Location: Screwworm ResearchTitle: Population structure, genetic variability, and gene flow of the bean leaf beetle, Cerotoma trifurcata, in the Midwestern United States) Author
Submitted to: Journal of Insect Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/28/2013
Publication Date: 5/2/2014
Publication URL: http://handle.nal.usda.gov/10113/59442
Citation: Tiroesele, B., Skoda, S.R., Hunt, T.E., Lee, D.J., Molina-Ochoa, J., Foster, J.E. 2014. Population structure, genetic variability, and gene flow of the bean leaf beetle, Cerotoma trifurcata, in the Midwestern United States. Journal of Insect Science. 14:62. Interpretive Summary: The bean leaf beetle (BLB) is an important pest of legumes, particularly soybeans, in the U.S. Currently there have been no large-scale studies on the population genetics of BLB. Increased understanding of the genetics of the BLB would be beneficial for developing a pest management strategy for this pest. For this study, samples of 15 – 30 individuals were taken from twenty five subpopulations from soybean producing states in the Midwest and used in molecular genetic analysis. Amplified fragment length polymorphism – polymerase chain reaction generated 175 genetic markers. The distribution of these markers from individuals within and between subpopulations was analyzed. Results indicated that the majority of genetic variation was within subpopulations, that the migration rate of BLB was sufficient to maintain genetic heterogeneity, and there was no relationship between geographic distance and genetic distance. These findings indicate that, in the Midwest, BLB is one large, interbreeding population. Therefore, once pest management strategies are developed they should be equally effective across this region.
Technical Abstract: Bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is a common pest of soybean in the Midwest. However, there are currently no studies on the genetic variability of C. trifurcata. This study examined 15-30 individuals from 25 subpopulations to determine genetic variability and gene flow within and among C. trifurcata subpopulations in the Midwest-US using 175 markers generated with amplified fragment length polymorphism. The AMOVA results indicated that the majority of genetic variation was from within subpopulations and only a small amount of the total variation was attributed to the variation among the subpopulations. The GST for the entire C. trifurcata population indicated that the majority of genetic variation was found within the subpopulations, further supporting the AMOVA results. The average gene flow among the C. trifurcata subpopulations was high. The mantel tests revealed no indication of correlation between geographical and genetic distance for all the C. trifurcata subpopulations. The findings revealed that the subpopulations of C. trifurcata in the Midwest-US are genetically heterogeneous and part of a large, interbreeding population.