Comparative phylogeography of codistributed aquatic insects in western North America: insights into dispersal and regional patterns of genetic structure

Abstract

1. Phylogeographic studies provide insights about complex systems at different evolutionary scales. In addition to providing evidence about ecological processes at the organismal level, a synthesis of studies across taxa can illuminate broad phylogeographic patterns at the landscape scale. 2. We compared the phylogeographic patterns of two codistributed species of aquatic insects, Pteronarcella badia (Plecoptera: Pteronarcyidae) and Drunella grandis (Ephemeroptera: Ephemerellidae), across much of their range in western North America. 3. We conducted population genetic analyses of P. badia and D. grandis individuals that co-occurred in 22 western North American localities. Patterns of genetic structure and gene flow were compared to test for differential dispersal ability and to determine whether broad-scale phylogeographic trends are consistent with patterns seen in terrestrial taxa across a similar geographic area. We also evaluated whether patterns observed in these species fit previously proposed models of genetic structure in aquatic organisms. 4. Pteronarcella badia showed greater genetic structure and lower rates of dispersal than D. grandis. Both taxa showed several shared geographic regions of genetic isolation, including the Bitterroot Valley in Montana, the Pacific Northwest, the southern Rocky Mountains and the Colorado Plateau. These broad-scale phylogeographic patterns are largely consistent with trends observed in several terrestrial taxa across the sample area. D. grandis showed patterns of gene flow consistent with an isolation-by-distance model of genetic structure. Patterns observed in P. badia reflect elements of multiple models and may highlight the value of the dendritic network approach to understanding genetic patterns of aquatic taxa at broad geographic scales.

Climate oscillations, glacial refugia, and dispersal ability: factors influencing the genetic structure of the least salmonfly, Pteronarcella badia (Plecoptera), in Western North America

“…We hypothesize that connectivity of the Widespread clade was interrupted during the most recent glacial periods, and certainly the LGM, as the Cordilleran Ice Sheet pushed P. badia into northern (Alaskan) refugia [ 27 , 28 ] and southern refugia. As the continental ice sheets retreated northward, our results show that post-glacial re-colonization expanded from refugial Montana localities [ 9 , 22 ] and not localities containing Widespread clade haplotypes that were previously connected with the Alaskan subclade, as evidenced by all haplotypes from the southern Canadian sample localities falling in the Northern Rockies clade.

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“…Studies that do exist are often limited in geographic scale [ 4 ]. Yet studies that have considered large geographic areas have provided powerful insights on the effect of historical climatic processes on genetic structure at the species and community level [ 5 – 9 ], as well as the importance of long-distance dispersal [ 10 ].…”

Influenced but not determined by historical events: genetic, demographic and morphological differentiation inHeleobia ascotanensisfrom the Chilean Altiplano

“…Ecological conditions and interactions, and environmental impositions (such as aridity) influence the genetic pool or structure in different taxa, but biological properties (e.g., dispersal capacities, life history traits, inter-specific interactions, etc.) may led to large differences in phylogeographic history (Zickovich & Bohonak, 2007; Murphy, Guzik & Wilmer, 2010; Sproul et al, 2014; Murphy et al, 2015). On the one hand, our study on H. ascotanensis compared to other taxa co-distributed in the Ascotán saltpan indicates that species show a deep genetic structure, but the times of divergence and the organization of population is slightly different (Morales, Vila & Poulin, 2011; Collado & Méndez, 2013; Cruz-Jofré et al, 2016).…”

Herbivore range expansion triggers adaptation in a subsequently-associated third trophic level species and shared microbial symbionts

“…Phylogeographic analysis can be used to explore the evolutionary history of a species 50–52 or to examine the temporal and spatial effects on co-evolutionary relationships of closely related species 53,54 . This type of study can help reveal the impacts of biological expansions on local communities over wide spatial scales.…”