A possible link between pollution found in diesel fumes and the global collapse of honey bee colonies is to be investigated.
Researchers from the University of Southampton believe nanoparticles emitted from diesel engines could be affecting bees' brains and damaging their in-built navigation skills.
They believe this may stop worker bees finding their way back to the hive.
There is also a theory that diesel fumes mop up flower smells in the atmosphere, making it difficult for the insects to find food.
Ecologist professor Guy Poppy and neuroscientist Dr Tracey Newman think nanoparticles are one of a number of stress factors which could lead to a tipping point in bee health, which in turn could contribute to bee-colony collapse.
They will now take part in a three-year, £156,000 study to find out more.
"Diesel road traffic is increasing in the UK and research from the US has shown that nanoparticles found in its fumes can be detrimental to the brains of animals when they are exposed to large doses," explained Mr Poppy
"We want to find out if bees are affected in the same way, and answer the question of why bees aren't finding their way back to the hive when they leave to find food."
Bees are estimated to contribute billions to the world's economy, £430 million a year to the UK alone, by pollinating crops, producing honey and supporting employment, the researchers said.
Yet winter losses of bees have led to a drop of tens of thousands of beehives year on year since 2007. The US has seen a 35% unexplained drop in the number of hives in 2007, 2008 and 2009, they added.