Floral traits and chemical cues associated with rock bee (Apis dorsata Fabricius) for the host selection in West Bengal, India

In the present work, bee foraging plants were determined by palynological analysis of colony stored samples (honey and pollen) of Apis dorsata collected from southern West Bengal, India. Then flowering phenology and pollen morphologies were described to evaluate the forage preference of the bee species. In addition, chemical cues were analysed using gas chromatography-mass spectrometry (GC-MS). Foraging strategy of the bee species was profitable in that almost all the bee-visited plants were utilised for both nectar and pollen sources. The bee species became generalist visitor of several plants having diverse life form, flower characters and pollen morphologies. However, most of the bee-visited plants were of trees with synchronous type of flowering. Most plants had small-sized, yellow, cream and white coloured flowers and pollen was openly presented. We did not find any patterns in the morphological traits of bee collected pollen, though the pollen types were predominantly of medium sized with trizonocolporate apertural pattern and reticulate surface ornamentation. Floral volatile organic compounds (VOCs) of bee visited plants were also diversified. Compounds frequently found in the floral VOC bouquets were amphetamine-3-methyl; butane, 2-cyclopropyl; 2,3-butanediol; cyclohexan, 1-methyl-5-(1-methylethyl); d-limonene; methyl (2E)-2-methoxy-2-butenoate; phenol, 4-[2-(methylamino)ethyl]; phthalic acid, di(2-propylpentyl)ester; propanamide, N-(aminocarbonyl) and pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl). In conclusion, floral traits and chemical cues of plants influence the host selection specificity (to collect floral rewards) of the rock bees.