Here is the text of the latest article for our village magazine. Like the first, second, third and fourth articles, the intention is to educate a lay audience and get them thinking about the natural world around them, the stresses vulnerable species face, and what they can do.
Bee Buzz – Winter bees
On cool mornings, you may have observed a butterfly languidly unfurling its wings in a patch of sun to absorb warmth before taking off a few minutes later. This is because, unlike mammals which generate their own heat, insects are cold-blooded – their muscles are virtually paralysed until warmed-up by an external heat source. Honeybees are the same and need their powerful flight muscles to be nicely warmed-up in order to fly. Bumblebees are a little hardier and can be seen operating at slightly lower temperatures than honeybees, gathering nectar earlier in the morning and visiting flowers in deeper shade. So with the onset of colder days, all insects are eventually forced to curtail their activities and ‘disappear’ from our gardens – for honeybees their winter period starts when the ambient temperature falls below 8-10C – usually late October for this part of the UK.
Various species of insects have different strategies for surviving the winter cold. Most species become completely dormant, either as a single hibernating fertile adult (like queen wasps and bumblebees), as pupating larvae (many beetles), or as eggs (the strategy used by solitary bees like masons, miners, carders, etc) – emerging as adults in the Spring. But honeybees (and ants) do not hibernate, instead they build up winter-stores and cluster together for warmth as a colony in the well-insulated cavity of their hive (nest). Their honey stores and colony-warmth allow for a low level of activity, so they are not actually dormant they are just living more slowly.
As the external temperature continues to drop, the edge of the cluster in the hive is sustained at 8C by the bees gently vibrating their wing muscles to generate heat. Remember if bees get too cold, below 8C, they can not move, this means they will drop off the cluster and die. So, much like penguins, they all take turns being heat generators exposed on the cold outside of the group, except for the Queen who is always kept safely at the warm centre. Very gradually, over winter, the cluster migrates through the hive as it eats its way through the stores. By the way, bees do not defecate in the hive and so have to hold in their waste over much of winter – but on rare warm sunny winter days, if the hive is in direct sunshine, you may see a mass of them dash out and fly close to the entrance of the hive on brief ‘cleansing’ flights!
Of course, a colony’s winter stores are finite – the success of a summer’s ‘harvest’ can vary and also winter extend for an unpredictable period, therefore the stores are to be carefully guarded and frugally managed. To help with this, the number of bees within the colony is reduced from the summer high of up to ~60,000 to a winter low of 5-20,000. This is mainly achieved by the Queen laying a decreasing number of eggs with the onset of autumn; thus as the mass of summer-born bees die off, fewer new bees are hatched, and so the colony size is reduced. However, another strategy the honeybees employ is to evict the now useless male bees, the drones, en-masse: it’s too late for mating (the Queens are already carrying within them all the sperm they will ever need), drones do not gather stores but they do consume them, and there is no point keeping excess mouths to feed. I try not to look, but you can sometimes see huddles of drones trying to get back in the hive and being ruthlessly excluded by the “bouncers” at the hive entrance.
This year, the dryness of early summer followed by a wet July and August led to a country-wide dearth of nectar, resulting in a particularly poor honey crop for winter stores, and has meant beekeepers have had to feed their colonies significant quantities of sugar syrup to ensure they can survive the oncoming winter – which is forecast to be long and hard. It really makes you think about how our local crop yields are so sensitive to the weather patterns.
Keeping bees has opened my eyes to the detail and interconnectedness and value of our natural environment, the plants, the animals and the weather – even mundane ivy strikes my eye differently these days and I welcome its abundance as, untrimmed and allowed to flower it regularly provides the last viable nectar source of the year.
As I write this on a sunny day in mid-October, my bees, hard-working to the end, are still frantically gathering in the last of the food available – in addition to the ivy, I can see some of them carrying yellow and orange pollen, and this tells me they have most likely found some good local sources of Himalayan Balsam and Goldenrod. As I observe them busy at the hive entrance, I reflect on how, as the days grow colder, I will see them less and less until I see them no more, until next year – assuming of course that they survive the winter. I heft the hives, feeling their reassuring weight – the bees have enough stores at last – hope for the Spring.