Biologists have figured out how ants «invented» caste system

CC0 / the University of Texas «Insects Unlocked» program / AntBiologists have figured out how ants «invented» caste systemCC0 / the University of Texas «Insects Unlocked» program / Subscribe to the daily newsletter of the RIA Science

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. Ants, bees and other Hymenoptera insects «invented» the caste system because of lack of food and care for the offspring. About this scientist «told» specific changes in their genes, according to a paper published in the journal Science.

«We wanted to find out what causes the Queens to lay eggs and why the rest of their sisters become sterile workers. We found that switching between these roles are associated with ILP2 gene that controls the metabolism. If very little food, the species simply cannot afford to continue to race,» says Daniel Kronauer (Daniel Kronauer) from the University of Rockefeller in new York (USA).

Colonies of many species of social insects consist of several castes that perform different tasks. So, working individuals caring for offspring and feed the colony, the soldiers protecting her, and sexually Mature females and males participate in reproduction of the population.

The history of the emergence of this «caste system» has for many years been a matter of dispute among evolutionists. It’s not clear, what made the ancestors of ants and other hymenopteran insects to abandon reproduction and become willing slaves to one or a few «chosen» individuals.

Cronauer, and his colleagues have discovered how a similar social «stratification» among social arthropods, seeing how the genes were particularly active in the cells of the brain in workers and Queens of ants of the species Ooceraea biroi.

These insects are unusual in that their colonies no workers and Queens, and all their inhabitants can procreate, and to do it without the help of males. When they lay eggs, they «switch» on the part of the workers, taking care of their own and others ‘ larvae.

Trying to understand what causes them to do so, geneticists have studied what hormones and signaling molecules are present in the brain Ooceraea biroi during similar phases of their lives, and compared them with genes active in the neurons of the Queens and workers of other ant species.

As it turned out, all breeding ants were United by one factor – a high level of activity ILP2 gene responsible for assembling one of the versions of insulin. This site DNA, as the scientists explain, controls the rate of metabolism in the body of insects and, it seems, has many other functions in the body ants.

For example, the appearance of larvae in the ant colony significantly reduced the activity of this gene and made the insects more active in seeking food. In turn, the disappearance or the mass death of young animals, on the contrary, increased concentration of molecules ILP2 and translated ants in «multiply mode».

Further observation of the life Ooceraea biroi has shown that not all ants react to larvae in the same way. Some of them were greatly lowered insulin levels when young, and others, on the contrary, almost did not react to them and continued to lay eggs.

Scientists believe that such small differences were present among the ancestors of the ants, and their gradual strengthening led to the separation of the colonies into two groups the asexual workers and Queens. Similarly could occur caste and other social insects, including bees and termites.