Flowers produce and emit fragrances that play crucial roles in plant-insect interactions. Oxidants such as ozone, hydroxyl radical, and nitrate radical can deleteriously impact plant-insect interactions as they readily react with floral odors and change the chemical composition of the original scents. In polluted air masses, reactions chemically destroy floral odor plumes and reduce the distance that scents travel from their sources. Experimental and theoretical results will be presented to evaluate the general hypothesis that enhanced air pollutants deleteriously impact pollinators and plant communities due to reduced quality and quantity of floral odor mixtures.
In one study, an insect failed to detect its host plant when ozone mixing ratios exceed 80 parts per billion (ppbv) because chemical reactions altered the quality and the quantity of scents. In polluted environments, insects may not recognize the plant-emitted scents because the proportion of each chemical species in the plume is modified by chemical reactions. Results from a three-dimensional numerical model indicate that insect foraging times significantly increase in polluted conditions due to considerable scent plume degradation of the floral scents. Results also indicate that increased levels of air pollutants could perniciously contribute to the observed declines in the insect pollinators and reduced pollination efficiency done by insect pollinators.