Solitary Bees Are More Efficient Pollinators of Sponge Gourd than Giant honeybees and Syrphid Flies

Abstract

Cucurbits comprise a vast group of vegetables grown worldwide, including Pakistan. The sponge gourd (Luffa aegyptiaca) is a summer vegetable in Asia. Because of its monoecious nature, sponge gourd necessitates more pollination, and fruit production occurs only in the presence of insect pollinators. This study compared the foraging behavior and pollination effectiveness of the most abundant sponge gourd floral visitors, including five solitary bees and a giant honeybee, Apis dorsata. The foraging behavior was assessed regarding visitation rate, visitation frequency, and time spent per flower, while pollination effectiveness was assessed regarding pollen deposition and fruit set in a single visit. The bees constituted 91% of total pollinator abundance, followed by the flies (8%). Apis dorsata was the most abundant visitor, followed by Xylocopa sp., Lassioglossum sp., and Amegilla sp. Solitary bees, including Amegilla sp. and Nomia sp., demonstrated greater single-visit efficiency in pollen deposition and fruit set than A. dorsata and syrphid fly. Conservation of Amegilla sp. and Nomia sp. can enhance fruit production for sponge gourd and other vegetables cultivated in Punjab, Pakistan, by providing floral resources and nesting places.