Amelia Scheiber, “Variation in Reproductive Success Across the Flowering Season”
Mentor: Jeffrey Karron, Biological Sciences
Poster #179

Seed production of flowering plants is frequently limited by the quantity of pollen deposited by pollinators onto receptive stigmas.  This pollen limitation of reproductive success can be experimentally tested by supplementing plants with pollen, and if those plants produce more seeds when pollen supplemented, then it can generally be concluded that reproductive success is limited by pollen receipt. Primula meadia (shooting star) utilizes a form of pollination known as buzz pollination. In order for the pollen to be released, bees must grasp onto the anther cone and petals, and move their flight muscles rapidly. This vibration of the anthers causes the pollen to emerge explosively through openings at the tips of the anthers, as well as through slits on the sides of the anthers. Primula meadia does not have any nectar, however, and in spring, newly emerging bumble bee queens are primarily foraging for nectar, which potentially limits pollination services to this buzz-pollinated species. In previous studies involving Primula meadia, seed production was greatly increased with pollen supplementation, indicating that Primula meadia is severely pollen limited. In the current study, I am exploring whether the magnitude of pollen limitation varies over the flowering season.  I am looking at the number of seeds produced from individual flowers, collected from three different time periods across the flowering season. Each of these populations had a control group, where pollen was not supplemented, and a group that was manually supplemented with pollen.  I hypothesize that pollen limitation will be highest early in the season when few bumble bees are foraging for pollen.