It doesn’t take a scientist to tell you that car exhausts smells terrible. But it might take one to tell you that insects think so, too.
New research, published in the journal Science, looked at how the tobacco hornworn moth behaves when exposed to concentrations of car and truck exhaust similar to a typical urban environment. It found that the odor can be so noxious, that it can obscure the scent of sought-after flowers, causing delicate pollinators to waste precious energy trying to find the right bloom.
For the study, the moths were placed in a laboratory wind tunnel while the scent of the moths’ preferred food source, the flowers of the Sacred Datura plant, was piped in, along with different concentrations of the malodorous chemicals. The neuron pathways activated in the moths were tracked by electrode attached to the moth’s antennal lobe, where the moth processes what it smells with its antennae.
The vehicle exhaust decreased the moths’ ability to find flowers, and changed how the flower’s scent was processed by the moth’s brain
“Pollinators like bees, butterflies and moths use their sense of smell to locate flowers from long distances, but we found that scent from neighboring vegetation, and even pollutants given off from vehicle exhaust, can disrupt the moth’s behavior,” one of the study’s authors, University of Washington biology professor Jeffrey Riffell, said in a press release.
Pollinators across the U.S. are in trouble. While the plight of honeybees poisoned by pesticides has dominated the news recently, many key pollinator species are in decline. Bats are in trouble around the country as the mysterious and deadly fungal infection known as white-nose syndrome continues to spread from cave to cave. Many species of butterflies are also being adversely affected by climate change, which is throwing off the timing of migration, leaving them exposed to severe weather along their flight path. Certain types of butterflies and pollinating birds like hummingbirds are also affected by climate change, as a warming world has caused flowers to bloom earlier in the season, leading to a situation known as resource asynchrony, where birds and butterflies aren’t in the right place at the right time for the flowers they depend on.
“Beyond our work with moths, we’d also like to see if these volatiles affect other pollinators, like honeybees,” said Riffell. “Such work could provide insight into whether urban emissions affect pollinators in farms neighboring urban centers.”
On June 20, President Obama announced plans to create a special task force dedicated to helping the nation’s ailing pollinators. The team, led by Secretary of Agriculture Tom Vilsack and Environmental Protection Agency Administrator Gina McCarthy, will have 180 days to investigate current and future threats to birds, bees, butterflies and bats, and create a National Pollinator Health Strategy. According to the USDA, one-third of all food and beverages consumed in the U.S. are dependent on pollination.