Identification and phylogenetic analysis of fruit borer species of litchi using DNA barcode sequences

Abstract

Fruit borers are the major insect pests of litchi in humid orchard conditions at the time of fruit ripening in Indian subcontinent. The major constraint faced in formulating any management strategies against the borer is the difficulty in identification of the correct species. The litchi fruit borer has low intraspecific variation among the existing borer populations. Molecular approaches have been used to identify various species. In the present study, partial cytochrome oxidase I (COI) sequences were used to understand the phylogenetic relationship among borer complex, and assess their usefulness to identify and classify unknown borer species collected from litchi orchards. All together, 150 specimens of litchi fruit borer from Bihar and Jharkhand were examined and 2 morphologically similar moths of each genus were used for further analysis. Sequence analysis revealed that the intraspecific and interspecific variations ranged from zero to 10.0% and 4.4 to 20.3%, respectively among fruit borer complex. The phylogenetic analysis showed that the borers specimen used in this study clustered in to distinct species-groups designated as Conopomorpha sinensis Bradley, C. litchiella Bradley, Cryptophlebia ombrodelta Lower and Gatesclarkeana spp. Higher intraspecific genetic variation was observed in Conopomorpha species complex as compared to Cryptophlebia species complex. Present study has clearly demonstrated that DNA barcoding is an efficient and accurate method for identification of coexists of borer complex infestation in litchi fruits. Hence, this approach can play important role in formulating viable pest management strategies.