Project to study changing bee habits
23 November 2009
A new research project is to look into why bumblebees are becoming increasingly active in winter, foregoing their usual hibernation in favour of the delights of winter-flowering trees and shrubs planted by gardeners.
The project, funded by the Leverhulme Trust and carried out by scientists from Queen Mary, University of London and the Bees, Wasps and Ants Recording Society (BWARS), is investigating a number of theories. Climate change and hybridisation with foreign bumblebees imported to pollinate polytunnel crops are thought to be possible reasons, as well as the popularity of gardening for wildlife.
The phenomenon of winter bumblebees was first recorded by wildlife gardener and ecologist Marc Carlton, who began keeping notes about the bees visiting his London garden over winter in 2006. He found bumblebees out and active on plants such as winter honeysuckle during January – even after snowfall.
“Many insects appear to be extending their distribution due to the changing climate, but this is one of the first examples of them apparently changing their behaviour,” says Marc.
His data was backed up by BWARS members who reported winter bee activity at more than 600 sites last winter, mainly in urban and suburban locations in the south of England although some were recorded as far north as Hull.
Cultivars of Mahonia were most popular with winter bees, though they also visited shrubby honeysuckles, winter-flowering Clematis cirrhosa and early-flowering spring bulbs such as snowdrops and crocus.
However, almost all the bees were of just one species, the buff-tailed bumblebee (Bombus terrestris). Marc warns this could be bad news for other bumblebee species which don't venture out in winter and could find all their breeding sites already taken by the time they wake up in spring.
“My personal view is that Bombus terrestris will become a bit like the urban fox, doing very well in towns and cities in comparison to its competitors because it can take advantage of gardens and winter shrubs,” says Marc.
BWARS is now collecting information about winter bumblebee activity this winter. If you'd like to help by contributing data on winter bees in your garden, you can find out more by visiting their website.