DNA Barcoding Reveals Genetic Footprints of Multiple Putative Orthoptera Species (Insecta) in Assam, Northeast India

The orthopterans (grasshoppers, crickets, etc.) comprise one of the large orders of the class Insecta. As phytophagous some species of this order become important agricultural pests. Due to change in behaviour and appearance many of these insects seldom caused confusion in taxonomic identification of species. These confusions can largely be resolved by molecular characterization and DNA markers of the species. In this background a good number of orthopteran specimens from different localities and habitats of Assam state were selected for DNA barcode sequencing. A total of 1661 barcodes representing 369 species, including samples obtained from Northeast India, were evaluated for species delineation using several genealogical techniques like, Kimura 2-Parameter, Neighbor Joining, and Maximum Likelihood. Herein, we found 70% of the orthopteran species as straightforward instances, whereas 20 species exhibited cryptic diversity with intraspecies distances greater than the computed species delimitation threshold, i.e., 4.36%+ 0.9%. The remaining 90 species displayed interspecific genetic distance that is significantly lower than the estimated threshold, revealing ambiguous diversity. We also explored four putative species. This study has given new inputs to the taxonomic understanding of the Orthoptera by exploration of cryptic species. It points out also to the importance of DNA barcoding and molecular characterization of species, apart from the morphometric characteristics, in developing integrative taxonomy of insect species.