Since compounds with carbon double bonds are particularly sensitive to ozone degradation, and almost all insect sex pheromones carry such double bonds, we wondered whether air pollution also affects how well insect females and males find and identify each other during mating', says Markus Knaden, who heads the Odor-guided Behavior Group in the Department of Evolutionary Neuroethology and is a lead author of the study (see also press release, September 4. 'We already knew that environmental pollutants such as ozone and nitric oxide degrade floral scents, making flowers less attractive to their pollinators. Such double bonds are known to be easily destroyed by ozone.

Most insect pheromones are odor molecules containing carbon-carbon double bonds. Even the smallest differences, such as those observed in the formation of new species, ensure that mating no longer takes place, because males and females only find each other through the unmistakable odor of their conspecifics. Sex pheromones are distinctive to males and females of a species.

Insect sexual communication relies to a significant extent on pheromones, chemical attractants that specifically allow males and females of a species to mate.

view moreĬredit: Benjamin Fabian, Max Planck Institute for Chemical Ecology

Male flies exhibited unusual courting behavior towards other males that had been exposed to increased ozone levels as they are nowadays often found in cities in the summer. Image: Courting chain of four male Drosophila flies.

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