What is "eusociality"

n. (context biology English) reproductive specialization, in which most individuals of a species are genetically infertile; the state of being eusocial.

Eusociality ( Greek eu: "good/real" + "social"), the highest level of organization of animal sociality, is defined by the following characteristics: cooperative brood care (including brood care of offspring from other individuals), overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. The division of labor creates specialized behavioral groups within an animal society which are sometimes called castes. Eusociality is distinguished from all other social systems because individuals of at least one caste usually lose the ability to perform at least one behavior characteristic of individuals in another caste.

Eusociality exists in certain insects, crustaceans and mammals. It is mostly observed and studied in the Hymenoptera ( ants, bees, and wasps) and in the termites. A colony has caste differences: queens and reproductive males take the roles of the sole reproducers, while soldiers and workers work together to create a living situation favorable for the brood. In addition to Hymenoptera and Isoptera, there are two known eusocial vertebrates among the rodents: the naked mole-rat and the Damaraland mole-rat. Some shrimps, such as Synalpheus regalis, are also eusocial. Edward O. Wilson has claimed that humans are eusocial, but his arguments have been refuted by a large number of evolutionary biologists, who note that humans do not have division of reproductive labor.

Several other levels of animal sociality have been distinguished. These include presocial (solitary but social), subsocial, and parasocial (including communal, quasisocial, and semisocial).