Car exhaust keeps moths from smelling the roses

Floris van Breugal, Art in Nature Photography

Car exhaust keeps moths from smelling the roses

The acrid smell of car exhaust may seem a far cry from the fragrance of flowers, but both elicit similar responses in the brains of moths, throwing them off in their search for flower nectar. Researchers placed the Manduca sexta moth in a wind tunnel and exposed it to the odor of its favored flower, the sacred datura; they also pumped in other smells that the American insect is likely to encounter in its flight. Sometimes, the confounding smell came from the creosote bush in which the datura often grows. Other times, the smell was from compounds in fuel emissions. In both cases, the moth found it harder to zero in on the flower odor, the researchers report online today in Science. The reason the moth is confused by such disparate smells could be the benzene ring, which is at the heart of several compounds that make up natural and artificial odors. Moths may not be the only victims of such distractions in their search for food. Bees, which pollinate a lot more in urban environments, could also find vehicle emissions confusing, says Jeffrey Riffell, a biologist at the University of Washington, Seattle, and the lead author of the study. The finding is surprising, the researchers say, because moths, like dogs, have a strong sense of smell that is several thousand times sharper than ours. It is also troubling because each minute wasted in search of food eats up valuable energy for these pollinators.

Posted in Plants & Animals