specialized chamber in the ovary, feeding them with a small amount of sugar until fertilizing the eggs. This strange behavior stems from the fact that females usually live at least 1 year longer than males. Therefore, sperm storage from various partners gives children the ability to choose the best genes for future offspring.

Since the pups do not have any care for the descendants even when they are alive (probably because of that, the mother fish does not take care of the baby after birth), so the death does not prevent them from becoming a father. , according to research published in the journal Proceedings of the Royal Society B.

However, researchers at the École Normale Supérieure (France) do not know whether the sperm quality of guppies is destroyed over time, although the " reserve " can clearly be fertilized. some eggs. In addition, they have yet to explain why the females who continue to store the male sperm have died despite many potential mates around them, capable of providing fresher semen.

The phenomenon is not rare

Eastern bell rattles also store sperm.(Photo: NatGeo)

Sperm storage does not seem to be a rare phenomenon in the natural world. Many other animals are also found to have this behavior, including domestic chickens. In 2011, researchers from the University of North Carolina and the University of Georgia discovered that the Eastern ring-tailed snake, the scientific name Crotalus adamanteus, had stored sperm for an unusually long time.

The conclusion was drawn when a wild rattlesnake snatched in Florida in 2005 suddenly gave birth in 2010 despite being kept away from other snakes. Initially, the scientists assumed that this was an example of a "virgin child" phenomenon , a form of asexual reproduction, in which females provide both sets of chromosomes to their descendants. But gene analysis revealed, this is the product of a pair of parent snakes.

The question is: How do children force sperm to perform their function at a certain time? Through the study of the popular, scientifically recognized octopus vulgaris, biologist Anna DiCosmo from Napoli Federico II University (Italy) and colleagues tested the hypothesis that the children were secretes chemical attractants.

Males of many animals can sense and find these chemicals. DiCosmo's group found that, when the offspring of other species involved in the release of eggs into octopus, the males would be attracted to the chemicals in the eggs. Males will swim chemically and "drop" sperm.

Although the octopus fertilizes eggs inside, DiCosmo doubts whether this species uses scientific attractants to awaken sperm from hibernation. The study eventually revealed that the Octo-SAP protein in octopus eggs triggered the swimming state of the sperm and the "breeds" swam to a higher concentration of Octo-SAP.

Sperm stocking octopus may be due to less chance of regular mating.

DiCosmo has made some assumptions about sperm storage behavior in octopus. This may be due to an asymmetry of time for a female egg to reach maturity with rapid sperm production in males. For example, females may not have mature eggs ready to mate with males, an activity that does not seem to happen regularly.

"Because octopus is a lonely animal, they don't have many opportunities to meet their partners. For this reason, sperm storage is one of the most effective strategies to maintain the breed. Immediately fertilize it. or external fertilization can lead to failure, " said DiCosmo.