Which anatomical feature distinguishes soldier termites from other castes?

Soldier termites are distinguished from other castes primarily by their large mandibles. These powerful jaws are a critical adaptation for their role within the colony, as soldier termites are responsible for defending the nest against predators and potential threats. The enlarged mandibles allow them to bite and fend off intruders effectively, unlike workers or reproductive individuals that possess different adaptations more suited to their roles, such as foraging or reproduction.

While some other castes may exhibit variations in size or coloration, it is the large mandibles that serve as a specific anatomical characteristic directly linked to the soldier termites' defensive function, setting them apart from other castes. This unique trait enables soldiers to protect the colony, reflecting their specialized role and evolutionary adaptations within the social structure of termite societies.