Genotyping‐by‐sequencing approach indicates geographic distance as the main factor affecting genetic structure and gene flow in Brazilian populations of Grapholita molesta (Lepidoptera, Tortricidae)

Abstract

The oriental fruit moth Grapholita molesta is one of the major pests of stone and pome fruit species in Brazil. Here, we applied 1226 SNPs obtained by genotyping-by-sequencing to test whether host species associations or other factors such as geographic distance structured populations of this pest. Populations from the main areas of occurrence of G. molesta were sampled principally from peach and apple orchards. Three main clusters were recovered by neighbor-joining analysis, all defined by geographic proximity between sampling localities. Overall genetic structure inferred by a nonhierarchical amova resulted in a significant ΦST value = 0.19109. Here, we demonstrate for the first time that SNPs gathered by genotyping-by-sequencing can be used to infer genetic structure of a pest insect in Brazil; moreover, our results indicate that those markers are very informative even over a restricted geographic scale. We also demonstrate that host plant association has little effect on genetic structure among Brazilian populations of G. molesta; on the other hand, reduced gene flow promoted by geographic isolation has a stronger impact on population differentiation.

Evidence of high-altitude adaptation in the glyptosternoid fish, Creteuchiloglanis macropterus from the Nujiang River obtained through transcriptome analysis

“…In addition, a Discriminant Analysis of Principal Components (DAPC) was applied to provide a visual evaluation of the genetic structure of these populations of C. macropterus , using the R package adegenet [ 28 ]. The sampling localities were used as prior groups, and all loci that were detected with SNPs were used as inputs [ 29 ].…”

Susceptibility of Grapholita molesta to insecticides in Brazil

“…However, the low gene flow between G. molesta populations (SILVA-BRANDÃO et al, 2015) may contribute for the occurrence of evolution of resistance more quickly in local populations, since there is no introduction of susceptibility alleles (susceptible individuals) in the population by increasing the frequency of resistant individuals on site (KANGA et al, 2003). Therefore, the use of insecticides in apple and peach orchards should be done with caution, once that the molecules of insecticides available or registered for the G. molesta management are practically the same for the two crops.…”

“…In Brazil, this strategy can also help delay or avoid the evolution of resistance in populations of G. molesta due the populations present low genetic variability (SILVA-BRANDÃO et al, 2015). However, the low gene flow between G. molesta populations (SILVA-BRANDÃO et al, 2015) may contribute for the occurrence of evolution of resistance more quickly in local populations, since there is no introduction of susceptibility alleles (susceptible individuals) in the population by increasing the frequency of resistant individuals on site (KANGA et al, 2003).…”

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of theAnastrepha fraterculuscomplex (Diptera: Tephritidae)

“…Possible causes for its divergence may be the geographical distance between PIR and the Southern populations or habitat fragmentation of the Atlantic forest biome where the populations studied are found, which would significantly reduce the gene flow between them. For instance, geographic isolation was more important than host-plant association in determining genetic structure of Grapholita molesta (Lepidoptera, Tortricidae) populations from Southeastern and Southern Brazil (Silva-Brandão et al, 2015). Besides being found in the same Brazilian regions, both A. fraterculus and G. molesta are polyphagous insects with high dispersion potential and, consequently, might be subjected to similar forces that ultimately cause populational differentiation.…”