The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America, and damage resulting from this species has recently expanded southward. Current pest management practices are inadequate and uncertainty regarding geographic origin, as well as limited data on population structure and dynamics across North America impede progress towards more informed management. We examined the genetic divergence between samples collected in North America and northeastern Asia, the assumed native range of C. cinctus using two mitochondrial regions (COI and 16S). Subsequently, we characterized the structure of genetic diversity in the main wheat producing areas in North America using a combination of mtDNA marker and microsatellites in samples collected both in wheat fields and in grasses in wildlands. The strong genetic divergence observed between North American samples and Asian congeners, in particular the synonimized C. hyalinatus, did not support the hypothesis of a recent American colonization by C. cinctus. Furthermore, the relatively high genetic diversity both with mtDNA and microsatellite markers offered additional evidence in favor of the native American origin of this pest. The genetic diversity of North American populations is structured into three genetic clusters and these are highly correlated with geography. Regarding the recent southern outbreaks in North America, the results tend to exclude the hypothesis of recent movement of damaging wheat stem sawfly populations from the northern area. The shift in host plant use by local populations appears to be the most likely scenario. Finally, the significance of these findings is discussed in the context of pest management.
USDA ARS, European Biological Control Laboratory, 810, Avenue du Campus Agropolis, Montferrier sur Lez, France;Montpellier-SupAgro, UMR CBGP, 755 avenue du Campus Agropolis, Montferrier sur Lez, France;Montpellier-SupAgro, UMR CBGP, 755 avenue du Campus Agropolis, Montferrier sur Lez, France;Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States of America;USDA ARS, Beneficial Insects Introduction Research Unit, Newark, DE, United States of America;Systematic Entomology Laboratory, USDA ARS, c/o National Museum of Natural History, Smithsonian Institution, Washington, D.C., United States of America;Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States of America;Département Biologie-Ecologie-Environnement, Laboratoire de Zoogéographie, UMR 5175 CEFE, Université Paul-Valéry Montpellier 3, Route de Mende, Montpellier cedex 5, France;Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, United States of America;Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, United States of America;Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, United States of America;Northern Plains Agricultural Research Laboratory, USDA ARS, Sidney, MT, United States of America;USDA ARS, European Biological Control Laboratory, 810, Avenue du Campus Agropolis, Montferrier sur Lez, France
Recommended Citation:
Vincent Lesieur,Jean-François Martin,David K. Weaver,et al. Phylogeography of the Wheat Stem Sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae): Implications for Pest Management[J]. PLOS ONE,2016-01-01,11(12)