| This study investigated patterns of reproductive resource allocation between female and male function and within female function for 17 temperate orchid species. Resource allocation between the competing sex roles and within a sex function was considered. I investigated opportunities for adjustment of maternal resource investment during one reproductive season. Because orchid ovules are immature at anthesis and further development is triggered by pollination, orchids may demonstrate unique opportunities for adjustment of ovule number to pollen receipt. However, like other angiosperms orchids did not adjust ovule number to pollen load. Instead, seed number, but not size, responded to pollen quality. I also considered the relation between resource allocation, P:O ratio and pollination efficiency. Compared to species with granular pollen, a very high proportion (10--40%) of pollen removed from orchid flowers reaches stigmas (pollination efficiency). Correspondingly, orchids have considerably lower P:O than angiosperms with granular pollen. Within orchids and among angiosperms P:O ratio varies negatively with pollination efficiency. These results are discussed in light of the effects of increased pollination efficiency on local mate competition and resource allocation. |
