Abstract Detail


Morley, Lydia [1], Spalink, Daniel [1].

“Overgeneralizing pollinator generalists: native North American orchids and their diverse pollinator dynamics”.

Orchids and their pollinators constitute some of the most studied co-evolutionary relationships. Indeed, plant-pollinator interactions, and their various evolutionary consequences, appear to be well understood. However, much of the work surrounding plant-pollinator relationships has focused on highly specialized associations, such as speciation caused by the evolution of novel morphological characteristics. Many authors have also discovered that on a global scale, pollinator specialization is associated with increased rates of diversification, while generalism is not. However, this focus on specialization has largely ignored the interesting and important phenomena guiding the history, biogeography, and ecology of more generalized relationships. By integrating phylogenies of orchids and their known pollinators, occurrence records, and climatic data, we aim to show that less specific systems are not a monolith: Not only does generalism come in degrees, but it is also labile across the ranges of individual species. We have explored three central lines of inquiry: 1) We have measured patterns of pollinator turnover across orchid ranges and analyzed its relationship to general pollinator diversity. 2) We have examined the relationships between pollinator assemblage and occupancy of geographic and ecological space. 3) We explored the evolution of different pollinator strategies across the native North American orchid phylogeny, namely pollinator diversity, conservatism of pollinator relationships, and the evolution of self-pollination. In effect, pollinator generalist systems contribute to diverse and unique orchid ecologies, range dynamics, and evolutionary histories. Such variability impacts the way we think about both orchid conservation and evolutionary potential. Across the native North American phylogeny, self-pollination has appeared multiple times, and pollinator assemblages appear to vary through time. Further, while we don’t expect to find that orchids with more diverse pollinators necessarily always occupy larger ranges, we do expect to find greater degrees of spatial turnover in pollinator assemblage, and less pollinator limitation. This would, in effect, allow more generalized orchids to occupy greater areas of their fundamental niche compared to their specialized relatives. Importantly, we don’t have complete pollinator data for any orchid. Our study has shown that pollinator relationships change (sometimes drastically) across an orchid’s range, and so a single pollinator observation at a single location doesn’t provide sufficient information. Our hope is that this study serves as the impetus for newfound enthusiasm in broad reaching efforts to observe and identify native north American orchid pollinators. We also hope that this work will be the foundation for a new perspective on pollinator-driven divergence.

1 - Texas A&M University, Ecology and Conservation Biology, 534 John kimrough BLVD, 2258 TAMU, College Station, TX, 77843, United States

none specified

Presentation Type: Oral Paper
Number: BIOG III010
Abstract ID:633
Candidate for Awards:None

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