Fig. 4.

A summary of the hypothesized relationship between JH, ecdysteroids, age and division of labor in P. californicus workers. Age is defined as the age of any given worker cohort, from adult emergence until death. That is, as a group of workers age (x-axis), the proportion of workers performing different tasks changes (y-axis). High JH content corresponds to foraging activities, and a high ecdysteroid content with nest tasks; the bisecting line represents the proportion of workers performing nurse (blue) or foraging (yellow) tasks, and demarks the different hormone levels. (A) In age-typical colonies, the vast majority of young workers have low JH levels and high ecdysteroid levels, and are inside the nest performing nursing tasks. As they age, more workers initiate foraging, which is a behavioral transition that is associated with high JH and low ecdysteroids. (B) In single-cohort colonies, foraging onset begins at a much earlier age, and proceeds faster, until the colony has achieved the necessary balance between nurses and foragers. In both colony types, the onset of foraging coincides with increased JH and decreased ecdysteroid levels.