Contrasting genetic diversity and intra-population polymorphism of the invasive pest Henosepilachna vigintioctopunctata (Coleoptera, Coccinellidae): A DNA barcoding approach

Henosepilachna vigintioctopunctata (Coleoptera: Coccinellidae) is one of the most important pests attacking Solanaceae crops in Asian countries. Despite its agricultural importance, little information is available on the molecular ecology and evolution. In this study, we used DNA barcoding to explore the genetic diversity and intra-population polymorphisms of H. vigintioctopunctata. Haplotype analysis of the partial COI gene sequences of H. vigintioctopunctata from four localities in South India and other globally available haplotypes revealed two genetically distinctive lineages. The TCS haplotype network with the main clusters G1, G2, G4 and G6 represented intra-population polymorphism among the Indian lineages, while other clusters were differentiated with unique mutational steps. High substitutions in the 1st and 3rd codon suggested the dominance of synonymous substitutions with significant p-values < 0.05, that inferred for purifying selection. The genetic diversity indices Fu's Fs and neutrality index Tajima-D had negative values that implied for recent population expansion and low frequency of polymorphism. Further, high genetic divergences among certain haplotype comparisons evidenced the influence of micro-evolutionary pressures. The threshold value was 1.26%, which was supported by the postulates of 10 × rule. Overall, the study firstly reported the genetic diversity and intra-population polymorphism of H. vigintioctopunctata populations attacking Solanaceae species in Asian countries.