Morphometric characterization of Tetragonula iridipennis Smith (Hymenoptera: Apidae) from diverse nesting habitats in Karnataka, India

This study explores the nesting habitat characteristics and morphometric variations of the stingless bee Tetragonula iridipennis Smith across four distinct locations in Karnataka, India. Ten feral colonies were examined for nesting traits, while morphometric analysis was conducted on specimens from Nrupathunga University (Bangalore), UAS-GKVK (Bangalore), Honnadevipur, and Harohalli. Nesting observations revealed a preference for varied substrates—including stone structures and residential buildings—primarily situated within educational and urban areas. Entrance tubes displayed notable variability, with lengths ranging from 0.5 to 1.5 cm and widths from 0.3 to 1.0 cm. Analysis of 29 morphometric parameters highlighted statistically significant differences among populations, with mean body length ranging from 3.87 mm to 4.07 mm. These findings underscore the ecological adaptability and morphological diversity of T. iridipennis, reinforcing its role as a vital indigenous pollinator in diverse environments. Keywords: Stingless bees, Tetragonula iridipennis, morphometry, nesting behavior, Karnataka, pollinators