The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa

Abstract
The legume pod borer, Maruca vitrata, is an endemic insect pest that causes significant yield loss to the cowpea crop in West Africa. The application of population genetic tools is important in the management of insect pests but such data on M. vitrata is lacking. We applied a set of six microsatellite markers to assess the population structure of M. vitrata collected at five sites from Burkina Faso, Niger and Nigeria. Observed polymorphisms ranged from one (marker 3393) to eight (marker 32008) alleles per locus. Observed and expected heterozygosities ranged from 0.0 to 0.8 and 0.0 to 0.6, respectively. Three of the loci in samples from Nigeria and Burkina Faso deviated significantly from Hardy-Weinberg Equilibrium (HWE), whereas no loci deviated significantly in samples from Niger. Analysis of molecular variance (AMOVA) indicated that 67.3% level of the genetic variation was within individuals compared to 17.3% among populations. A global estimate of F ST=0.1 (ENA corrected F ST=0.1) was significant (Pa=0.05) and corroborated by pairwise F ST values that were significant among all possible comparisons. A significant correlation was predicted between genetic divergence and geographic distance between subpopulations (R2=0.6, P=0.04), and cluster analysis by the program STRUCTURE predicted that co-ancestry of genotypes were indicative of three distinct populations. The spatial genetic variance among M. vitrata in West Africa may be due to limited gene flow, south-north seasonal movement pattern or other reproductive barriers. This information is important for the cultural, chemical and biological control strategies for managing M. vitrata. Copyright © 2012 Cambridge University Press.

Citation
Agunbiade, T. A., Coates, B. S., Kim, K. S., Forgacs, D., Margam, V. M., Murdock, L. L., … Pittendrigh, B. R. (2012). The spatial genetic differentiation of the legume pod borer, Maruca vitrata F. (Lepidoptera: Crambidae) populations in West Africa. Bulletin of Entomological Research, 102(5), 589–599. doi:10.1017/s0007485312000156

Acknowledgements
The project was supported through the Bean/Cowpea Collaborative Research Support Program (CRSP) program with funding from the United States Agency for International Development (USAID). This study was also made possible through support provided to the Dry Grains Pulses CRSP by the Office of Agriculture Research and Technology, Bureau of Food Security, in the United States Agency for International Development, under the terms of grant no. EDH-A-00-07-00 005. Support for USDA-ARS personnel who contributed to this study was provided by the Agricultural Research Service (CRIS Project 3625-22000-017-00D) and the Iowa State University Agriculture and Home Economics Experiment Station (Project 3543).

Publisher
Cambridge University Press (CUP)

Journal
Bulletin of Entomological Research

DOI
10.1017/S0007485312000156

PubMed ID
22717014

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