Floral nectar (FN): drivers of variability, causes, and consequences

This review article aims to compile updated information on the drivers of variability in floral nectar (FN), focusing mainly on concentration, volume, and metabolites. The study also seeks to organize and consolidate existing data on physicochemical variables while proposing new directions for future research. The primary conclusion of this study is that FN is not an ideally static fluid in terms of its physicochemical composition. Instead, it exhibits substantial plasticity and diversity while maintaining some regularities throughout its pre- and post-secretory processes. Therefore, a comprehensive analysis of FN—incorporating its molecular, physiological, environmental, genetic, and ecological attributes—is imperative for a holistic understanding of its drivers. Furthermore, the study determines that the phenomenon of FN variation is significantly more intricate than initially perceived. Despite considerable progress, new drivers and mechanisms of variability continue to emerge, signifying a massive knowledge gap in our pursuit of a comprehensive understanding of this phenomenon and its extensive implications for pollinators.