Pollination Unveiled: Exploring Floral Rewards

The first evidence of plant–pollinator interaction dates back to the late Cretaceous (~80 mya). This interplay has been traditionally reported as mutually beneficial because, as sessile organisms, plants gain access to the benefits of cross-pollination, whilst pollinators are rewarded with food, shelter, or nest materials. More recently, this classic bipartite view has been challenged by the widespread presence of microbes in floral rewards. Such widespread presence—along with changes in the reward quantity and quality—adds considerable complexity to our attempts to elucidate the ecological functions of floral rewards. Similarly, the discovery of a plethora of secondary metabolites with a defensive role in floral rewards seems contradictory to enticing floral visitors. In fact, as all actors involved in plant–microbe–pollinator interactions are under simultaneous and reciprocal selective pressures, the presence of a series of conflicts and trade-offs raises many exciting new questions to be addressed in further research. Here, besides offering an updated review on pollinator rewards, we offer a new series of ready-to-use protocols and some considerations on the potential limitations encountered while studying the behavior of flower visits in wild bees. Our hope is to provide young researchers, students, and technicians with a handy and comprehensive overview to successfully approach research on pollination biology.