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(biology) Of or pertaining to certain social animals' societies (such as those of ants) in which sterile individuals work for reproductive individuals whose genetic endowment they share.

Co-operative brood rearing, seen here in honeybees, is a condition of eusociality.

(biology) Of or pertaining to certain social animals' societies (such as those of ants) in which sterile individuals work for reproductive individuals whose genetic endowment they share.

Suzanne Batra introduced the term "eusocial" after studying nesting in Halictid bees including Halictus latisignatus, pictured.

(biology) Of or pertaining to certain social animals' societies (such as those of ants) in which sterile individuals work for reproductive individuals whose genetic endowment they share.

Weaver ants, here collaborating to pull nest leaves together, can be considered eusocial, as they have a permanent division of labor.