Research from the Max Planck Institute for Chemical Ecology shows that elevated ground‑level ozone oxidizes fly pheromones, impairing mate recognition. Damaged male pheromones make males less attractive to females and increase male‑male courtship in several Drosophila species. The findings raise ecological concerns because disrupted pollinator reproduction could affect plant pollination and crop yields. Reducing emissions and supporting local air‑quality advocacy are practical steps to limit ground‑level ozone.
Ozone Pollution Breaks Down Fly Pheromones — And Triggers Same‑Sex Courtship, Study Finds
New laboratory research from the Max Planck Institute for Chemical Ecology shows that elevated ground‑level ozone chemically degrades fly pheromones, disrupting mate recognition and changing courtship behaviour in several Drosophila species.
How Ozone Interferes With Mating Signals
The study found that exposure to modestly increased ozone concentrations oxidizes the chemical compounds that flies use as pheromonal signals. When these cues are altered, males and females have difficulty recognising one another. In particular, altered male pheromones become less attractive to females and — unexpectedly — more likely to draw courtship from other males, producing a measurable rise in same‑sex courtship among tested Drosophila species.
"We were shocked that even slightly elevated ozone concentrations had such strong effects on fly behavior," said Nanji Jiang and Markus Knaden of the Max Planck Institute. "We had originally planned to study male‑female interactions. We could explain that males began courting one another after a brief ozone exposure because ozonated males were no longer distinguishable from females. However, we had not thought about this before."
Why Ground‑Level Ozone Matters
Ozone high in the stratosphere shields Earth from harmful ultraviolet radiation, but ground‑level ozone is a pollutant formed when nitrogen oxides and volatile organic compounds from vehicles, industry and other sources react with sunlight. According to the U.S. Environmental Protection Agency, ground‑level ozone is not emitted directly but forms through these chemical reactions and is associated with respiratory harms, crop damage and ecosystem stress.
Broader Ecological Concerns
Flies, including many Drosophila species, play roles as pollinators for wild plants and some crops. The researchers caution that if air pollution consistently degrades pheromonal signals, it could reduce reproductive success and ultimately affect pollinator populations. Any decline in pollination services has the potential to influence plant reproduction and crop yields — though more field studies are needed to quantify real‑world impacts beyond laboratory conditions.
What Can Be Done
The study reinforces how human activities ripple through ecosystems. Standard strategies to curb ground‑level ozone production include reducing fossil fuel combustion, transitioning to electric vehicles, expanding renewable energy like solar, and cutting waste and unnecessary plastic use. Community advocacy and education groups such as Moms Clean Air Force also work locally to reduce air pollution and protect public and environmental health.
Takeaway: Even modest increases in ground‑level ozone can chemically disrupt insect chemical communication, altering behaviour and raising concerns about wider ecological consequences.
