Increased ozone levels disrupt insect sexual communication

Abstract

Insect sexual communication often relies upon sex pheromones1-3. Most insect pheromones, however, contain carbon-carbon double bonds and potentially degrade by oxidation4. Here, we show that already frequently reported increased levels of Anthropocenic ozone can oxidize all described male-specific pheromones of Drosophila melanogaster5-7, resulting in reduced amounts of e.g. cis-Vaccenyl Acetate and (Z)-7-Tricosene. At the same time female acceptance of ozone-exposed males is significantly delayed. Interestingly, groups of ozonized males also exhibit unnaturally high levels of male-male courtship behavior. When repeating similar experiments with nine other drosophilid species, we observe pheromone degradation and/or corrupted sex recognition in eight of them. Our data suggest that Anthropocenic levels of ozone can oxidize double bonds in a variety of insect pheromones extensively, thereby leading to deviations in sexual recognition.