What if workers in social hymenoptera were males?

Abstract

In social wasps, bees and ants, the worker caste is always female. Utilizing the approach of Trivers & Hare (1976) , the sex-ratio of investment in reproductives which is preferred by different types of colony members is calculated, under the imaginary circumstance that female and male workers are equally possible. The preferred ratio of a male worker is identical to that of his mother. A queen or female worker who can lay male-worker eggs therefore gains allies in her struggle to bias the investment ratio in her favor. This can have various social consequences, depending on whether the queen or female workers lays the male eggs, and on whether female workers are the queen's daughters or sisters. The principal prediction of this imaginary situation is that if males can be just as good workers as females, the queen should prefer that all workers be male. Yet this never happens, even when the queen controls the sex of all colony offspring. This supports the view that it is an inability to be good workers which excludes hymenopteran males from the worker caste.