Correlates of Variation in the Major/Minor Ratio of the Ant, Pheidole dentata (Hymenoptera: Formicidae)

Abstract

Major workers of the ant, Pheidole dentata, show a stronger alarm/defense response to members of the genus Solenopsis, including the fire ant, S. invicta, than to other kinds of ants. Nevertheless colonies stressed for 19 weeks (more than 3-fold the developmental time from egg to pupa) with S. invicta invaders failed to alter the rate of production of major workers. Production of queens and males begins when the colonies reach an adult worker population of 3,000 or more, and it is associated with a sharp reduction in major worker production. Colonies of P. dentata vary markedly among themselves in the adult major/minor ratio. The differences are restored after the ratio has been perturbed experimentally, and they are also restored after the colonies pass through episodes of queen and male production.