FORAGING BEHAVIOUR OF HONEYBEES IN SEED PRODUCTION OF BRASSICA OLERACEA VAR. ITALICA PLENCK

Work on ascertaining the diversity and foraging behaviour of pollinators and their impact on seed yield in broccoli was carried out. The blooming crop of the broccoli was visited by 17 species of insects belonging to 6 orders and 11 families of class insects. Hymenopterans were the most doi'iinant visitors constituting 98.18 per cent of the insect.visitors, followed by others (1.82%). Among the hymenopteran species, Apis dorsata F. was highest in number (47.88%) among the visitors of broccoli flower, followed by'Apis mellijera L. (30.65%), Apis cerana F. (16.31%), Apis florea F. (3.32%) and others (1.82%). The mean foraging rate irrespective of different dates and times was the highest for A. dorsata (5.35 t 0.33 flowers/min) followed by that of A. mellifera (4.87 +/- 0.34 flowers/min), A. cerana (1.75 +/- 0.23 -flowers/min) and A. florea (0.11 +/- 0.09 flowers/min). The number of flower visit per minute at different time interval was highest in case of A. dorsata, followed by A. mellifera, A.cerana and A. florea. The studies on diurnal foraging speed (time spent by bees in seconds) by honeybees at different times and dates indicated that A. dorsata had the highest foraging speed across different dates and times followed by A. mellifera, A. creana and A. florea. Mean time spent irrespective of different dates and times was the highest for A. dorsata (5.20 +/- 0.5.20 sec) followed. by that of A. niellifera (3.87 +/- 0.22 sec), A. cerana (1.72 +/- 0.23 sec) and A. florea (1.05 +/- 0.58 sec). The foraging speed was the highest in case of A. dorsata followed by A. tnellifCra,..4. cerana and A. florea.on broccoli blooms. Results on the quantitative parameters of yield 'such as numbers of siliqua per. plant, number of seeds per siliqua, seed weight and seed yield showed significant differences under different mode of pollination in the broccoli seed crop.