Secondary Metabolites in Nectar-Mediated Plant-Pollinator Relationships

In recent years, our understanding of the complex chemistry of floral nectar and its ecological implications for plant-pollinator relationships has certainly increased. Nectar is no longer considered merely a reward for pollinators but rather a plant interface for complex interactions with insects and other organisms. A particular class of compounds, i.e., nectar secondary compounds (NSCs), has contributed to this new perspective, framing nectar in a more comprehensive ecological context. The aim of this review is to draft an overview of our current knowledge of NSCs, including emerging aspects such as non-protein amino acids and biogenic amines, whose presence in nectar was highlighted quite recently. After considering the implications of the different classes of NSCs in the pollination scenario, we discuss hypotheses regarding the evolution of such complex nectar profiles and provide cues for future research on plant-pollinator relationships.

Automated summary

In recent years, there has been an increased understanding of the complex chemistry of floral nectar and its ecological implications for plant-pollinator relationships. Nectar is now seen as more than just a reward for pollinators, but rather a platform for complex interactions with insects and other organisms. This review aims to provide an overview of our current knowledge of nectar secondary compounds (NSCs), including recently highlighted aspects such as non-protein amino acids and biogenic amines. It also discusses the implications of these NSCs in the pollination scenario, hypotheses regarding the evolution of complex nectar profiles, and potential cues for future research on plant-pollinator relationships.