Weak spatial-genetic structure in a native invasive, the southern pine beetle ( Dendroctonus frontalis ), across the eastern United States

PeerJ

article

Ryan C. Garrick¹  Ísis C. Arantes¹  Megan B. Stubbs¹  Nathan P. Havill² 

[1] Department of Biology, University of Mississippi;Northern Research Station

关键词: Coleoptera;    Genotypic cluster;    Isolation by distance;    Microsatellites;    Range expansion;    Sex biased dispersal;   

DOI  :  10.7717/peerj.11947

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The southern pine beetle, Dendroctonus frontalis, is a native pest of pine trees that has recently expanded its range into the northeastern United States. Understanding its colonization, dispersal, and connectivity will be critical for mitigating negative economic and ecological impacts in the newly invaded areas. Characterization of spatial-genetic structure can contribute to this; however, previous studies have reached different conclusions about regional population genetic structure, with one study reporting a weak east-west pattern, and the most recent reporting an absence of structure. Here we systematically assessed several explanations for the absence of spatial-genetic structure. To do this, we developed nine new microsatellite markers and combined them with an existing 24-locus data matrix for the same individuals. We then reanalyzed this full dataset alongside datasets in which certain loci were omitted with the goal of creating more favorable signal to noise ratios. We also partitioned the data based on the sex of D. frontalis individuals, and then employed a broad suite of genotypic clustering and isolation-by-distance (IBD) analyses. We found that neither inadequate information content in the molecular marker set, nor unfavorable signal-to-noise ratio, nor insensitivity of the analytical approaches could explain the absence of structure. Regardless of dataset composition, there was little evidence for clusters (i.e., distinct geo-genetic groups) or clines (i.e., gradients of increasing allele frequency differences over larger geographic distances), with one exception: significant IBD was repeatedly detected using an individual-based measure of relatedness whenever datasets included males (but not for female-only datasets). This is strongly indicative of broad-scale female-biased dispersal, which has not previously been reported for D. frontalis, in part owing to logistical limitations of direct approaches (e.g., capture-mark-recapture). Weak spatial-genetic structure suggests long-distance connectivity and that gene flow is high, but additional research is needed to understand range expansion and outbreak dynamics in this species using alternate approaches.

【 授权许可】

CC BY