Variation in pollinators' behavior will influence how pollen is transferred and subsequently impact rates of inbreeding, paternity, and migrations between populations. As these processes play a large role in determining the genetic makeup of the next generation, they can influence the evolutionary trajectory of a population. Behavioral traits such as foraging pattern will determine how frequently pollen is transferred between flowers on the same plant, and between neighboring plants, which will determine the rate of inbreeding, while grooming and preferred floral resources, will determine if pollen from multiple flowers is likely to accumulate, increasing the chance of pollen carryover and multiple paternity. And finally, foraging distances will determine the frequency that a visitor travels between populations. In combination, these factors can have an important impact on the distribution of genetic diversity within a species. We compared, pollinator visitation, paternity, inbreeding and fitness of two species of Clarkia with contrasting pollinators. In this system, we tested the following hypotheses. 1) Inbreeding levels will be higher in plant populations visited by more efficient pollinators, such as bees or bumblebees. 2) The number of paternal donors will be higher in plant populations visited by nectar collecting species than pollen collecting species, and 3) Population differentiation will be lowest in populations visited by insects that forage over larger areas.
Results/Conclusions
Clarkia breweri populations were predominately visited by lepidopteran insects (Hyles (61%), Noctuid moths (25%) and Butterflies (7%)), while C. concinna populations were visited by Bumblebees (16%) and Bombyliid flies (57%). Visitation varied by population. On average the rates of inbreeding within-population were lower (Fis=0.10 vs Fis=01.6) and the number of paternal donors was higher in the Lepidopteran pollinated populations compared to the Hymenopteran pollinated populations, supporting our first two hypotheses. By contrast, we found no support for our third hypothesis, with no significant difference in population differentiation based on the primary visiting insect.