The role of post-pollination interactions in structuring co-flowering plant communities

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

Greater than 85% of all flowering plants and at least 30% of agricultural crops are pollinated by animals. In the wild plants exist in multispecies groups and often share pollinators which can lead to exchange of pollen between different species. This research will determine the mechanisms that allow different species of flowering plants to coexist when utilizing the same pollinators, that is, how they avoid or tolerate exchanging pollen. Thus, the work will advance understanding of the consequences of plant interactions via their shared pollinators and will provide data for predicting the composition and sustainability of natural flowering plant communities, as well as the consequences of disruption of these from global change, such as climate warming, invasive species, or pollinator decline. Identifying the traits that allow combinations of flowering plants to coexist will benefit society by informing agricultural practices for enhanced sustainability, and policies for conservation of biodiversity hotspots. The work will also provide training in pollination biology for elementary school students and high school teachers via workshops and hands-on activities that are designed and implemented by graduate students and postdocs. The question of how plant-pollinator interactions contribute to flowering plant communities has largely focused on plant traits that mediate pre-pollination interactions, and ignored the potential for traits that mediate post-pollination processes. This work will test the novel assertion that plant traits (e.g., style and stigma features) which influence the female fitness costs of pollinator sharing (detrimental effects of heterospecific pollen receipt) play an important, yet underappreciated, role in mediating coexistence of flowering plants within communities. Using replicated California wildflower communities as a model, the work will link plant traits with the pattern and costs of heterospecific pollen receipt, and modifiers of pre-pollination interactions at a community-wide scale. In doing so, the work will test the idea that within a co-flowering community tolerance and avoidance of heterospecific pollen receipt are alternate strategies for coexistence, and that tolerance is a stabilizing force that depresses the risks of reproductive failure of species that receive high heterospecifc pollen. Thus, the work will accelerate our understanding of the primary ways pollinators contribute to the coexistence flowering plants, an area urgently in need of greater study, especially in the face of global changes affecting both plants and pollinators.