Abstract Detail

Ecological factors that drive patterns of population genetic structure in plants

Satler, Jordan [1], Machado, Carlos [2], Herre, Allen [3], Heath, Tracy [4], Jander, Karin Charlotte [5], Eaton, Deren [6], Nason, John [7].

Modeling the process of codiversification in Panamanian figs and fig wasps and investigating the role shared wasps play in driving host genomic structure .

Mutualisms provide an opportunity for investigating the processes underlying long-term ecological associations and understanding how species interactions shape and structure evolutionary history in interacting lineages. The fig and pollinator wasp obligate mutualism is diverse (~750 described species), ecologically important, and ancient ~80–90 Ma, providing model systems for generating and testing hypotheses about the ecological and evolutionary processes that contributed to maintaining and promoting diversification in this long-term association. Once thought to be an example of strict codiversification, a growing body of research has overturned the dogma of a one-to-one fig-to-fig wasp species relationship, with evidence of host switching, cryptic speciation, and additional processes adding to the complexity of this association. Much of our understanding of the evolutionary processes underlying this interaction, however, has been inferred from limited data sets (i.e., few molecular markers) and cophylogenetic methods that do not explicitly model the underlying processes. These challenges motivate our work in using next-generation sequencing technologies and advancement in methodological approaches for investigating the fig and fig wasp mutualism. Here we utilize genome-wide sequence data to explore the process of codiversification in Panamanian strangler figs (Ficus subgenus Urostigma, section Americana) and associated fig wasp pollinators (Pegoscapus spp.). Gathering thousands of RAD (figs) and ultraconserved element (pollinator wasps) loci, we use a probabilistic approach to quantify the ecological and evolutionary processes generating cophylogenetic patterns in this system. Results suggest an important role for host shifting by the wasps in the history of this mutualism, providing a mechanism for potential introgression in the figs. We further explore demographic patterns for two fig species pairs that have both shared and unique pollinator species. These examples provide an opportunity to quantify the genetic consequence for host figs of being associated with a shared pollinator, as wasps arriving from a non-natal host species would produce F1 hybrids, providing a bridge for recurrent introgression. We test for introgression within two of these host species pairs, and ask how pollinator sharing influences fig genetic structure, reproductive isolation, and species boundaries. Overall, our work demonstrates the important role host shifting has played within the Panamanian strangler fig community, and how wasps shifting lineages through deep and shallow time has influenced the evolution of their host figs.

1 - Iowa State University, 251 Bessey Hall, Ames, Iowa, 50011, United States
2 - University of Maryland, Department of Biology, College Park , MD, 20742, USA
3 - Smithsonian Tropical Research Institute
4 - Iowa State University, EEOB, 251 Bessey Hall, Ames, Iowa, 50011, United States
5 - Uppsala University, Department of Ecology and Genetics, Uppsala, Sweden
6 - Columbia University, Department of Ecology, Evolution, and Environmental Biology, Schermerhorn Ext. Office 1007, 1200 Amsterdam Avenue, New York, NY, 10027, USA
7 - Iowa State University, Ecology, Evolution, And Organismal Biology, 251 Bessey Hall, Ames, IA, 50011, United States

Keywords:
cophylogenetics
codiversification
Host specificity
figs
fig wasps.

Presentation Type: Colloquium Presentations
Session: CO11, Ecological factors that drive patterns of population genetic structure in plants
Location: Tucson I/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 11:30 AM
Number: CO11014
Abstract ID:1037
Candidate for Awards:None