Effects of Time of Day, Inflorescence Height, and Light–Shade Conditions on Plant–Pollinator Interactions in Lychee (Litchi chinensis Sonn.) in West Bengal, India

Lychee, an entomophilous fruit crop cultivated in tropical and subtropical regions, depends heavily on pollination services for optimal fruit yield and the economic sustainability of farmers. However, information on its pollinator interactions remains limited. This study was conducted over three flowering seasons to document the pollinator assemblage of lychee and examine variation in their activity under different physical conditions, including time of day, panicle height, and light–shade environments. Several insects (here, 47, including many butterflies, bees and flies) were recorded as flower visitors of lychee. The most effective pollinators were Apis cerana, Apis dorsata, Apis florea, Braunsapis mixta, and Tetragonula pagdeni. Pollinator abundance, species richness, diversity, and foraging traits (e.g., flower visitation rate and flower handling time) varied with daytime, inflorescence height, and light availability (light versus shade). Greater abundance, richness, and diversity were documented between 8:00 and 12:00 h, at mid-canopy height (2–6 m), and on well-lit inflorescences. Flower visitation rate was higher under these conditions, whereas flower handling time was lower. This study uncovered the key pollinators of lychee and demonstrated that plant–pollinator interactions vary across different physical conditions. These findings may help to improve pollinator management and enhance pollination services in lychee cultivation.