UK: New research has found that being infected with Nosema ceranae, a common parasite, significantly affects honeybees’ chances of returning to the hive after foraging.
The scientists, from Rothamsted Research, found that 35% of bees infected with the parasite never returned, while among healthy foragers the figure was less than 10%.
Dr Stephan Wolf, who led the study, said: “This is obviously bad news for bees infected with the parasite. But in some ways it’s surprising that so many infected bees did so well.
“We’re talking about heavily infested animals, but we couldn’t find any difference in their flight patterns – they didn’t seem to get lost or confused. It seems some of them were just too exhausted to make it back to the nest. This raises important questions about why some infected bees are able to function in exactly the same way as healthy bees, while others are unable to cope.”
Nosema parasite spores invade cells in the gut, drawing energy for themselves while damaging the bees’ ability to absorb food.
The only available treatment for Nosema infections, a fungicide called fumagillin, is banned in the European Union over environmental safety concerns. And there is a debate among researchers about its effectiveness against the parasites.