Wireworm (Coleoptera: Elateridae) genomic analysis reveals putative cryptic species, population structure, and adaptation to pest control
Andrews, K.R., Gerritsen, A., Rashed, A., Crowder, D.W., Rondon, S.I., van Herk, W.G., Vernon, R., Wanner, K.W., Wilson, C.M., New, D.D., Fagnan, M.W., Hohenlohe, P.A., Hunter, S.S. (2020). Wireworm (Coleoptera: Elateridae) genomic analysis reveals putative cryptic species, population structure, and adaptation to pest control. Communications Biology, [online] 3(1), http://dx.doi.org/10.1038/s42003-020-01169-9
Plain language summary
Wireworms, the larvae of click beetles (Coleoptera: Elateridae), are agricultural pests that are causing increasing economic damage to cereal, potato, and vegetable crops worldwide. In BC, Alberta, Montana, and the Pacific Northwest, some of the most important pest species belong to the genus Limonius, particularly L. californicus, L. infuscatus, and L. canus. The biology of these species is poorly understood, and they are difficult to separate morphologically. This paper presents results of a project led by the University of Idaho, in which specimens of all three species, collected from different Provinces and States, were sequenced and compared. This produced the first genome assembly of a pest wireworm (L. californicus), and, using genome-wide markers (RADseq) and genome skimming, allowed for an investigation of the population structure and phylogenetic relationships of these three species across this area. It appears that both L. californicus and L. infuscatus are comprised of genetically distinct but morphologically indistinguishable groups, and these species could therefore be considered cryptic species complexes. Genome scans for selection also provide evidence for adaptation associated with different pesticide treatments in an agricultural field trial for L. canus. These results demonstrate that genomic tools can help in the development of effective wireworm control strategies. These data can potentially be used to develop species-specific primers that can be used for rapid, PCR-based species identification. Together with ongoing research, led by AAFC, into the development of new sex pheromones for these species, such ID tools will significantly increase our ability to manage these pests.
The larvae of click beetles (Coleoptera: Elateridae), known as “wireworms,” are agricultural pests that pose a substantial economic threat worldwide. We produced one of the first wireworm genome assemblies (Limonius californicus), and investigated population structure and phylogenetic relationships of three species (L. californicus, L. infuscatus, L. canus) across the northwest US and southwest Canada using genome-wide markers (RADseq) and genome skimming. We found two species (L. californicus and L. infuscatus) are comprised of multiple genetically distinct groups that diverged in the Pleistocene but have no known distinguishing morphological characters, and therefore could be considered cryptic species complexes. We also found within-species population structure across relatively short geographic distances. Genome scans for selection provided preliminary evidence for signatures of adaptation associated with different pesticide treatments in an agricultural field trial for L. canus. We demonstrate that genomic tools can be a strong asset in developing effective wireworm control strategies.