Frank, S. A. 1995. Sex allocation in solitary bees and wasps. American Naturalist 146:316-323.

Fisher's (1958) famous sex ratio theory suggests that natural selection favors equal investment in each sex. Because of Fisher's theory, authors typically assume that biased population allocation requires spatial subdivision, such as local mate competition, or unusual genetics, such as cytoplasmic inheritance. However, I have shown previously that a biased population-level sex allocation occurs if individuals adjust the sex ratio of their offspring in response to resource availability or environmental cues (Frank 1987, 1990).

Recently, Boomsma (1989) and Helms (1994) have found a positive relationship between female:male (F/M) size ratios and F/M population allocation ratios in some Hymenopteran groups. In this paper I apply the theory I developed previously to explain the association between size and allocation ratios.