Wednesday, 15 August 2012
The Importance of Being a Drone
At the 2012 UK Natural Beekeeping Conference, held in August at Emerson College, East Sussex, I included in my opening speech an idea that had only occurred to me a few weeks previously, but which struck me as being fundamental to the way I had come to think about bees. Some other people at the conference also considered that the idea deserved further exploration, so I thought it worth writing more about it.
While 'natural beekeepers' are used to thinking of a honeybee colony more in terms of its intrinsic value to the natural world than its capacity to produce honey for human use, conventional beekeepers and the public at large are much more likely to associate honeybees with honey. This has been the main cause of the attention given to Apis mellifera since we began our association with them just a few thousand years ago.
In other words, I suspect most people - if they think of it at all - tend to think of a honeybee colony as 'a living system that produces honey'.
Prior to that first meeting between humans and honeybees, these adaptable insects had flowering plants and the natural world largely to themselves - give or take the odd dinosaur - and over a span of tens of millions of years had evolved alongside flowering plants and had selected those which provided the best quality and quantity of pollen and nectar for their use. We can assume that less productive flowers became extinct, save for those that adapted to using the wind, rather than insects, to spread their genes.
For all of those years - perhaps 130 million by some counts - the honeybee continuously evolved into the highly efficient, extraordinarily adaptable, colony-dwelling creature that we see and meet with today. By means of a number of behavioural adaptations, she ensured a high degree of genetic diversity within the Apis genus, among which is the propensity of the queen to mate at some distance from her hive, at flying speed and at some height from the ground, with a dozen or so male bees, which have themselves travelled considerable distances from their own colonies. Multiple mating with strangers from foreign lands assures a degree of heterosis - vital to the vigour of any species - and carries its own mechanism of selection for the drones involved: only the stronger, fitter drones ever get to mate.
An unusual feature of the honeybee, which adds a species-strengthening competitive edge to the reproductive mechanism, is that the male bee - the drone - is born from an unfertilized egg by a process known as parthenogenesis. This means that the drones are haploid, i.e. have only one set of chromosomes derived from their mother. This in turn means that, in evolutionary terms, the queen's biological imperative of passing on her genes to future generations is expressed in her genetic investment in her drones - remembering that her workers cannot reproduce and are thus a genetic dead end.
So the suggestion I made to the conference was that a biologically and logically legitimate way of regarding the honeybee colony is as 'a living system for producing fertile, healthy drones for the purpose of perpetuating the species by spreading the genes of the best quality queens'.
Thinking through this model of the honeybee colony gives us an entirely different perspective, when compared with the conventional point of view. We can now see nectar, honey and pollen simply as fuels for this system and the worker bees as servicing the needs of the queen and performing all the tasks required to ensure the smooth running of the colony, for the ultimate purpose of producing high quality drones, which will carry the genes of their mother to virgin queens from other colonies far away. We can speculate as to the biological triggers that cause drones to be raised at certain times and evicted or even killed off at other times. We can consider the mechanisms that may control the numbers of drones as a percentage of the overall population and dictate what other functions they may have inside the hive. We can imagine how drones appear to be able to find their way to 'congregation areas', where they seem to gather when waiting for virgin queens to pass by, when they themselves rarely survive more than about three months and hardly ever through the winter. There is much that we still do not know and may never fully understand.
An important aspect of this way of looking at the honeybee colony is that it calls into question many of the practices of 'modern beekeeping' - by which I mean post-Langstroth, post-1850 beekeeping - which has always been focussed on honey production above all else. From the point of view of our evolutionary model, many modern practices have been implemented with the specific objective of suppressing the raising of drones: thus running directly counter to the evolutionary interests of the queens.
In support of this thesis, we can cite the invention of wax foundation, impressed with the cell pattern of worker bees, deployed with the specific purpose of encouraging the colony to raise the maximum number of workers and the minimum number of drones. We can also lay some blame at the door of those who decided that frames should be spaced close together, thus allowing only for the building of worker cells and forcing drone cells to the outer fringes of the comb. More recently, we can mention and condemn the encouragement from certain quarters to 'cull' drone pupae with the intention of reducing the population of Varroa destructor in our hives.
Other recent practices, such as the sterilization of woodwork and the use of plastics ensure that hives will be relatively free from any of the other minute creatures that evolved to sharing hollow logs and trees with bees. Yet now we are discovering that some of these little bugs may well hold the secret of how pests and diseases are kept at bay. Significantly, experiments with mites of the Stratiolelaps genus are proving successful at controlling Varroa and I suspect that the humble earwig and wood louse have parts to play.
The almost universal use of miticides over the last half century has turned our bee colonies from models of biodiversity into sterile mono-cultures, at the expense of a multitude of moulds, fungi and insects whose functions and interactions we can only guess at. Who knows what concurrent damage the pyrethroids and neonicotinoids, widely used in our insane, toxic agricultural system may have done, not only to the bees but to the soil, which supports all life.
It seems to me that the history of modern beekeeping is replete with examples of anti-drone behaviour by beekeepers, from ignorance of their true role in the colony and in direct contradiction of the needs and instincts of the honeybee queen. Conventional beekeepers, however much they may protest their love and devotion for their charges, are in fact negating the wishes of the bees by focussing their efforts on the fuel of this intricate system, rather than its true purpose: the production of high quality drones, without which Apis mellifera is doomed as certainly as the dinosaurs.
So 'natural beekeepers', with their focus on creating close-to-ideal environments for the use of honeybees and working in alignment with the desires of their queens are best placed to assure the future of the species, so long as they do not succumb to undesirable 'modern' tendencies.