When bees set out to look for nectar, they use their sense of smell to locate food sources thousands of feet away from their hives. In 2006, researchers studying the honey bee genome found that honey bees have 170 different odor receptors that are able to distinguish between the scent profiles of different types of flowers. This remarkably sensitive faculty of smell is critical to the bees’ ability to navigate effectively and find reliable food sources.
Now, a group of scientists at the University of Pennsylvania is raising concerns about the disruptive effect airborne pollutants can have on honey bees’ sense of smell.
In a study published in Atmospheric Environment, the scientists found that “even moderate air pollutant levels” can change the chemical composition of flower scents, making it much more difficult for the bees to sniff out their food. Pollutants such as ozone, nitrate radical and hydroxyl radical were especially disruptive to the bees’ ability to find flowers.
To measure the effects of airborne pollutants on floral scents, the scientists ran 90,000 computer simulations of various wind conditions and pollutant concentrations. They found that ozone concentrations as low as 60 parts per billion can change the chemical composition of floral scents enough to make it harder for bees to find food.
“We found that when we confused the bees’ environment by modifying the gases present in the atmosphere, they spent more time foraging and would bring back less food, which could affect their colonies,” said Jose D. Fuentes, professor of meteorology and atmosphere science at Penn State.
In the study’s abstract, the scientists note that “the increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.”
With honey bee populations already struggling to survive as a result of habitat loss and disease, this interference from pollutants could have an even more profound effect on the bees’ ability to collect food. Hopefully – armed with this new knowledge about how pollutants interfere with bees’ sense of smell – scientists and beekeepers can take steps to limit pollution around bee hives and make it easier for bees to find their food and pollinate crops.