Geographic isolation due to patchy or fragmented habitat may be mitigated differentially in plant species depending on their primary pollinators. The level of inbreeding a plant might have experienced in the past will depend on size of population, number of founders, mating system, and distance to nearest neighboring populations. We have collected seed from two species, Oenothera gayleana (bee-pollinated) and O. hartwegii subsp. filifolia (hawkmoth-pollinated) which co-occur on gypsum deposits in the overlapping portion of their ranges. These populations have similar population sizes and are equally isolated, hence we are interested in the role pollinators might have played in determining the degree of isolation and therefore inbreeding in past. We found no evidence in either species for population genetic structure at the local scale, despite a distance of up to 13km between populations, but at a regional scale (60-440km), the bee pollinated species showed higher degrees of isolation. These results suggest that pollinators may be better at connecting populations across the landscape at a larger scale than estimated pollinator foraging distance would predict. We have conducted a number of crosses which hope to compare the effects of inbreeding (crossing among siblings) and outcrossing (crosses between distant populations) in these two species which show very different genetic structure due to having very distinct pollinators. 

The student will be in charge of conducting germination experiments to determine if there are any differences in reproductive fitness. Then they will grow up plants to determine if there are any fitness differences between treatments, including plant size, biomass, morphological changes, scent and seed set. This study is part of a larger project, hence students will also be helping with other task associated with project.