abstract
| - 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 labour 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 possibly mammals. It is mostly observed and studied in Hymenoptera, which include ants, honey, bumble, and stingless bees, and yellowjacket and hornet wasps (the Vespidae) and termites. For example, a colony has caste differences; queens and reproductive males take the roles as the sole reproducers while the 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 from the order Rodentia, which includes the naked mole-rat and the Damaraland mole-rat. Most of the individuals cooperatively care for the brood of a single reproductive female (the queen) to which they are most likely related. There are also a number of shrimp, including Synalpheus regalis who display eusociality. Several other levels of animal sociality have been distinguished. These include presocial (solitary but social), subsocial, and parasocial (including communal, quasisocial, and semisocial).
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