Abstract Detail

Molecular Ecology and Evolution

Laport, Robert [1], Pilson, Diana [2].

Choosy natives and industrious immigrants: Genome duplication and pollinator discrimination in an ecologically dominant southwestern desert shrub (Larrea tridentata; Zygophyllaceae).

Understanding how one species becomes two is crucial to understanding patterns of biodiversity and the functioning of ecological systems. Polyploidy, the duplication of all chromosomes in an organism’s genome, is pervasive among angiosperms, implying it has a significant role in modulating botanical evolutionary trajectories and biodiversity. Plants with different chromosome complements often differ in traits associated with local adaptation, which can lead to population divergence and speciation. However, the degree to which such ecological divergence influences speciation remains unclear given the usually strong intrinsic reproductive isolation between plants with different chromosome numbers (“cytotypes”). We are employing an integrative approach to assess ecological differences and reproductive interactions in creosote bush (Larrea tridentata; Zygophyllaceae), an ecologically dominant southwestern desert shrub comprising recently formed (≤1mya) diploids, tetraploids, and hexaploids, to elucidate the significance of ecological differentiation in polyploid speciation. Using permanent, previously established areas of cytotype co-occurrance, as well as greenhouse experiments, we are addressing three questions: (1) What is the frequency of inter-cytotype pollen flow mediated by specialist and generalist pollinators? (2) Do sympatric cytotypes experience reproductive character displacement relative to allopatric cytotypes? and (3) Do sympatric cytotypes experience stronger pre-zygotic isolation than allopatric cytotypes, consistent with a pattern of reinforcement? Results from this study will help elucidate the evolutionary significance of polyploidy to ecological adaptation, incipient speciation, and patterns of biodiversity in many species, but will also contribute to understanding the ecology of an important plant species and its native pollinators in sensitive North American desert biomes.

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1 - University of Colorado-Boulder, Dept. of Ecology & Evolutionary Biology, Campus Box 334, Boulder, CO, 80309, USA
2 - University of Nebraska-Lincoln, School of Biological Sciences, Lincoln, NE, 68588, USA

Keywords:
polyploidy
native bees
speciation
plant-insect interactions
genetic structure.

Presentation Type: Oral Paper
Session: 40, Molecular Ecology and Evolution
Location: 102/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 10:30 AM
Number: 40009
Abstract ID:82
Candidate for Awards:None