Eusocial is the highest degree of sociality in insects. To be eusocial, an insect species must demonstrate all 3 of the following characteristics:
- overlapping generations - Different generations are represented at any given time with the colony. Eggs, immatures, and adults live together.
- cooperative brood care - Members of the colony share responsibility for caring for the young.
- sterile worker caste - The colony is organized by a caste system, and workers are not reproductives.
Eusocial insects may also be called true social insects. All ants and termites are eusocial. Some bees, such as honey bees and bumblebees, are also eusocial, as are some wasps. Some aphids and thrips also meet the definition of eusocial.