Foraging Niche Overlap Among Exotic Honeybees (Apis mellifera) and Native Honeybees (Apis cerana, Apis dorsata and Apis florea), Considering Pollen Sources in the Rarh Regions of West Bengal, India

Several honeybee species can coexist within a given geographical region; however, their interactions and the extent to which their foraging niches overlap remain poorly understood. To address this gap, we assessed niche overlap among four honeybee species (Apis cerana, Apis dorsata, Apis florea and Apis mellifera) in West Bengal, India, using palynological analysis of corbicular pollen loads. The homogeneous composition of individual corbicular loads indicated flower constancy in all species. A wide range of pollen types was recorded for each species, confirming their polylectic foraging behaviour. Although the level of pollen diversity in their diet did not differ among species, it did vary seasonally. Vital pollen sources (including Acacia auriculiformis, Borassus flabellifer, Brassica juncea, Bridellia retusa, Cocos nucifera, Coriandrum sativum, Eucalyptus tereticornis, Lannea coromandelica and Sesamum indicum) were shared by all four species, and their pollen-foraging niches showed significant overlap in every season. Considering the floral traits of the plants visited, all honeybee species behaved as generalist flower visitors. This study quantifies foraging niche overlap among honeybee species and identifies common floral resources shared by the exotic Apis mellifera and native honeybees. Such insights will assist in honeybee management, biodiversity conservation, and the enhancement of ecosystem services and stability.