Abstract Detail



Species delimitation in polyploid complexes

Laport, Robert [1].

The biodiversity consequences of whole genome duplication: polyploidy shapes pollinator-mediated assortative mating and herbivore diversity.

Elucidating how one species becomes two is crucial to understanding patterns of biodiversity. Polyploidy—whole genome duplication—is an exceedingly common genomic mutation shaping vascular plant biodiversity. Recent efforts to characterize how the phenotypic and genomic novelty of polyploids alters interspecific interactions support considering polyploids as discrete units of biodiversity in many evolutionary and ecological contexts. Yet, the cascading evolutionary and ecological effects of such changes remain unclear, relegating species comprising ploidal variation to a taxonomic no-man’s land where polyploidy is simultaneously considered a major mechanism of novelty and speciation, but insufficient for species recognition. Employing integrative studies in the North American creosote bush (Larrea tridentata; Zygophyllaceae), an ecologically dominant desert shrub comprising recently formed (≤1mya) diploids, autotetraploids, and autohexaploids that host an extraordinarily diverse assemblage of insect pollinators and herbivores, we assess the biodiversity implications of genome duplication for 1) generalist and specialist pollinator foraging patterns and their consequences for inter-cytotype reproductive isolation, and 2) how plant-herbivore interactions are shaped by polyploidy. We find that the cytotypes of L. tridentata act as independent units of biodiversity with whole genome duplication having profound and multifaceted effects on interspecific interactions. Sympatric L. tridentata cytotypes are visited by similar bee assemblages, but biases in pollen collection contribute to appreciable assortative mating and inter-cytotype reproductive isolation. The distributions of diploid, and polyploid L. tridentata also structure specialist galling insect distributions and may have influenced their recent radiation, with several closely-related species galling their preferred host cytotype even when the cytotypes occur sympatrically. The results of our integrative studies suggest different ploidies may often represent novel species with unique plant-animal interactions that should be more widely recognized to acknowledge the contemporary importance of genome duplication to evolutionary trajectories and global patterns of biodiversity.


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1 - Rhodes College, Department Of Biology, 2000 North Parkway, Memphis, TN, 38112, United States

Keywords:
polyploidy
speciation
assortative mating
biodiversity
plant-animal interactions.

Presentation Type: Colloquium Presentations
Number: 0002
Abstract ID:167
Candidate for Awards:None


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