Diesel exhaust rapidly degrades floral odours used by honeybees

Andrew Robbertz

Author: Tracey A. Newman
Published: October 3, 2013
http://www.nature.com/srep/2013/131003/srep02779/full/srep02779.html#ref14

Summary: Honeybees are our greatest managed pollinators on earth, yet every year large populations in colonies are dropping.  Air pollution is one of humanities greatest environmental impacts, however its effects on honeybees is still unknown. Honeybees have a sensitive sense of smell and the ability to learn and memorize new odors, allowing them to use floral odors to locate, identify and recognize the flowers from which they forage. There is a huge diversity to floral odors, therefore any small change in these blends could dramatically change the communication between each plant and its pollinator. Theoretical models predict that anthropogenic emissions are likely to reduce the detection distances of plant emitted odors available to pollinators. Despite advances in filtration technology, diesel exhaust remains a major environmental pollutant. In the study eight floral odors were exposed to diesel pollution. Within one minute of exposure the abundances of four of the chemicals were significantly lowered, with two components rendered undetectable. Honeybees were trained to recognize the full odor mix, but by removing the two chemicals rendered undetectable, significantly lowered the bees ability to recognize the odor mix. Furthermore, the study found that at environmentally relevant levels the mono-nitrogen oxide fraction of the exhaust gases was a key facilitator of the odor degradation. 

Connection: Although we don't know a lot about the health of honeybees, in the study,  a correlation between the diesel pollution and the senses of the honeybees. As part of our ecosystems unit we studied keystone species. In many ecosystems honeybees are a keystone species. They pollinate plants, which are later consumed and they are sometimes consumed themselves. The air pollution in many ecosystems is changing the odor mix of many of the plants and flowers that honeybees feed on. With the drop in populations of honeybees one could see the rest of the ecosystem slowly fall apart. Through this it is necessary that we continue to limit the amount of air pollution being produced so we can save the keystone species and prevent the collapse of these ecosystems.