Abstract Detail



Ecology

Cullen, Nevin [1], Xia, Jing [2], Wei, Na [3], Kaczorowski, Rainee [4], Arceo-Gomez, Gerardo [5], O'Neill, Elizabeth [6], Hayes, Rebecca [6], Ashman, Tia-Lynn [6].

Pollinator traits are a better predictors of insect-carried pollen load attributes than the local floral resources.

Insect pollinators play a crucial role in reproduction for the majority of flowering plants by transferring pollen between conspecifics. However, plants often receive pollen of heterospecifics, which can reduce the recipient’s seed production. While mixed pollen loads on stigmas are common, we lack a sufficient understanding of how these are generated. Are pollinators carrying multiple species of pollen and/or do pollinator taxa vary in their load diversity? Here we compared the relative effects of pollinator traits and locally available floral resources in shaping pollen loads on the bodies of bee and fly pollinators. We collected 346 insects from a diverse serpentine seep habitat in Northern California and characterized the amount, composition and diversity of pollen on their bodies. We surveyed the flowering plant community and ~1800 plant-pollinator interactions to quantify degree of specialization for each insect species. We used a model selection approach to test three hypotheses concerning the factors structuring pollen load attributes: 1) pollinator traits (sex, taxonomic order, body size and degree of specialization), 2) available floral community diversity, or 3) the interaction between pollinator traits and floral community. Pollen load diversity was modeled with generalized least squares and corrected for phylogenetic relatedness of pollinator taxa, while pollen load composition was modeled with redundancy analysis. Pollinator traits more strongly influenced pollen load size, diversity and composition than the diversity of locally flowering plants. Specifically, pollen load diversity increased with pollinator size and decreased with degree of pollinator ecological specialization. Pollen loads ranged from a single species to 16 different species on a single pollinator. Male bee pollen loads were smaller, but more diverse than female bees (84% more diverse), while they were equivalent in size but more diverse than flies (28% more diverse). Additionally, traits drove pollinators to acquire pollen loads of different taxonomic and phylogenetic composition. Finally, plant taxonomic and phylogenetic composition of pollen loads only weakly reflected the composition of open flowers where pollinators were foraging. Together, our results suggest that functional characteristics of pollinators determine how many and which pollen species they transport, and that pollen loads are not constrained by the breadth of available floral resources. Thus, factors that affect pollinator species pool composition may play an important role in heterospecific pollen transfer among plants, which can be verified by comparing composition of pollen on pollinators and stigmatic pollen loads of the plants they visit.


1 - Dept. Of Biology & Environment, University Of Haifa-Oranim, Tivon, 36006, Israel
2 - South-Central University for Nationalities, College of Life Sciences, 182 Minyuan Road, Hongshan District, Wuhan, Hubei, 430074, China
3 - Holden Arboretum, 9550 Sperry Rd, Kirtland, OH, 44094, USA
4 - 9809 W. Pleasant Valley Rd, Parma, OH, 44130, United States
5 - East Tennessee State University, Biological Sciences , PO Box 70703, Johnson City, TN, 37614, United States
6 - University of Pittsburgh, Biological Sciences, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA

Keywords:
pollinators
serpentine
foraging behavior
heterospecific pollen transfer
networks.

Presentation Type: Oral Paper
Number: ECO6001
Abstract ID:758
Candidate for Awards:None


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