Population structure and variation in Ceutorhynchus obstrictus and C. neglectus (Coleoptera: Curculionidae)

Ceutorhynchus weevils comprise a worldwide genus with many economically important species. Introduced from Europe over 70 years ago, the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), is a major pest of canola in North America, and has only recently invaded Canada east of British Columbia. I used mtDNA sequence data to examine population structure and the historical processes responsible for that structure, using both nested clade analysis and analysis of molecular variance, in order to determine the European source for the North American invasions. I also examined the population structure of Ceutorhynchus neglectus (Blatchley), which is native to North America, using both nuclear and mitochondrial DNA. I then compared the variation within these two Ceutorhynchus weevils to variation found in other weevil species. Additionally, I used parsimony analysis to construct a phylogeny of 10 Ceutorhynchus species to examine interspecies relationships and interspecific variation.