Saturday, October 5, 2013

No one likes diesel fumes! Not even bees!

from Reuters news agency:

Exhaust confuses bees, study finds

Diesel fumes mask scent of flowers


— Exposure to pollution from diesel ex­haust fumes can disrupt honeybees’ ability to recog­nize the smells of flowers and could in the future af­fect pollination and global food security, researchers said on Thursday.

In a study published in the nature journal Scientif­ic Reports, scientists from Britain’s University of Southampton found that the fumes change the pro­file of the floral odors that attract bees to forage from one flower to the next.

“This could have serious detrimental effects on the number of honeybee colo­nies and pollination activ­ity,” said Tracey Newman, a neuroscientist who worked on the study.

Bees are important polli­nators of flowering plants, including many fruit and vegetable crops.

A 2011 U.N. report esti­mated that bees and other pollinators, such as butter­flies, beetles and birds, do work worth $203 billion a year to the human econo­my.

Bee populations have been declining steadily in recent decades but there is scientific disagreement over what might be causing it. Much attention has been focused on whether a class of pesticides called neonico­tinoids may be the culprit.

A report from the Eu­ropean Food Safety Author­ity in January said three widely used neonicoti­noids, made mainly by Switzerland’s Syngenta and Germany’s Bayer, posed an acute risk to hon­eybees.

EU leaders voted in April to ban three of the world’s most widely used pesticides in this class for two years because of fears they could be linked to a plunge in the bee populations.

But the British govern­ment, which recommended abstaining in a previous EU vote in March, argues the science is inconclusive and advises caution in extrapo­lating results from labora­tory studies to real-life field conditions.

Guy Poppy, an ecology professor who worked with Newman, said that to be able to forage effectively honeybees need to be able to learn and recognize plants — a process their results showed could be disrupted by so-called NOx gases, par­ticularly nitrogen dioxide, found in diesel exhaust and other pollution.

For their study, the scien­tists took eight chemicals found in the odor of oil rape­seed flowers and mixed them in one experiment with clean air and in anoth­er with air containing die­sel exhaust.

Unrecognizable smell

They found that six of the eight chemicals reduced in volume when mixed with diesel fumes, and two disap­peared completely within a minute — meaning the pro­file of the chemical mix had changed. The odor mixed with clean air was unaffect­ed.

When the researchers used the same process with NOx gases — nitric oxide and nitrogen dioxide — found in diesel exhaust emissions, they saw the same results, suggesting NOx is key to how and why the odor’s profile was al­tered.

When the changed chem­ical mix was then shown to honeybees — which are known to use their sensi­tive sense of smell to forage for flowers — they could not recognize it.

Giles Budge of Britain’s Food and Environment Re­search Agency said New­ton’s study highlighted “a fresh issue to add to the many problems facing our insect pollinators.”

But he said that since the study was based in the lab­oratory, more research is needed to see if the problem is occurring in the wider environment.

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