The latter generally have much larger heads and mandibles in comparison to their usually fairly modest body size.

[citation needed] The distinctive major workers have earned the genus Pheidole the nickname of "big-headed ants".

The major workers of a Pheidole colony, while they may look fierce, are often quite shy and are often the first to flee on any hint of danger.

Many Pheidole species are the prey of parasitoid phorid flies that lay their eggs on the major workers; the fly larvae grow mainly in the head capsules of the victims, eventually decapitating them, and probably would starve in the bodies of minor workers.

[citation needed] In most cases, the major workers are employed within the nest to break up large food items, or outside to carry large items, such as seeds; many Pheidole species are ecologically important seed consumers ("harvesters").