Revisiting Aristotle's observation on bees: High floral constancy is common among bees but it is shaped by the locally abundant flowering species

Abstract

Floral constancy is the tendency of a pollinator to sequentially visit flowers of the same species despite the availability of other rewarding plants. In a phytodiverse community, resource assurance may lead to pollinators displaying floral constancy to the most abundant plant species. We tested this by investigating if pollinators are floral constant on the abundant or the non-abundant plants within a seasonally flowering tropical community. We quantified floral constancy in three social (Apis spp.) and two solitary (non-Apis) Indian native bees using three approaches, that is by manually tracking the bees, analysing their pollen load, and examining pollen sacs of returning bees at their hive. We next examined in Apis cerana indica if constancy in individual bees translated to hive-level constancy. We found that in our community with distinct co-flowering patches, bees were constant to the most abundant species within a localised patch, and not to the most abundant species in the landscape. While the pollen loads from both the social and solitary bees suggested that they show high floral constancy (> 70% uni-dominant pollen), their values differed significantly (p < 0.0001). Finally, approximately 90% of individuals within a hive showed floral constancy (monolectic), but collectively, a hive displayed polylectic foraging. Our findings highlight that the foraging patterns of native pollinators has been understudied and is a critical first step towards connecting reproductive assurances to plant-pollinator dependencies in large landscapes.