INTEGRATING MORPHOMETRIC AND GENETIC ANALYSES OF POPULATION DIVERGENCE IN APIS CERANA INDICA (INDIAN BEE) FROM PAPANASAM TALUK, TAMIL NADU, INDIA

Abstract

Taxonomic resolution within the genus Apis is often complicated by morphological variability and phenotypic plasticity, with obscure species and subspecies boundaries. This study aimed to establish clear taxonomic evidence for cavity-nesting Apis cerana indica from Papanasam Taluk, Tamil Nadu, by integrating classical and geometric morphometrics with mitochondrial DNA barcoding. Forty-five worker bees from three colonies were analysed for 34 morphometric traits along with forewing shape using 19 landmarks with multivariate ordinations. Molecular identification was performed through COI gene sequencing and phylogenetic analysis. Morphometric data revealed strong inter-colony similarity with conserved wing shape, while COI sequences showed high conservation (0.94) and tight clustering within A. cerana indica (0.00–0.17), with clear divergence from A. dorsata, A. florea, and A. mellifera (10-13%). Regional populations from Tamil Nadu, Orissa, and Calicut were homogeneous, whereas Thrissur, Bangalore, and Shillong exhibited moderate divergence (4.7-5.5%). Concordant morphometric and molecular evidence confirms the regional identity of A. cerana indica, providing a robust baseline for breed purity, genetic conservation, and future ecological and applied research in tropical agroecosystems.