Abstract
Decline of bee pollinators results in insufficient crop pollination, lowering the quality, and quantity of crop yields. In Sri Lanka, there is a lack of research on the importance of local bees in sesame pollination. The current study investigated the role of Sri Lankan native bees in pollinating sesame and increasing crop productivity. The research was carried out at Meewatura Farm, located in the Kandy District of the University of Peradeniya, Sri Lanka. Three pollination trials were conducted to determine the contribution of bees to enhance seed number, weight, and germinability of sesame, selecting 100 sesame flower buds randomly for each trial. One set of flowers buds was covered to prevent bee visits; another set was kept open to enable bee visits, while the third set was pollinated by hand. Six bee species; Systropha tropicalis, Gnathonomia nasicana, Lasioglossum serenum (F: Halictidae), Apis cerana, Amegilla comberi, and Ceratina binghami (F: Apidae), were identified as visitors of sesame flowers. Period of stigma receptivity (0700 - 1100 h) and pollen availability (0640 - 1000 h) coincided with the highest bee activity period from (0830 - 1030 h). Significant differences (p < 0.05) in seed number, seed weight, and seed germinability were detected among the three trials. Open flowers had significantly higher seed number (p = 0.0001) and seed germinability (p = 0.0001) than covered flowers. Although there was no significant difference in seed weight between seeds produced from open flowers and covered flowers, the seed weight of hand-pollinated flowers was significantly higher than the other two treatments (p = 0.0001). This pioneering study highlights the role of native bees of Sri Lanka to enhance production in S. indicum in terms of seed number and quality.