Nesting biology of an Oriental carpenter bee, Xylocopa (Biluna) nasalis Westwood, 1838, in Thailand (Hymenoptera, Apidae, Xylocopinae)

Abstract

The biological study of wild non-Apis bees can provide useful information that may help with the pollination of food crops and native plants in areas where the keeping of honey bee colonies is restricted or affected by CCD. Here, we describe the nesting biology of the Oriental large carpenter bee, Xylocopa (Biluna) nasalis Westwood, 1838. An aggregation of more than 80+ bamboo nests of X. nasalis was discovered in Suan Pheung district, Ratch Buri province, Thailand on the 25th of May 2012. We collected 27 nests from the site to dissect, measure the external and internal nest architecture, and analyze the pollen composition of the pollen masses. X. nasalis constructs linear unbranched nests with nest entrance mostly located at the open-end of the bamboo culms. The nest length and the branch diameter of the nest entrance (excluding nesting edge) are 25.40 ± 6.95 cm and 17.94 ± 6.00 mm, and the maximum number of provisioned cells is 8. A biased sex ratio of 8♀: 1♂ is reported, with up to 7 adults inhabiting in a single nest. 29 pollen types were identified from 14 pollen masses using an acetolysis method and visualization under both light microscope and scanning electron microscope. 13 pollen types were considered as major pollen sources (contribute ≥ 1% in total pollen volume); however, only 10 can be identified to family and generic levels. The dominant pollen sources are of the families Elaeagnaceae (Elaeagnus cf. latifolia), Euphorbiaceae (Croton), Fabaceae (Senna siamea and Cassia), Fagaceae (Lithocarpus and Castanopsis), and Lythraceae (Trapa) which are mostly native to the region of Southeast Asia. The nesting architectural details should prove to be beneficial to beekeepers and researchers who are interested in trapping and studying X. nasalis, and the polylectic behavior of X. nasalis can be highly valuable for future crop pollination strategies, particularly for plants that require sonication of their poricidal anthers.