Concept: Social insects - Social insect, any of numerous species of insects that live in colonies and manifest three characteristics: Group integration Division of labour Overlap of generations. Social insects are best exemplified by all termites (Isoptera; sometimes Blattodea) and ants (Formicidae) and by various bees and wasps (Hymenoptera). Social insects are differentiated in structure, function, and behaviour into castes, the major ones being the reproductives (e.g., the queen) and the steriles(workers and soldiers). Besides carrying out the basic function of reproduction, the members of the reproductive caste generally select the site for a new colony and excavate thefirst galleries. The workers care for the eggs and larvae, collect food for other members of the colony, and construct and repair the nest, while the soldiersdefend the colony against predators. They establish fungus gardens and feed on them. Explanation: Assertion (A): Termites and ants are social insects. This correct statement. Reason (R): Both establish fungus garden in their nests to feed on fungus. This is also a correct statement but the reason for being a social insect is not because they feed on fungus and build nest garden. But because they live in colonies and divide their work Hence, Both A and R are true but R is not the correct explanation of A.