Abstract

Sunflower is a bee loving crop. The foraging behaviour of Apis dorsata L. was studied in comparison with Indian bee (A. cerana indica) and stingless bee (Trigona sp.) on this crop. A.dorsata outnumbered the other two bee species on capitulum after anther dehiscence during all the three stages of blooming. A. dorsata population varied at different hours of the day showing a bimodal distribution. The foragers were active from 10.00 to 11.00 am in the forenoon and 2.00 to 3.00 pm in the afternoon. Foraging behaviour showed distinct variation according to the floral reward collected. A.dorsata alone was found to tap the nectar fully due to its longer lapping tongue. Exclusive pollen collectors were rare. Majority of the foragers collected both pollen and nectar. Exclusive nectar foragers intentionally discarded the pollen load before final take off. Rains adversely affected the time of commencement and cessation of foraging. Among all the bee species studied, A.dorsata was the best pollinator of sunflower based on pollinator efficiency index. Wild honey bees like A.dorsata have to be conserved in crop ecosystem where planned pollination with hive bees is not in vogue.

Keywords: Apis dorsata, Apis cerana indica, pollinator, honey bees, Helianthus annuus