Air pollution is not only affecting birds and marine life, but it is also disrupting the sense of smell in animals that rely on it for survival. A recent study published in the journal Science reveals how air pollution is altering the scent of flowers and impacting nocturnal pollinators.
While light and noise pollution have been widely studied, the detrimental effects of air pollution on wildlife that depend on scent have been largely overlooked. The research conducted by a team of scientists from the University of Washington sheds light on this little-known issue.
The study focused on a type of insect called a hawk moth, which uses its antennae to detect the scent of flowers from over a kilometer away. These moths beat their wings rapidly to hover in midair and extract nectar from flowers, often being mistaken for hummingbirds. One of their favorite flowers is the pale evening primrose, a ghostly white flower that blooms at night.
To understand the impact of air pollution on these nocturnal pollinators, the researchers collected samples of the pale evening primrose’s scent in the field and isolated the individual chemicals that make up its bouquet. They found that certain scent chemicals that attract moths degrade in the presence of NO3, a potent pollutant formed from car emissions, coal plants, and other industrial sources. NO3 accumulates in the air at night as it is destroyed by sunlight.
In lab experiments, two moth species, the white-lined sphinx, and the tobacco hawk moth, struggled to fly towards the primrose scent when exposed to NO3 levels typically found in cities at night. When the researchers treated both real and artificial flowers emitting the primrose scent with NO3 in the field, wild moth visitation decreased by about 70 percent.
“The flowers only bloom once per night,” said Jeff Riffell, a biologist from the University of Washington. “Without their pollinators, there can be a huge change in the plant community.”
The findings of this study are the first to highlight the effects of nighttime pollution on pollinators. Robbie Girling, a chemical ecologist at the University of Southern Queensland, described the results as “exciting and a bit scary.” In his own experiments, Girling discovered that exposing bees and other daytime pollinators to diesel exhaust and ozone reduced their visits to flowers.
While the study focused on a limited number of species, Girling believes that air pollution could have widespread impacts on ecosystems worldwide. However, he cautions that more research is needed to fully understand the extent of this issue.
As humans, we often overlook the importance of scent in the animal kingdom. We rely heavily on our visual and auditory senses, but for many animals, scent is their primary means of communication and navigation. The disruption of their sense of smell due to air pollution could have far-reaching consequences for the delicate balance of ecosystems.
This study serves as a reminder that our actions have unintended consequences on the natural world. As we continue to grapple with the effects of climate change and pollution, it is crucial to consider the impact on all living beings, including those who rely on their sense of smell to survive. By addressing air pollution and its effects on wildlife, we can take steps towards preserving the intricate web of life on our planet.
