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1. Species‐level view of population structure and gene flow for a critically endangered primate ( Varecia variegata )

   https://doi.org/10.1002/ece3.1119  

   Baden, Andrea L. ; Holmes, Sheila M. ; Johnson, Steig E. ; Engberg, Shannon E. ; Louis, Jr, Edward E. ; Bradley, Brenda J. ( June 2014 , Ecology and Evolution)

   Lemurs are among the world's most threatened mammals. The critically endangered black‐and‐white ruffed lemur (Varecia variegata), in particular, has recently experienced rapid population declines due to habitat loss, ecological sensitivities to habitat degradation, and extensive human hunting pressure. Despite this, a recent study indicates that ruffed lemurs retain among the highest levels of genetic diversity for primates. Identifying how this diversity is apportioned and whether gene flow is maintained among remnant populations will help to diagnose and target conservation priorities. We sampled 209 individuals from 19 sites throughout the remainingV. variegatarange. We used 10 polymorphic microsatellite loci and ~550 bp of mtDNAsequence data to evaluate genetic structure and population dynamics, including dispersal patterns and recent population declines. Bayesian cluster analyses identified two distinct genetic clusters, which optimally partitioned data into populations occurring on either side of theMangoro River. Localities north of the Mangoro were characterized by greater genetic diversity, greater gene flow (lower genetic differentiation) and higher mtDNAhaplotype and nucleotide diversity than those in the south. Despite this, genetic differentiation across all sites was high, as indicated by high averageF_ST(0.247) and Φ_ST(0.544), and followed a pattern of isolation‐by‐distance. We use these results to suggest future conservation strategies that include an effort to maintain genetic diversity in the north and restore connectivity in the south. We also note the discordance between patterns of genetic differentiation and current subspecies taxonomy, and encourage a re‐evaluation of conservation management units moving forward.

    

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2. Population genomics of divergence among extreme and intermediate color forms in a polymorphic insect

   https://doi.org/10.1002/ece3.1928  

   Lozier, Jeffrey D. ; Jackson, Jason M. ; Dillon, Michael E. ; Strange, James P. ( January 2016 , Ecology and Evolution)

   Geographic variation in insect coloration is among the most intriguing examples of rapid phenotypic evolution and provides opportunities to study mechanisms of phenotypic change and diversification in closely related lineages. The bumble beeBombus bifariuscomprises two geographically disparate color groups characterized by red‐banded and black‐banded abdominal pigmentation, but with a range of spatially and phenotypically intermediate populations across western North America. Microsatellite analyses have revealed thatB. bifariusin the USA are structured into two major groups concordant with geography and color pattern, but also suggest ongoing gene flow among regional populations. In this study, we better resolve the relationships among major color groups to better understand evolutionary mechanisms promoting and maintaining such polymorphism. We analyze >90,000 and >25,000 single‐nucleotide polymorphisms derived from transcriptome (RNAseq) and double digest restriction site associatedDNAsequencing (ddRAD), respectively, in representative samples from spatial and color pattern extremes inB. bifariusas well as phenotypic and geographic intermediates. Both ddRADandRNAseq data illustrate substantial genome‐wide differentiation of the red‐banded (eastern) color form from both black‐banded (western) and intermediate (central) phenotypes and negligible differentiation among the latter populations, with no obvious admixture among bees from the two major lineages. Results thus indicate much stronger background differentiation amongB. bifariuslineages than expected, highlighting potential challenges for revealing loci underlying color polymorphism from population genetic data alone. These findings will have significance for resolving taxonomic confusion in this species and in future efforts to investigate color‐pattern evolution inB. bifariusand other polymorphic bumble bee species.

    

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3. Population connectivity across east Australia's bioregions and larval duration of the range‐extending sea star Meridiastra calcar

   https://doi.org/10.1002/aqc.3973  

   Klanten, O. Selma ; Gall, Mailie ; Barbosa, Sergio S. ; Hart, Michael W. ; Keever, Carson C. ; Puritz, Jonathan B. ; Harantio, Januar ; Toonen, Robert J. ; Selvakumaraswamy, Paulina ; Grosberg, Richard K. ; et al ( July 2023 , Aquatic Conservation: Marine and Freshwater Ecosystems)

   The diversity and distribution of marine species in eastern Australia is influenced by one of the world's strongest western boundary currents, the East Australia Current, which propels water and propagules poleward, a flow intensifying due to climate change.

   Population genetic structure of the asterinid sea starMeridiastra calcarwas investigated across its range in eastern Australia (12° of latitude, 2,500 km) from northern New South Wales to its poleward‐extending range in Tasmania at the southern edge influence of the East Australia Current.

   Population structure and connectivity ofM. calcarwere examined across six bioregions using six microsatellite loci (nuclear DNA) and the control region (mitochondrial DNA). The potential influence of the extent ofM. calcar's intertidal rock platform habitat was also assessed.

   Genetic structure analysis indicated that the Hawkesbury Shelf contained distinct genetic clusters, whereas the two sites in the Batemans Shelf differed from each other, with Jervis Bay Marine Park having just one genetic cluster. The Manning Shelf, Twofold Shelf, and Bruny bioregions all had similar genetic composition.

   Strong self‐seeding (68–98%) was indicated by microsatellite loci for all bioregions, with lower (0.3–6.5%) migration between bioregions. Poleward (New South Wales to Tasmania) migration was low except from the Manning Shelf (30%).

   Contemporary population connectivity and genetic structure ofM. calcarappear to be influenced by ocean currents, habitat distribution, and its short planktonic larval duration, which was a minimum of 12–14 days, depending on availability of a settlement cue.

   The dominance of unique genetic groups in the Hawkesbury bioregion shows the importance of this region forM. calcarand possibly a diversity of co‐distributed rock platform species. This highlights how important it is to have a large marine park in the Hawkesbury bioregion, which is presently lacking.

    

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4. Conservation genetic assessment of the paleback darter, Etheostoma pallididorsum , a narrowly distributed endemic in the Ouachita Highlands, Arkansas, USA

   https://doi.org/10.1002/aqc.3510  

   McCall, Brittany L. ; Fluker, Brook L. ( March 2021 , Aquatic Conservation: Marine and Freshwater Ecosystems)

   The paleback darter,Etheostoma pallididorsum, is considered imperilled and has recently been petitioned for listing under the Endangered Species Act. Previous allozyme‐based studies found evidence of a small effective population size, warranting conservation concern. The objective of this study was to assess the population dynamics and the phylogeographical history of the paleback darter, using a multilocus microsatellite approach and mitochondrial DNA.

   The predictions of this study were that: paleback darter populations will exhibit low genetic diversity and minimal gene flow; population structure will correspond to the river systems from which the samples are derived; reservoir dams impounding the reaches between the Caddo and Ouachita rivers would serve as effective barriers to gene flow; and the Caddo and Ouachita rivers are reciprocally monophyletic.

   Microsatellite DNA loci revealed significant structure among sampled localities (globalF_st= 0.17,P< 0.001), with evidence of two distinct populations representing the Caddo and Ouachita rivers. However, Bayesian phylogeographical analyses resulted in three distinct clades: Caddo River, Ouachita River, and Mazarn Creek. Divergence from the most recent ancestor shared among the river drainages was estimated at 60 Kya. Population genetic diversity was relatively low (H_e= 0.65; mean alleles per locus,A= 6.26), but was comparable with the population genetic diversity found in the close relatives slackwater darter,Etheostoma boschungi(H_e= 0.65;A= 6.74), and Tuscumbia darter,Etheostoma tuscumbia(H_e= 0.57;A= 5.53).

   These results have conservation implications for paleback darter populations and can be informative for other headwater specialist species. Like other headwater species with population structuring and relatively low genetic diversity, the persistence of paleback darter populations is likely to be tied to the persistence and connectivity of local breeding and non‐breeding habitat. These results do not raise conservation concern for a population decline; however, the restricted distribution and endemic status of the species still renders paleback darter populations vulnerable to extirpation or extinction.

    

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5. Divergence in Body Mass, Wing Loading, and Population Structure Reveals Species-Specific and Potentially Adaptive Trait Variation Across Elevations in Montane Bumble Bees

   https://doi.org/10.1093/isd/ixab012  

   Lozier, Jeffrey D ; Parsons, Zachary M ; Rachoki, Lois ; Jackson, Jason M ; Pimsler, Meaghan L ; Oyen, Kennan J ; Strange, James ; Dillon, Michael E ( September 2021 , Insect Systematics and Diversity)

   Hines, Heather (Ed.)

   Abstract Biogeographic clines in morphology along environmental gradients can illuminate forces influencing trait evolution within and between species. Latitude has long been studied as a driver of morphological clines, with a focus on body size and temperature. However, counteracting environmental pressures may impose constraints on body size. In montane landscapes, declines in air density with elevation can negatively impact flight performance in volant species, which may contribute to selection for reduced body mass despite declining temperatures. We examine morphology in two bumble bee (Hymenoptera: Apidae: Bombus Latreille) species, Bombus vancouverensis Cresson and Bombus vosnesenskii Radoszkowski, across mountainous regions of California, Oregon, and Washington, United States. We incorporate population genomic data to investigate the relationship between genomic ancestry and morphological divergence. We find that B. vancouverensis, which tends to be more specialized for high elevations, exhibits stronger spatial-environmental variation, being smaller in the southern and higher elevation parts of its range and having reduced wing loading (mass relative to wing area) at high elevations. Bombus vosnesenskii, which is more of an elevational generalist, has substantial trait variation, but spatial-environmental correlations are weak. Population structure is stronger in the smaller B. vancouverensis, and we find a significant association between elevation and wing loading after accounting for genetic structure, suggesting the possibility of local adaptation for this flight performance trait. Our findings suggest that some conflicting results for body size trends may stem from distinct environmental pressures that impact different aspects of bumble bee ecology, and that different species show different morphological clines in the same region. 

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