Multiple locus sequence analysis of alfalfa weevil (Hypera postica (Gyllenhal))

The Eastern, Western and Egyptian strains of the alfalfa weevil have been introduced to North America on at least three different occasions. Due to subtle ecological differences between strains, crop management strategies have to be adjusted to achieve an appropriate degree of pest control. As a result, management becomes complicated when two or more strains are present in the same area. Due to difficult morphological identification among strains, restriction pattern analysis of mitochondrial markers has been used for strain identification in the past. Our work confirms and extends those previous findings by sequencing and comparing over 4.5 Kb of two mitochondrial and three nuclear loci from the three strains of alfalfa weevil present in North America. Our sequence data confirms a minimal difference between the Eastern and the Egyptian strains when both mitochondrial and nuclear markers were analyzed. Sequence from the nuclear Arginine Kinase gene and the 18s rRNA separate all three strains from other weevils, but not from each other. However, a few polymorphisms found on the nuclear ITS region that may allow separation between all three strains.