New research suggests that diesel fuel emissions may be interfering with how bees find flowers, something that in turn could contribute to Colony Collapse Disorder and threaten global food security.
It has long been understood that honeybees use the odor flowers give off in order to forage. Now, research conducted by the University of Southampton appears to show that diesel exhaust fumes actually change the profile of plant odors so much so that honeybees no longer recognize them.
Published in Scientific Reports this month, the research showed how the eight chemicals that are found in the odor of oil rapeseed flowers, which the test bees had been trained to recognize, were reduced or completely disappeared when diesel exhaust fumes were introduced — so much so that the bees could no longer detect them.
Similarly, when the odors were mixed with NOx gases, of which diesel cars emit more than even petrol cars, the same effect was observed.
The potential issues this might cause could at first seem small but on a global scale could have a disturbing impact: if bees are unable to sense the plants they use for foraging, their pollination efficiency is reduced, which ultimately has implications for food security.
Co-lead research Professor Guy Poppy, an ecologist at the University, puts this in real terms for us: “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 odor 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.”
Diesel pollution is one among several problems or “stressors” that global bee populations are currently facing. These issues may be leading to radically reduced bee numbers as a result of what is known as Colony Collapse Disorder, where hives are abandoned and colonies die off. A range of studies have provided various reasons for this, key among them being infestations of the varroa mite, cellphones and the widespread use of pesticides.
Until now, however, diesel exhausts have not been identified as a serious factor. The researchers argue, though, that when this is teemed with the other stressors noted above, the bees could be in big trouble:
“This is the first clear research looking at the environment in which honeybees work,” co-lead researcher Dr. Tracey Newman is quoted as saying. “Our results suggest that diesel exhaust pollution alters the components of a synthetic floral odor blend, which affects the honeybee’s recognition of the odor. 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.”
The particular emphasis on diesel adds to other research that this once supposed “greener” alternative to petrol is really no alternative at all. Animal studies have shown that diesel exposure may increase obesity by interfering with the body’s hormonal balance, may raise cancer and wider mortality rates and can cause breathing problems for those with asthma.
So in fact, it isn’t just the honeybees that need us to act on this problem: our own health and that of future generations may depend on it too.
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