Octopuses torture and eat themselves after mating. Scientists finally figured out why

Many animal species die after reproducing. But octopuses have it even worse. After laying eggs, females

leave the brood, stop eating and beginhurt yourself. They can hit rocks, tear their skin, even eat their own flesh. This leads to death. By the time the young octopus crawls out of the egg, its mother is already dead. A few months later, the male also dies.

The short and dark life of octopuses long agointrigued scientists. In 1944, researchers hypothesized that mating somehow pressed a molecular “self-destruct” button inside the sea creatures.

It's taken nearly 80 years, but the idea is finally taking shape. Scientists recently found that mating appears to alter several important biochemical pathways in female octopuses.

Unusual behavior associated with changesin the metabolism of cholesterol in the optic glands. On its basis, more 7-dehydrocholesterol is formed, as well as some steroid hormones and bile acids. They influence the fact that females take more active care of the offspring, but at the same time force the octopus to harm itself.

During the study, scientists extracted visualglands of adult female octopuses and studied them. It turned out that they produce two main types of signaling molecules: neuropeptides and steroid hormones. The problem is that after mating, the activity of those genes that are responsible for encoding neuropeptides noticeably decreases. In turn, genes that encode enzymes involved in the synthesis of steroid hormones are expressed much more strongly. Cholesterol-7-desaturase is one of these enzymes. It converts cholesterol into 7-dehydrocholesterol, which controls maturation and lifespan in many invertebrates.

It is noteworthy that in humans there is a mutation that causesElevated levels of 7-dehydrocholesterol cause Smith-Lemli-Opitz syndrome. Let us remember that this is an autosomal recessive disease associated with metabolic disorders. The biochemical basis of this disease is a violation of cholesterol synthesis caused by insufficient activity or absence of the enzyme 7-dehydrocholesterol reductase. People with this mutation often injure themselves, and it is very similar to the behavior of the female octopus that has puzzled scientists.

After further research, scientistsfound that after mating, the metabolism of cholesterol and its components, for example, 7-dehydrocholesterol, changes dramatically in the visual glands of female octopuses. Most likely, its high levels are toxic in nature not only to humans, but also to octopuses. Perhaps they lead to the development of signaling factors that kill mollusks, triggering the regime

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