Question

Cooperative brood care, overlapping of generation, parental care and division of labour is observed in

• A. Eusocial insects
• B. Semi social insects
• C. Quasi social insects
• D. Sub social insects

Hint:

Think of the prefix "Eu-" in "Eusocial" as meaning "true." "True" sociality requires the complete set of three criteria: cooperative care, overlapping generations, and caste division.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Sociality in insects ranges from solitary behavior to highly complex social structures.
E.O. Wilson and other sociobiologists established strict criteria to define and classify the different levels of social organization in animals.

Step 2: Detailed Explanation:
To be classified as "eusocial" (truly social), an insect species must exhibit three primary characteristics:
1. Cooperative brood care: Individuals within the colony work together to feed and care for offspring that are not their own.
2. Overlapping generations: Parents and offspring live together in the same nest, allowing adult offspring to assist in rearing younger siblings.
3. Division of labor: The colony is organized into reproductive castes (like queens and kings) and non-reproductive castes (like sterile workers and soldiers).
Let us compare this with lower social levels:
- Subsocial insects: Parents show simple parental care for their own eggs or nymphs, but do not share a common nest with cooperative care.
- Quasi-social insects: Members of the same generation share a nest and show cooperative brood care, but lack a division of labor (all females are fertile).
- Semisocial insects: Members share a nest and show both cooperative brood care and a division of labor, but lack overlapping generations.
Only eusocial insects possess all of these traits combined.
Common examples include honeybees, ants, termites, and yellowjacket wasps.

Step 3: Final Answer:
Eusocial insects exhibit all of these social characteristics.
Thus, the correct choice is (A).