Bumblebee Aware October 2021 by Adrian Doble

  • When did you last hear or see a bumblebee?  Most UK species have disappeared from our gardens by now, either because they were members of this year’s brood of workers and males who have died, or because they are new queens who have found a secure place to hibernate for the winter.  Those that are still around will be new queens that are topping up their internal reserves with nectar.  Most of these will be large Buff-tailed individuals who can be heard before they are seen because of the amount of noise that they make.  If we provide the flowers, they will forage.

    The woods, fields and hedgerows have had no flowers for a couple of months now but our gardens continue to have colour.  In September, on a three-kilometre survey of farmland in the Chilterns we spotted only 5 bumblebees while, at the same time, an Autumn-flowering Caryopteris in our garden had a similar number of bumbles foraging together.  That shows how important our winter-flowering garden shrubs are.  The custard-yellow blooms of Mahonia are valuable as a food source in January but only if they do not fall victim to tidy-minded gardeners who prune them in October!

    Some gardens do not have room for shrubs but low-growing plants like White dead nettle, Comfrey, and Hellebore can be grown against a fence, wall or hedge and they will bloom for many weeks.  They will add terrific value to any new wildlife facility even where public access is a factor.  These margins can be boosted with primroses and native daffodils to provide spring forage, biodiversity, cover for small animals, and visual interest for humans.

    What do bumblebees have in common with woolly mammoths and yaks?  Well, they are round and hairy because they evolved to survive in cold climates.  As the world becomes warmer, the bumbles find it increasingly difficult to cope with our summers, even by taking a siesta in the middle of the day.  (Oh yes, they do!)  Furthermore, a recent study showed that Borage plants grown at 26C rather than 21C produced fewer flowers with less nectar and pollen.  This resulted in a 75% fall in the number of visits by Buff-tailed bees.  Our pollinators need as many flowers as we can possibly provide as they respond to global warming.  Flowering plants evolved in parallel with pollinators over millions of years and although bees can change their behaviour in decades, plants cannot react nearly as quickly and so the balance is being upset.

    The Wild Cookham website has useful descriptions and pictures of UK bumblebees under the heading “Bumblebee News”.

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