Integrative Taxonomic Assessment of the Lychee Stink Bug (Tessaratoma javanica) from Jharkhand, India Using Morphological Characters and COI Gene Barcoding

An integrative taxonomic study of the lychee stink bug Tessaratoma javanica (Hemiptera: Tessaratomidae) was conducted using morphological characters and mitochondrial cytochrome c oxidase subunit I (COI) gene barcoding on specimens collected from 10 locations across Jharkhand, India. All examined adults displayed consistent diagnostic morphological features, including a large shield-shaped body, expanded pronotum, prominent triangular scutellum, five-segmented antennae, and a robust rostrum extending to the mid-coxae, indicating morphological uniformity among populations. COI gene fragments (612–690 bp) were successfully amplified and sequenced. BLASTn analyses confirmed species identity through high similarity with reference T. javanica sequences. Ten validated COI sequences were deposited in the DDBJ database under accession numbers LC911186–LC911195. Nucleotide composition exhibited a marked AT bias, with mean values of T(U) = 33.1%, A = 33.1%, C = 17.5%, and G = 16.4%. Genetic distance analysis revealed very low intraspecific divergence, indicating strong genetic homogeneity across geographically separated populations. Phylogenetic analyses using Maximum Likelihood, Neighbor-Joining, and Minimum Evolution methods consistently grouped all specimens into a single well-supported monophyletic clade without evidence of cryptic diversity. The congruence between morphological and molecular data confirms the taxonomic stability of T. javanica in Jharkhand and provides a reliable reference framework for pest identification, biodiversity assessment, and future population genetic studies.