The role of pollination level on the reproduction of females and hermaphrodites in the gynodioecious plant Gypsophila repens (Caryophyllaceae)

In gynodioecious plant species, females are expected to have more resources available for maturing seeds because pistillate flowers are smaller, do not produce pollen, and are thus less costly that perfect flowers. The potential female advantage arising from more abundant resources is, however, likely to vary depending on whether seed production is limited by resource or pollen availability. Here we experimentally investigated the influence of pollen and resource limitation on female advantage in a gynodioecious species using two levels of pollination. Total seed production of females was always greater than that of hermaphrodites: females produced more flowers and more fruits that contained similar numbers of seeds of similar mass. Under low pollination, female and hermaphrodite plants allocated resources to increased flower production rather than to increased seed size or quality. We did not detect any influence of pollen or resource limitation on female advantage, which remained similar under low (= abundant resources) and full pollination. Outcrossed fruits performed better than selfed fruits when the same plant received both selfed and outcrossed pollen on different flowers. These differences were not greater under high pollination, possibly because resources available for each fruit did not differ between our pollen intensity treatments.