Olfaction in the Anthropocene: NO3 negatively impacts floral scent and nocturnal pollination

There is growing concern about sensory pollutants impacting ecological
communities. Anthropogenically enhanced oxidants (O3 and NO3) rapidly
degrade floral scents, potentially reducing pollinator attraction to
flowers. However, the physiological and behavioral impacts on pollinators
and plant fitness are unknown. Using a nocturnal flower-moth system, we
find that atmospheric concentrations of NO3, but not O3, eliminate flower
visitation by moths, and it is the reaction of NO3 to a subset of
monoterpenes that reduces the scent’s attractiveness. Global atmospheric
models of floral scent oxidation reveal that pollinators in certain urban
areas may have a reduced ability to perceive and navigate to flowers.
These results illustrate the impact of anthropogenic pollutants on an
animal’s olfactory ability and indicate that such pollutants may be
critical regulators of global pollination.