One of the reasons given for the substantial decline of pollinators in many parts of the world - along with habitat loss, disease and insecticides - is environmental pollution. Now, researchers have discovered that diesel exhaust could be contributing to this because of the effect it has on flower odors.
In the Journal of Chemical Ecology, a study from the Universities of Southampton and Reading, both in the UK, reports how of the 11 most common single compounds in flower scents, five can be so chemically degraded by toxic nitrous oxide (NOx) gas from diesel exhaust that honey bees no longer recognize them.
We already know that NOx is harmful to humans, and there is also evidence that it can confuse bees’ sense of smell, which they rely on to locate food; they eat nectar and pollen from flowers.
Lead author Dr. Robbie Girling, a lecturer in agro-ecology and sustainable agriculture at Reading, says:
“People rely on bees and pollinating insects for a large proportion of our food, yet humans have paid the bees back with habitat destruction, insecticides, climate change and air pollution.”
According to a United Nations report published in 2011, of the 100 crop species that provide 90% of the world’s food, over 70 are pollinated by bees.
In 2000, the value of crops pollinated by bees was estimated at $14.6 billion in the US alone.