Where do bumblebees go in winter?
Guest Blog by Darryl Cox - Senior Science and Policy Officer, Bumblebee Conservation Trust.
The Colony ends for the year
As autumn creeps into winter, there are notably fewer flowers around and also fewer bumblebees, if any. Sad as it may seem, this is the natural boom and bust life-cycle of flowers and bees.
By now, most bumblebee colonies have finished for the year. All of the workers and males die off naturally, having done their bit, as do the original queens that established the colony.
The future of the colony now rests with the new queens and these future heads of state currently find themselves tucked up in hibernation, under the soil and deep amongst the leaf-litter, waiting for the cold weather to pass and for spring to commence.
Their safe passage through winter and successful establishment of a colony next year are key to the future of not only their offspring, but the vast array of plants and animals (including us humans), which depend on their pollination services.
What to do if you discover a hibernating queen
Should you happen to come across a hibernating queen while digging in the garden or repotting an old plant, the best thing to do is cover her back up loosely with the soil you found her in and avoid disturbing that area again until she emerges in spring.
White-tail bumblebee (Bombus lucorum) found hibernating in a plant pot.
If however, you disturb a queen in late winter and she seems quite lively, buzzing to warm herself up, you could try offering her a mix of 50/50 sugar and water to give her a boost and help her on her way to finding food and shelter.
Please note – providing bees with sugar water is only ever a temporary fix and should never become their main diet (that would be like a human swapping three meals a day for three cans of fizzy juice). Nectar and pollen from flowers contain the nutrients bees need to thrive, as well as the energy they require to survive.
Why are some bees braving winter?
Occasionally, we do see some bumblebees remaining active during the winter months, although exactly why this is happening remains a bit of a mystery. It could potentially be an adaption by some species to climate change, particularly as it is usually in the warmer, southern half of the UK that these winter-active bumblebees are most regularly spotted.
Another contributing factor could be thanks to the available range of exotic non-native garden plants like Mahonias and Winter-flowering honeysuckles. These plants will happily flower right into the depths of winter, at a time when our native plants tend to retreat into dormancy. It seems like some bumblebees are beginning to adapt and take advantage of these relatively newly introduced food resources appearing in gardens across the UK.
Buff-tail bumblebee foraging on Mahonia in winter
If you do happen to see any bumblebees foraging over the winter months, it would be great if you could try to take a photo and send it in to the Bees Wasps and Ants Recording Society (BWARS), who are monitoring this interesting phenomenon. For useful tips on photographing bumblebees for identification purposes see: www.bumblebeeconservation.org/using-photographs-for-id.
For more information on bumblebees and how you can help them please visit www.bumblebeeconservation.org.