What defines subsocial behavior in an adult insect?

• A. Living in the nest of another species.
• B. Caring for their own offspring without exhibiting other traits of eusociality.
• C. Cooperative brood care with multiple queens.
• D. Reproductive division of labor among nestmates.

Answer: (B)

Subsocial behavior centers on parental care: an adult insects protects, feeds, or provisions its own offspring, extending care beyond egg or early feeding, but without evolving a complex social system with nonreproductive helpers or distinct castes. This means the adult is directly investing in its brood, yet there’s no cooperative brood care by many adults, no multiple queens, and no division of labor among nestmates.

Caring for one’s own offspring fits this definition exactly, as it involves parent-offspring care without the broader social traits of eusociality. In contrast, living in the nest of another species isn’t about parental care of offspring and can involve social parasitism or simple shelter use. Cooperative brood care with multiple queens and reproductive division of labor are hallmarks of eusociality, not subsocial behavior.