A new study published on March 14 in the journal Nature Communications warns that air pollution disrupts the romantic lives of fruit flies. After inhaling poisonous gas, male common fruit flies had difficulty distinguishing their female counterparts, driving them to pursue another male.
Although some research has hinted at bisexuality among fruit flies, the most recent findings imply it has more to do with ozone pollution. Even little exposure to O3 was sufficient to change the chemical composition of pheromones, which flies use to locate and attract partners. Rising levels of air pollution from automobiles, power plants, and industrial boilers might prevent the reproduction of common fruit flies, leading to a precipitous drop in the insect population.
Chemical ecologists placed fifty male flies in a tube and subjected them to 100 parts per billion (ppb) of ozone for two hours; worldwide ozone levels range from 12 to 67 ppb. After two hours, the level of the pheromone cis-Vaccenyl Acetate (cVA) in molecules involved in reproductive activity decreased in fruit flies.
Upon deeper inspection, it was discovered that ozone appears to have altered the chemical structure of pheromones. Markus Knaden, group head for insect behavior at the Max Planck Institute for Chemical Ecology in Germany and author of the study, notes that the majority of insect pheromones contain carbon double bonds. When a molecule has carbon double bonds, it becomes extremely vulnerable to ozone or nitric oxide oxidation and begins to split. The hypothesis is consistent with their results of large levels of the liquid heptanal in the flies, which is a byproduct of the breakdown of cVA.
Could changed pheromones impact a man’s ability to locate a partner? It seems so. In a separate experiment, male fruit flies were exposed to ozone concentrations ranging from 50 to 200 ppb for 30 minutes before being put with female fruit flies. While males in both groups spent little time courting females, ozone-exposed fruit flies had a more difficult time finding a partner.
“The guy promotes himself through pheromones. “The more offspring he produces, the more desirable he is to females,” explains Knaden. The absence of the chemical aphrodisiac rendered ozone-exposed men less alluring to women, who took nearly twice as long to choose from the tainted bachelors as they did from the clean ones.
Not only does ozone pollution hinder males’ capacity to attract female attention, but it also hinders their ability to distinguish other individuals. Knaden says his team anticipated that the changed pheromones would impact male fruit flies’ capacity to discern between males and females, but they did not anticipate that males would leap on one other. “Initially, it was a pretty amusing sight to witness extremely lengthy chains of males wooing one another,” he explains. With the changed pheromones, “the male basically jumps on everything that is little and moves a little bit like a fly”
James Ryalls, a research fellow at the Center for Agri-environmental Research at the University of Reading in England who is unaffiliated with the study, says, “It’s great to see this work getting underway, as very little is known about how air pollution interferes with insect sex pheromone signaling.” The study reveals how disruptive air pollution may be to insect communication, with possible ecological consequences such as a reduction in biodiversity.
At first appearance, eliminating the pests that infest your bananas and melons may seem like a smart idea. Yet, Ryalls cautions that these agricultural pests have a significant impact on the global ecology. Fruit flies help digest decaying fruit, therefore releasing nutrients for use by plants, bacteria, and fungus. They also provide as a source of nutrition for birds and spiders. In addition, they are a frequent insect model used in scientific research and have led to innumerable discoveries in brain and genetics.
Not just fruit flies are negatively affected by air pollution. Knaden has seen unsafe ozone levels impacting floral volatile chemicals, which pollinators utilize as signals. His 2020 study revealed that moths were less attracted to the floral smells of gas-exposed plants, resulting in decreased pollination.
According to Knaden, the fall of insects was previously attributed to pesticides and habitat destruction. “It appears there are more knobs to adjust, air pollution being one of them.”