The dwindling bee population could be related to colony stress and diesel exhaust.
New research suggests extended periods of stress can result in colony failure, a Royal Holloway University press release reported.
The study found that when bees were exposed to low levels of chemicals called neonicotinoid pesticides their behavior changed.
The pesticides are not directly lethal to bees, but once the buzzing insects are exposed they stop "working properly within the colony." The team found the amount of pesticides bees are exposed to in the field is enough to cause individuals to stop performing vital tasks, which can result in colony failure.
The finding could help researchers pinpoint what has caused the steady decline in bee populations over the past several years.
"One in three mouthfuls of our food [depends] on bee pollination," lead author, Dr. John Bryden from the School of Biological Sciences at Royal Holloway, said. "By understanding the complex way in which colonies fail and die, we've made a crucial step in being able to link bee declines to pesticides and other factors such as habitat loss and disease which can all contribute to colony failure."
"Exposing bees to pesticides is a bit like adding more and more weight on someone's shoulders. A person can keep walking normally under a bit of weight, but when it gets too much - they collapse. Similarly, bee colonies can keep growing when bees aren't too stressed, but if stress levels get too high the colony will eventually fail," he said.
The team hopes these findings will help influence future decisions when it comes to environmental issues such as pesticide use.
"Pesticides can have a detrimental effect on bees at levels used in the field," co-author Dr. Nigel Raine, said. "Our research will provide important evidence for policymakers. The way we test pesticides, the way we assess their impact on bees, and the way we manage pesticides can all be improved."
Exhaust from diesel fuel has also been linked to disappearing bees. A University of Southampton study found that the fumes could neutralize chemicals that help make up floral scents. The presence of the pollution could keep bees from sniffing out nearby flowers.
"Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new [odors]. NOx gases represent some of the most reactive gases produced from diesel combustion and other fossil fuels, but the emissions limits for nitrogen dioxide are regularly exceeded, especially in urban areas. Our results suggest that that diesel exhaust pollution alters the components of a synthetic floral [odor] blend, which affects the honeybee's recognition of the [odor]. This could have serious detrimental effects on the number of honeybee colonies and pollination activity," Tracy Newman, a neuroscientist at the University of Southampton, said.
