Bees tend to stop flying when the environmental temperature drops below around 8 deg C but they still remain active in the hive. Normally this is a 'good thing'. However, a busy bee is a hungry bee, and a hungry bee needs food. In winter, when a colony's stashed away food has to last through to March, hungry bees can be the undoing of an otherwise successful hive as they chomp their way through the precious honey and have no way of replacing it as its too cold to fly.
So far, this winter has all the halmarks of being one of those annoying mild and wet ones; no snow, few frosts and interminable showers and longer spells of rain with a glimmer of sun every few days. This is far from ideal for our bees. As temperatures remain relatively high the colony has no need to form the tight cluster that they need to retain heat. When tightly clustered the bees are able to dramatically reduce the amount they eat and so ecke out their stored supplies until well into springtime. Without this tight clustering it is entirely possible that a colony can starve itself by consuming everything it has kept before the first of the new year's nectar appears and the weather is good enough to fly.
As usual, this places the bee wrangler in a quandary - to feed or not to feed. And, as with every other year it seems, the answer depends on your view of the impact of intervention. Some bee herders take the view that they should feed irrespective of the weather, a prophilactic intervention 'just in case'. Others take the view that they should never intervene as this would weaken the evolutionary strain of bees - 'they will survive if they are meant to survive' and so they don't want to do anything that will mean that next year the colony will have a greater dependancy on human intervention as they will have started to loose their genetic trigger to cluster and conserve food.
It is 'well known' that certain sub-species of bee have different food consumption rates in winter. The original british black bee is said to be very frugal, probably because it is used to having to deal with our unpredictable weather patterns. The italian bees tend to be more exuberant in many aspects of their lives, and will gannet through a colony's stores in very short order, probably as a result of surviving the relatively short mediterranean winters, and then starve long before Christmas. All our colony's are hybrid bees - mongrels if you will - so their performance over winter will vary according to the story of their origins. However, as I've been watching bees for a few seasons now, it appears to me that the average winter bee in some colonies seems to have a darker countenance than their summer relatives. Its almost like a genetic switch is thrown and the winter bee has more of the british black's characteristics than its more italian summer bee version. Please note that I've not yet found any empirical evidence for this observation so don't hold me to any of my theorising. But I do know that we humans exhibit the ability to switch genes on and off (an emerging aspect of genetic science called epigenetics) by doing simple things like changing what we eat, so why shouldn't bees be able to switch 'frugality' genes on and off using environmental factors as a trigger. It may be that these frugality genes also bring about changes in physical appearance, hence the apparent colour change as well.
A flip side to this idea is that the italian bees have the 'well known' propensity to build a colony's numbers up quickly when the nectar flow begins in spring; larger numbers of bees can more quickly replenish much depleated stores. Whilst this sounds great in principle for a mediterranean climate it may also bring about the demise of a colony here in the UK as lots of energy is required to grow bees and if the timing is out, or the weather turns wet or cold for a spell, the colony can quickly starve before its able to begin feeding again (as happened to some of mine with the cold snap in March last year). Darwinian selection must the favour colonies that get this timing right in most years so bringing on a genetic line of bees suited to that local climate. This would explain why the way bees procreate, effective hybridisation, has allowed them as a species, to survive extremes of climate change and to be found surviving in most habitable areas of the world. So, as I've discussed before, there is a strong argument in favour of limited intervention if we want bees that are aclimatised to our locality - letting the less suitable colonies die off and allowing the more suitable ones to show themselves as survivors (and using these to split from in the spring to make our new colonies).
It is also a very strong argument to support the request for a ban on the importation of queens to the UK; the imact of these alien genetics from stranger climes disrupts the natural hybridisation of our local bees to create strong genetic lines that can more easily survive in our UK climate (see the Natural Beekeeing Forum for more on this).
Food for thought as I face digging out the mulch in the chicken run (many thanks Richard and Mandy for the replacement chippings). May I wish you all a Happy New Year of beeness.