The differential impact of air pollution on insect chemical communication.

Abstract

Airborne chemical communication is vital for insect survival and reproduction, yet its vulnerability to anthropogenic air pollution is poorly understood. We investigate how the physicochemical properties of alarm and sex pheromones influence their atmospheric persistence under pristine and polluted conditions. Using a volatility basis set framework, we show that alarm pheromones-small, volatile, and chemically simple-remain in the gas phase with lifetimes largely unaffected by pollution. In contrast, sex pheromones are larger, less volatile, and more reactive, suffering dramatic reductions in lifetime and spatial range under polluted nocturnal conditions. A key driver of this decline is gas-to-aerosol partitioning, which can remove pheromones from the gas phase faster than chemical degradation. While this may impair detection, aerosol-bound pheromones could be protected from oxidation, potentially extending their lifetime. These findings reveal that air pollution disproportionately disrupts sex pheromone signalling, highlighting a nuanced pathway by which ecological communication is impaired.