Pollution prevents flies from mating might look like a good news. After all, their intermittent buzz, the tickling they cause us when they land on any part of the body or, worse still, the pathogens they can carry to the food that they are so attracted to are elements that we would surely prefer not to deal with.
However, in addition to buzzing and bothering, flies play a key role in pest control, decomposing vegetation or droppings by rotting, and pollinating flowers, among other functions. Without them, the balance in the ecological interactions of the entire planet would be lost, and the consequences would be palpable for all organismsincluding humans.
For these reasons, the results of a study published yesterday in Nature Communications they are not encouraging. The work confirms that air pollution interferes with the mating of flies, specifically fruit flies or Drosophila melanogaster.
communication by pheromones
In previous research, the scientific team had already found that ozone and nitrogen oxide pollution degrade the smell of flowers and interfere with their pollination by insects such as moths. The sexual communication of fliesas well as many other insects, is established mainly through pheromoneswhich have a chemical component (a carbon-carbon double bond) that is especially sensitive to ozone.
Thus, the scientific team wondered if air pollution could also affect the ability of insects to find a mate. In fruit flies, the pheromones emitted by males attract females and repel other males. Also, during copulation, these pheromones are transmitted from males to females, so a newly copulated female is not attractive to other males for a few hours.
To find out if ozone was capable of altering this process, the team exposed a group of male flies to a slightly elevated concentration of ozone, and measured the pheromones they emitted. The results were clear: two hours of ozone significantly reduced pheromone levels compared to a control group in which the flies were only exposed to ambient air.
Males that attract males
In addition, the team found that the reduction in pheromones affected the attraction between males and females: females were not as attracted to males in the group exposed to ozone. But, in addition, the reduction in the level of pheromones caused the males to no longer repel each other, and the males in the ozone-exposed group had become yet another sexual target for other males.
These same results apply to eight other fly species Drosophila that also base their sexual courtship on pheromones, according to the same study. However, the species d.suzukiidevoid of pheromones and guided by visual stimuli, was not affected by ozone levels.
Flies and their pheromones have evolved over millions of years, while the concentration of pollutants in the air has increased dramatically in a matter of decades. Therefore it is very unlikelyAccording to the research team, that these insects are able to adapt to a reduction in pheromones as revealed by this study. If that were the case, fly populations could decrease significantly, thus altering the ecological balance of their ecosystems.
beyond the flies
Now the team has set out to study the effect of ozone on other insect species. The pheromones of most insect species have the same chemical characteristics as those of flies, For this reason, it is expected that the altered behavior of flies is also reflected in other insects..
In some of them, such as ants, bees or wasps, chemical communication goes beyond mating, and they use pheromones to identify members of their colony. The next investigations will be oriented to find out if contamination affects the social structure of ants when they return from foraging or that of the bees in their hives. The study provides one more explanation for why insect populations are in decline globally, which complements the use of insecticides and the removal of habitats.
In addition, the research team maintains that the effects of this altered behavior could be devastating for the environment and for the climate. Environmental contamination could also affect the reproduction of pollinating insects, such as bees or butterflies, a particularly worrying fact given that 80% of our crops rely on insect pollination to thrive. Bill Hansson, director of the Max Planck Institute for Chemical Ecology, concludes: “The only solution to this dilemma is to immediately reduce pollutants in the atmosphere.”
DON’T GET IT:
- There have been many attempts to prove that pheromones also play a role in humans, and numerous brands sell perfumes that are supposed to promote sexual attraction. However, the available scientific evidence is, to say the least, dubious. Studies that have exposed participants to pheromone candidates (such as androstadienone, found in the semen and sweat of men, or stratetraenol, found in the urine of women) have not found significant differences in sexual attraction. .