SEX RATIO AND PARENTAL INVESTMENT IN AN ANT POPULATION

Parental investment, sexual selection and sex ratios.

Conventional sex roles imply caring females and competitive males. The evolution of sex role divergence is widely attributed to anisogamy initiating a self-reinforcing process. The initial asymmetry in pre-mating parental investment (eggs vs. sperm) is assumed to promote even greater divergence in post-mating parental investment (parental care). But do we really understand the process? Trivers ...

Sex ratio and parental investment in Trypoxylon (Trypargilum) agamemnon Richards (Hymenoptera, Crabronidae).

The life history and sex ratio data of the solitary wasp Trypoxylon agamemnon nesting in trap-nests in southern Brazil was recorded from January 2002 to December 2007. Its sex ratio is strongly female-biased, being bivoltine or multivoltine with until three generations per year. It has two alternative life histories (diapause and direct development) and overlapping generations. In addition to t...

Sex Ratio Compensation in Ant Populations.

Sex Allocation in the Ant Colobopsis Nipponicus (wheeler). I. Population Sex Ratio.

The relative power of queens and workers at controlling sex allocation in the ant Colobopsis nipponicus is investigated in this study. Results show that C. nipponicus completely satisfies Hamilton's assumptions concerning colony social structure: monogyny, monoandry, and no worker reproduction. A genetic survey of the population structure rejects possibilities of local mate competition, local r...

Parental Investment by Sex on Ifaluk

Trivers and Willard (Science 179:90-92, 1973) predict that where investment by parents in good condition increases the fitness of sons more than that of their sisters, while the opposite is true of parents in poor condition, parents with much to invest will favor sons, while those with little will favor daughters. Patterns of parent-child association on Ifaluk atoll are consistent with this pre...