‘Trojan hives’ carry parasites to native bees

Many bumblebee colonies imported into the UK for crop pollination are infested with parasites, a study in the Journal of Applied Ecology suggests.

More than a million bumblebee colonies are shipped around the world each year. When the bees alight on the same flowers as native insects, they can transmit parasites. Some countries now require imported colonies to be tested for diseases, and companies “often claim that their colonies are free of parasites,” the study authors write.

Not so, the team found. The researchers tested 48 colonies imported into the UK in 2011 and 2012 and found parasites in 77 percent of them. They also investigated whether the parasites could infect other insects. The survival of bumblebees exposed to feces from the diseased colonies dropped from 61 to 44 percent, and honeybee survival dropped from 70 to 40 percent.

The results “are genuinely alarming,” the researchers write. They urge countries to adopt stricter checks on colonies “to reduce the pathogen spillover threat from commercially produced bumblebees.” Roberta Kwok | 18 July 2013

Source: Graystock, P. et al. 2013. The Trojan hives: pollinator pathogens, imported and distributed in bumblebee colonies. Journal of Applied Ecology doi: 10.1111/1365-2664.12134.

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