Self-pollination and its costs in a monoecious fig (Ficus aurea, Moraceae)in a highly seasonal subtropical environment

The unusual Rural phenology of most monoecious figs, related to their highl y specialized pollination mutualism with agaonid wasps, combines pronounced dichogamy at the level of inflorescences and individuals with population-l evel asynchrony in flowering. This floral phenology ensures that outcrossin g strongly predominates. Fig populations map thus be expected to possess de leterious recessive alleles that lead to inbreeding depression when selfing does occur. However, whether monoecious figs are self-compatible and wheth er selfing results in inbreeding depression have never been investigated. U sing wasps as "pollination tools" and exploiting infrequent overlap in male and female phases on the same tree, we conducted controlled selfed and out crossed pollination experiments in Ficus aurea. Our results show that this species is totally self-compatible, No negative effects of selfing could be demonstrated on syconium retention, number of vacant ovaries, seed set, or seed germination. However wasp production had a tendency to be higher afte r self-pollination. While it is possible that inbreeding depression is expr essed at later developmental stages, its absence at the early stages we exa mined is nonetheless surprising for a plant expected to be highly outcrosse d. It is likely that selection pressures other than avoidance of inbreeding are responsible for the evolution and maintenance of the unusual floral ph enology of figs.