Abstract:
Nectar, the main floral reward for pollinators, varies greatly in composition
and concentration. The assumption that nectar quality is equivalent to its
sugar (energy) concentration is too simple. Diverse non-sugar components,
especially amino acids and secondary metabolites, play various roles in
nutrition and health of pollinators. Many nectar compounds have indirect
effects by altering the foraging behaviour of pollinators or protecting them
from disease. This review also emphasizes the water component of nectar,
often ignored because of evaporative losses and difficulties in sampling
small nectar volumes. Nectar properties vary with environmental factors,
pollinator visits and microbial contamination. Pollination mutualisms
depend on the ability of insect and vertebrate pollinators to cope with and
benefit from the variation and diversity in nectar chemistry.
This article is part of the theme issue ‘Natural processes influencing
pollinator health: from chemistry to landscapes’.