As we spend summer after summer swatting them away, it is difficult to conceive that they will ever be eradicated.
Air pollution has made many fly species’ mating cues “dysfunctional,” according to a study.
In the presence of ozone contaminants, which ‘dramatically corrupt’ their reproductive behavior, flies struggle to feel attracted to potential mates, according to disturbing new research.
Fly numbers are declining worldwide, and 80% of the world’s crops depend on them.
Ozone-exposed flies showed “unusual courtship behavior,” with males preferring men and unable to distinguish between sexes.
Because the disintegration of carbon double bonds, and thus pheromones, by oxidation, is not rocket science in chemistry, researchers Nanji Jiang and Markus Knaden from the Max Planck Institute for Chemical Ecology knew that elevated ozone levels could affect insect mating systems.
However, we were astonished that even modestly elevated ozone concentrations had such a profound impact on fly behavior.
In addition to causing asthma attacks, ozone gas can cause inflammation of the eyes, sinuses, respiratory tract, and throat.
Although it was present in the lower atmosphere during the preindustrial era, experts estimate that concentrations were as low as 10 parts per billion (ppb) compared to the current concentrations of 40 ppb.
According to a distinct JGR Atmospheres study, ozone levels in Mexico have recently risen to 210 ppb due to a combination of climate change and the continued emission of nitrogen oxides.
As part of the investigation, flies were placed in an ‘ozone exposure system’ that simulated summertime urban air pollution levels.
When flies were exposed to 100ppb of the pollutant for just two hours, the levels of chemical attractants decreased significantly.
Males affected by ozone were also observed forming “long courtship chains” that were deemed to be quite perplexing.
Other species of fly that rely on visual cues rather than pheromones for mating did not alter their behavior.
Drs. Jiang and Knaden added, ‘We could explain why males began courting each other after a brief exposure to ozone. As they were unable to differentiate ozonated males from females.
However, we had not previously considered this.
We were therefore quite perplexed by the behavior of the ozone-exposed males, who formed long courtship chains.
Bill Hansson, co-founder of the Max Planck Center for the Next Generation of Insect Chemical Ecology, deemed it ‘unlikely’ that flies would be able to adapt to swiftly increasing air pollution.
Over millions of years, insects and their pheromones have evolved. Since industrialization, the concentration of air pollutants has only increased dramatically.
