Ecological and Evolutionary Characteristics of New England's Buzz Pollinated Flora

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Pollination syndromes, floral characteristics, vibratile dehiscence, angiosperms, buzz pollinated species
Curran, Bridget
Pollination syndromes are sets of floral characteristics that have evolved to attract specific pollinator groups for successful reproduction. Buzz pollination is a specialized form of vibratile dehiscence whereby a pollinator must produce a vibration to expel pollen from the anther. This is thought to occur in approximately 6% of angiosperms as an evolutionary adaptation to economize pollen, and we now know it occurs in approximately 3% of New England species. Unlike other pollination syndromes (e.g., moth, hummingbird, etc.) buzz pollinated species possess a relatively broad range of perianth morphologies. Buzz pollination has been studied in tropical and laboratory settings, but community-level studies are few and the breadth of morphological and ecological variation in New England is poorly understood. With my research, I tested the hypothesis that buzz pollinated species have a broad geographic distribution across New England habitats (as opposed to being restricted to one of a few special habitats) and that differences in phenology serve to reduce competition for pollinators. Second, I tested whether there are groups of plant species with similar floral morphologies associated with specific foraging behavior. We used online databases, published literature, and herbarium specimens to determine the number of buzz pollinated species in New England. Spatial analyses of georeferenced herbarium records were used to construct a species distribution model and annotated iNaturalist observations were summarized to determine species’ phenologies. We used linear regression, multiple factor analysis, and analysis of variance to better understand the relationships between anther morphology and several other floral and environmental characteristics. Additionally, we recorded buzz pollination frequency, amplitude, and duration for a small subset of plant species in the field to determine whether buzzing characteristics were associated with specific floral forms. We find that 89 species of buzz pollinated plants occur throughout almost every habitat in New England (though primarily in anthropogenic habitats), that divergence in flowering times occurs in some (not all) habitats, and that peak flowering time for buzz pollinated species occurs during the months of June and July. We find a close relationship between anther length and specific perianth morphologies, and a negative correlation between pore diameter and anther length. We also find significant differences in buzzing characteristics among several species. Because buzz pollinated plant species occur in a wide variety of habitats and range from common to rare, basic knowledge on how bees are interacting with these species in New England will foster a greater understanding of community interactions and consequences of disturbances like habitat fragmentation and type conversion. Future research on plant phenology and how differences in flowering times relate to the selective pressures acting on plant-pollinator resources will provide insight on the evolutionary trajectory of this syndrome.