Genetic Structure of <I>Sesamia nonagrioides</I> (Lefebvre) Populations in the Mediterranean Area

Abstract

The Mediterranean corn borer, Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae), is a major pest of maize in the Mediterranean area. Transgenic Bt maize expressing the Cry1Ab toxin from the bacterium Bacillus thuringiensis can effectively control this pest. The characterization of S. nonagrioides population structure, at a large geographical scale, would provide some insight in decision making for resistance management. The genetic relationships among nine populations from Spain, one from France, one from Italy, three from Greece, and one from Turkey were assessed using Random Amplyfied Polymorphic DNA (RAPD) markers. Populations from France and Spain formed a cluster independent from a cluster of populations collected in Italy, Turkey, and Greece in a unweighted pair-group method with arithmetic average dendrogram constructed from Nei's genetic distances. Average genetic differentiation among samples was significant for all geographical groupings analyzed (F (ST) = 0.160 +/- 0.014 for Spanish populations; 0.133 +/- 0.022 for Spanish and French populations; and 0.095 +/- 0.010 for Greek, Italian, and Turkish populations). Genetic differentiation was also significant for all paired comparisons of populations, including two Spanish populations separated by only 15 km with no apparent geographical barriers. No pattern of isolation by distance was observed among Mediterranean corn borer populations collected in Spain and France. These results suggest a limited genetic exchange between relatively distant S. nonagrioides populations in Europe, which might contribute to decreased rate of spread of resistance alleles once resistance has developed at a certain site.

Genetic Diversity in Apple Fruit Moth Indicate Different Clusters in the Two Most Important Apple Growing Regions of Norway

“…Our results may be comparable to the ones obtained for other Lepidoptera species, e.g., "Sesamia nonagrioides" in Iran and Spain where subpopulations are separated by larger distances than in the present study. In Iran, genetic differentiation was found between two regions (Southern and Southwestern Iran) separated by 500 km [49], while in Spain, high genetic differentiation was observed between regions separated by distances of 1000 km [50]. AFLP data analysis of individual male and female did not reveal any marker specific for sex determination, and clustering analyses of males and females did not show any particular pattern.…”

Phylogeography of Sesamia nonagrioides (Lepidoptera: Noctuidae) in Iran inferred from mitochondrial DNA

“…It is worth saying that the sampling areas in southern Europe covered more geographical gradient and range of over 3000 km 2 , whereas in our study, sampling localities in South and Southwest Iran were limited to a distance of 500 km 2 . Previous studies revealed high levels of differentiation among geographically close populations of S. nonagrioides, which could be indicative of the sedentary nature and moderate dispersal behavior of this pest, even when no remarkable geographical barriers exist (De La Poza et al 2008, Cherghali et al 2015. Ecological observations regarding flight behavior and dispersal capacity of S. nonagrioides validate the low dispersal ability of this pest too , Eizaguirre et al 2004).…”

“…Pesticides are used by farmers in the case of heavy damage to maize and rice. Management practices of S. nonagrioides in Iran ignore the possible existence of genetic diversity among populations of this pest and its range of distribution.The species S. nonagrioides, is considered one of the most important pests of maize in many countries around the Mediterranean region where it is known as the Mediterranean corn borer or corn stalk borer (De La Poza et al 2008). This pest has been traditionally regarded as a rather sedentary pest , Eizaguirre et al 2004, Margaritopoulos et al 2007), likely to develop genetic isolation between geographical regions.…”

“…This pest has been traditionally regarded as a rather sedentary pest , Eizaguirre et al 2004, Margaritopoulos et al 2007), likely to develop genetic isolation between geographical regions. Genetic differentiation between S. nonagrioides populations in European countries has been reported using different molecular markers (Bues et al 1996, Kourti 2006, Leniaud et al 2006, Margaritopoulos et al 2007, De La Poza et al 2008. reconstructed the evolutionary history of Palaearctic and Sub-Saharan populations of S. nonagrioides using one nuclear and two mitochondrial genes and concluded that the isolated Iranian population appears to have recently originated from a population of eastern Europe origin.…”

Susceptibility to the Cry1F Toxin of Field Populations of Sesamia nonagrioides (Lepidoptera: Noctuidae) in Mediterranean Maize Cultivation Regions

“…Field populations were grouped according to two criteria: 1) by geographical areas, Western Mediterranean (WM) (Spanish and French populations) versus Eastern Mediterranean (EM) (Italian, Greek and Turkish populations), because we found in a previous population genetic study that S. nonagrioides populations from these countries were clustered in these two groups (de la Poza et al 2008); and 2) by history of exposure to Bt plants (Spanish versus the other populations). Mortality values of each area at different concentrations were pooled and analyzed together by probit analysis as described above, to obtain LC 50 and LC 90 values and their 95% Þducial limits.…”