XVI International Botanical Congess

A comprehensive review of life-history differences between the sexes of dioecious species will be presented. The hypothesis that sex-differential costs of reproduction are significant evolutionary determinants of sexual dimorphism in life histories is supported by comparative data on investment in reproduction and life-history traits. There is a pattern of a higher cost of reproduction for the sex investing relatively more in reproduction, but it is not universal. Factors ameliorating between-sex differences in the cost of reproduction include the timing of investment in reproduction, the frequency of reproduction, physiology, and sex-differential herbivory. In addition, sexual selection may have led to sexual dimorphism that causes higher costs of reproduction for males, in spite of their lower biomass allocation to reproductive tissues.