ufla.edu | Insects exhibit several levels of social organization. Many species
live in groups for some portion of their lives, but not all of these
groups are truly social. For instance, chimney bees,
Anthophora abrupta,
do live in groups for periods of time, but they are nevertheless
solitary bees. Female chimney bees build nests in large aggregations,
giving the impression that they are social, but in fact each female
builds and provisions her own nest. In contrast, some insects, ants,
for instance, live in complex societies called colonies and depend on
continual social interactions to survive. Members of these social
species cannot survive as individuals; they must live as a part of a
colony.
Three characteristics define the levels of sociality observed in insects. These characteristics are: 1) reproductive division of labor:
most individuals are non-reproductive and specialize in colony growth,
maintenance, and defense while only a few reproduce; 2) cooperative brood care: individuals within the colony care for offspring that are not their own; and 3) overlapping generations:
offspring contribute to colony labor while their parent(s) (at least
their mothers) are still alive and inside the colony. Species that
express all three of the above characteristic are highly social or eusocial. The most common eusocial insects are bees, wasps, ants, and termites (Table 1).
Honey bees (Hymeoptera: Apidae: Apis) meet all three of the criteria described above and are therefore eusocial:
- Reproductive division of labor—Each honey bee colony consists of a queen (reproductive female), workers (non-reproductive females), and drones (males). Each caste has a clearly defined role that is not performed by any other caste.
- Cooperative brood care—Workers care for the queen’s offspring. In most cases the queen’s offspring are sisters to the workers who are rearing them.
- Overlapping generations—Honey bee queens can live several years and coexist in the colony with their offspring (workers and drones).
