What physical adaptation distinguishes bigheaded ant workers from minor workers?

The distinguishing physical adaptation between bigheaded ant workers and minor workers is the size of the head. Bigheaded ant workers are characterized by their significantly larger heads compared to minor workers. This adaptation serves a specific purpose in the colony's structure and function. The larger head allows bigheaded workers to perform special tasks such as defending the nest or handling larger prey, which is essential for the survival and efficiency of the colony.

Other physical traits, such as coloration or the length of antennae, may vary among different species or castes of ants but are not as definitive or characteristic in differentiating between bigheaded and minor workers. The number of legs remains constant across all ant workers and does not provide a distinguishing feature. Thus, the size of the head is key in identifying the specific roles and adaptations of these two types of ant workers.