Common diesel exhaust pollution notably limits the sensory abilities of honeybees, new research from the University of Southampton has found, possibly greatly limiting bees’ ability to forage effectively. Many of the common air pollutants found within diesel exhaust appear to greatly limit the honeybees’ ability to recognize floral scents — scents which they rely on when foraging, both for locating food sources and for identifying/differentiating them.
The effect appears to be the result of the diesel fumes “changing the profile of floral odors.” The lead researchers, Dr Tracey Newman and Professor Guy Poppy, think that these changes “may affect honeybees’ foraging efficiency and, ultimately, could affect pollination and thus global food security.”
The University of Southampton provides details on the research:
The study mixed eight chemicals found in the odour of oil rapeseed flowers with clean air and with air containing diesel exhaust. Six of the eight chemicals reduced (in volume) when mixed with the diesel exhaust air and two of them disappeared completely within a minute, meaning the profile of the chemical mix had completely changed. The odour that was mixed with the clean air was unaffected.
Furthermore, when the researchers used the same process with NOx gases (nitric oxide and nitrogen dioxide), which is found in diesel exhaust, they saw the same outcome, suggesting that NOx was a key facilitator in how and why the odour’s profile was altered. The changed chemical mix was then shown to honeybees, which could not recognise it.
Dr Tracey Newman, who’s also a neuroscientist at the University of Southampton, states: “Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new odours. 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 diesel exhaust pollution alters the components of a synthetic floral odour blend, which affects the honeybee’s recognition of the odour. This could have serious detrimental effects on the number of honeybee colonies and pollination activity.”
Professor Guy Poppy, who’s also an ecologist at the University of Southampton, explains further: “Honeybee pollination can significantly increase the yield of crops and they are vital to the world’s economy — £430 million a year to the UK alone. However to forage effectively they need to be able to learn and recognize the plants. The results indicate that NOx gases — particularly nitrogen dioxide — may be capable of disrupting the odour recognition process that honeybees rely on for locating floral food resources. Honeybees use the whole range of chemicals found in a floral blend to discriminate between different blends, and the results suggest that some chemicals in a blend may be more important than others.”
The new research was published in the journal Scientific Reports.