Dr. Hannes Bonhoff
Domestication is the transformation of a population of organisms away from its wild form in order to fulfill human wants. It requires control over reproduction to select for certain traits. For honey bees, the colony represents the primary organism, so-called superorganisms. Their reproduction is controlled by queen rearing, isolated mating stations, instrumental insemination and various ways to create new superorganisms with the mated queens. However, these methods have been widely accessible for only a century. ¹ While the majority of our domestic animals were bred into existence thousands of years ago, the domestication of the honey bee has only recently begun to gain momentum. Honey bees are currently assessed to be merely semi-domesticated.¹ But do not be tempted to underestimate the ongoing process of domestication, for its effects can be devastating. How devastating domestication can be is explicitly demonstrated by the only fully domesticated insect to date, the silk moth.² While the domestication of its wild ancestor has enhanced the production of silk, the moth has lost its ability to fly and needs human assistance to mate. It also lacks fear of predators. These changes render the domestic silk moth incapable of persisting without its domesticator. Luckily for the wild silk moth, the domestic stock is reproductively isolated, thereby limiting the spread of such detrimental traits. The wild moth is therefore able to continue its existence and evolution in parallel with its domestic relative. Honey bees are not so lucky since they mate over much larger distances and apiaries with bees subjected to domestication are widely spread across the land. What beekeepers do with their bees therefore directly affects those in the wild. A successful domestication would not only risk to create a honey bee fully dependent on human assistance; the spread of detrimental traits would risk pushing the wild honey bee into extinction. In order to prevent such a dire outcome, it is imperative to understand the mechanisms of the ongoing domestication. Fortunately for us, the process of domestication and its effects are well understood and can be explained and predicted by evolutionary biology. The underlying scientific theories are so well supported by such a sheer mass of evidence that we do not have to wait for specific studies on the honey bee to shed light on its domestication. Similar cases have already been studied, such as the wild salmon threatened by interbreeding with salmon that escaped from domestication.³ Science allows us to predict the effects of our doings right here and now.
Swarming is key To understand how a wild species may go extinct, we can look at the cause for it to persist. The life-span of honey bee superorganisms is only a few years.⁴ In order to prevent a population from vanishing, the dead have to be replaced. Ultimately, it therefore is the reproduction to create new superorganisms that safeguards the existence of the wild honey bee. Although subjected to human-mediated gene flow, the wild honey bee is still around not because of the life-span of superorganisms but because they swarm. As it turns out, the ongoing domestication targets this very reason for the continued existence of the honey bee both directly and indirectly.
One of three swarms from a wild superorganism in Sweden 2020 (Photo: Hannes Bonhoff) One of the major goals in selective breeding is to reduce the swarming tendency. If drones spread a low propensity to swarm into the wild, the affected superorganisms will produce fewer offspring. As soon as the number of swarms no longer is sufficient to compensate for the superorganisms that died, the entire population declines and may eventually disappear. The honey bee does not even have to lose the ability to swarm for the species to no longer be viable without human assistance; it is enough to reduce the tendency to swarm below a certain unknown threshold.
The ability to swarm may be lost, however, if humans consistently create new colonies manually, prevent swarming or even interrupt the swarming process by, for instance, collecting the swarms before they move into their new homes. Swarming is such a complex process⁵ that it probably only takes a single or just a few deleterious mutations or recombinations⁶ for it to go wrong. While harmful genetic variants are eliminated in the wild by means of natural selection, they can be retained, spread and allowed to accumulate when this selection pressure is removed. If bees are no longer allowed to produce new superorganisms by themselves, evolutionary theory predicts that sooner or later they will lose the ability to do so. Systematic assistance such as feeding, cleaning bottom boards or installing mouse guards works in a similar manner. This removes the selection pressure for the bees to take care of themselves and instead allows the spread of genes that are detrimental in the wild. The systematic help of individual superorganisms therefore has the opposite effect on the species in the long run.
How long it may take for domestication to lead to the extinction of the honey bee in the wild depends among others on the ratio of superorganisms subjected to either domestication or natural selection. A large wild population may be able to weed out the detrimental traits spread from domestication. If the wild superorganisms are outnumbered by those subjected to domestication, on the other hand, the harmful gene flow may be too strong and the end of the wild honey bee may come surprisingly soon. According to a recent study, the latter is the case throughout Europe.⁷ A closer look at the situation in Sweden makes such dark predictions feel uncomfortably realistic.
A case study
One fast track to domesticate the honey bee is to simply classify it as domesticated. This effectively removes any protections reserved to wildlife. The situation in Sweden has even progressed one step further: without explanation or citing references, the Swedish Red List proclaims that the honey bee is not only fully domesticated but even an introduced species, thereby boldly contradicting established fact⁸.
With the Red List as its reference, the Swedish Society for Nature Conservation refers to honey bees as tamed and fully dependent on human assistance. Swedish researchers advocate in newspapers to exclude the honey bee in the ongoing efforts to save the bees and highlight that honey bee superorganisms in the wild are poised to die after just a few years, thereby suggesting that the species is incapable of self-sustained life. The latter is remarkable given the fact that solitary and bumble bee species are doing just fine despite the fact that individuals are able to survive no more than a single year.
Without protection from conservationists, the wild honey bee is fully exposed. In efforts to control American foulbrood, thousands of wild superorganisms have been killed by bee health officials (see graph). Ironically, it is Swedish research that shows that the problems with American foulbrood may primarily be dependent upon apicultural practices and that the disease may not result in superorganism mortality in the absence of such practices⁹. Instead of adopting sustainable methods, the killings are even justified as a precaution.
Source: Jordbruksverket Bitillsyn
Sweden has the lowest density of potential nesting habitat in trees throughout Europe.⁷ This is an effect of the forestry industry which is estimated to cut down virtually all unprotected old-growth forests within the next two decades. Additionally, replacement tree plantations are harvested well before suitable cavities for habitation can form. A major problem with the sanctioned killings by bee health officials is that the corresponding cavities are either destroyed or sealed off. Without nesting habitat, the wild honey bee cannot exist. Indeed, the graph looks very much like an eradication.
A dwindling or virtually non-existing wild population would set the stage for a swift domestication. Many beekeepers allow their queens to mate freely with whatever drones they encounter. If these drones originate from wild superorganisms, the resultant gene flow would counteract or potentially nullify the effects of the domestication for the bees of such beekeepers. If drone congregation areas are dominated by drones from apiaries subjected to domestication, on the other hand, the effects can accumulate and become fixed.
The two predominant Swedish beekeeping associations exclusively teach conventional methods that will directly or indirectly lead to the domestication of the honey bee. Consequently, the vast majority of beekeepers desire the same traits and practice beekeeping uniformly with swarm prevention and human-led production of new superorganisms. Moreover, queen breeding is commonly seen as the pinnacle of beekeeping, something to strive for. There are numerous island mating stations allowing queen breeders to control the origin of drones and instrumentally inseminated queens are available for purchase. Moreover, it is official recommendation from the bee health department to requeen hives regularly.
There also is a conservation association for the native subspecies Apis mellifera mellifera, which has succeeded in saving a few lineages from the mixing with imported subspecies. But instead of releasing the bee back into the wild, the conservation association now domesticates it by practicing conventional beekeeping and selective breeding, with the reduction of its swarming tendency as a primary goal, which they call "improvement".
The above combined circumstances make Sweden a frontrunner to become the first country to fully domesticate the honey bee.
Apis mellifera domesticus
If individual bee breeders consistently control the reproduction of their bees, then it is only a matter of time before the advent of a domestic honey bee. What characteristics will qualify this bee as being fully domesticated, a new subspecies distinct from the honey bee as we know it?
Conceivable attributes of a domesticated honey bee are a degree of tameness which renders protective clothing and smokers obsolete, an increased fertility of queens yielding significantly larger superorganisms and honey harvests than can be achieved by mere management and a propensity to swarm reduced so markedly that swarm prevention is no longer necessary. Queens carrying any of such traits may be so well sought after that they could quickly be spread far and wide.
What about the qualities relating to the bee's ability to persist in the wild? Will Apis mellifera domesticus possess equally detrimental characteristics as the domestic silk moth: a lack of fear towards predators, loss of the ability to fly and need for human assistance for mating?
The breeding for docility towards humans most likely lowers the bees' capacity to defend their hives against other intruders. On the level of the superorganism, such a lack of defense could indeed be interpreted as being without fear of predators. And if the mating in a breeding operation is consistently performed by means of instrumental insemination, then the accumulation of deleterious genetic variants may result in the loss of the bees' ability to mate. How about the ability to fly?
A prerequisite for pollination and the production of honey is that foragers are able to fly. Since these are the very reasons for conventional beekeeping, forager bees will certainly continue to roam the sky. But identical sets of genes can be expressed very differently. For queens and drones, the consistent use of instrumental insemination by individual bee breeders can indeed lead to an inability to fly since it is no longer required in such a case. As with the silk moth, this could simply occur by means of an increase in body weight, for instance, in order for queens to maintain ever larger brood nests.
But individual bees, in relation to the superorganism, merely represent the equivalent of cells in multicellular animals. Will the fully domesticated honey bee superorganism be able to fly? While remaining sessile for most of its lifecycle, the superorganism performs one of nature's greatest spectacles by taking flight as a swarm in order to make room for its offspring. But as outlined above, swarming is targeted both directly through selective breeding and indirectly by means of swarm prevention and the human-led creation of new superorganisms. Evolutionary theory predicts that the domestic honey bee superorganism will eventually lose the ability for functional flight, thereby leaving it fully dependent on human assistance.
The risks of the ongoing domestication are at least two-fold. Both the existence of the wild honey bee and the beekeepers' bees' ability for self-sustained life are at stake. Imagine forests without bee trees or Tom Seeley's book "Honeybee Democracy" reduced to a history book by the future domestic honey bees' inability to swarm. But as of yet, it is neither too late nor too difficult to turn the tides. Populations of wild honey bees simply need suitable nesting and foraging habitat to thrive. What about the bees in apiaries?
The author installing a loghive for wild honey bees in Sweden (Photo: Tina Kolhammar)
Honey bees pollinate and produce honey and wax even without being domesticated. The primary reason for domestication is to maximize one's harvest within the scope of current beekeeping methods. The biology of the honey bee, however, already enables a substantial increase in harvest via simple management, e.g., by adding honey supers. The same applies to the bees' defensiveness. A few puffs with a smoker allows you to harvest without getting stung. Thus, the domestication of the honey bee boils down to the ethically highly questionable urge to want even more from each and every superorganism by means of swarm prevention.
How then would beekeeping look like without domesticating the bee? The primary characteristic is to let the bees swarm into a cavity of their own choosing and to allow them to handle queen succession and mating on their own. Instead of manually creating new superorganisms, one would let the bees do all the work themselves. In areas without nesting habitat, this requires the placement of empty hives at suitable locations based on the bees' nest-site preferences.⁵ These hives do not have to be brought back to a crowded apiary, but would ideally be allowed to remain where they have been occupied. Secondary characteristics are to minimize any form of systematic human assistance and to mimic the hollow tree with the hive design.
A beekeeping without domestication only requires very little work in relation to the pollination and harvest to be gained. Those who want more harvest could increase their number of hives instead of increasing the harvest per hive. Moreover, while swarm prevention is the equivalent of captivity for superorganisms, a domestication-free beekeeping allows the bees to live freely. Such a form of beekeeping even has the potential to result in sustainable relationships between the bees and their pathogens and parasites.
Apart from the goal to lower the bees' tendency to swarm, many breeding programs also seek to select for mite-resistant bees. It is established fact, however, that the problems attributed to mites are to a large degree caused by such management practices as swarm prevention, crowded apiaries and large hives.¹ Evolutionary theory predicts that the substantial horizontal transmission occurring in conventional apiaries fosters ever more harmful pathogens and parasites.¹⁰ This renders any beekeeping operation with hives placed next to one another unsustainable. The transmission during swarming, on the other hand, is the very reason for the evolution of benign pathogens and parasites and tolerant or resistant bees.¹⁰ Instead of breeding a bee that can cope with the conditions in conventional apiaries, the beekeeping methods could be adapted to our current state of knowledge to avoid domestication and achieve sustainability.
I encourage those who keep bees to ask themselves whether they find it ethically justifiable for them to contribute to the domestication of the animal they are taking care of. And, if the answer is no, then do not hesitate to make a difference for the bees in your area and beyond. You can protect and provide habitat for wild honey bees, adapt your methods to become domestication-free and contact beekeeping associations and conservation organizations to address the subject.
If we really love bees, we should respect the way they are.
T.D. Seeley, The Lives of Bees, Princeton University Press (2019)
T.P.S. Chauhan & M.K. Tayal, Mulberry sericulture, In: Omkar, editor, Industrial Entomology: 197–263, Springer Verlag (2017)
G. Bolstad, et al., Gene flow from domesticated escapes alters the life history of wild Atlantic salmon, Nature Ecology & Evolution 1:0124 (2017)
R.F.A. Moritz & E.E. Southwick, Bees as superorganisms, Springer Verlag (1992)
T.D. Seeley, Honeybee Democracy, Princeton University Press (2010)
A. Wallberg, et al., Extreme Recombination Frequencies Shape Genome Variation and Evolution in the Honeybee, Apis mellifera, PLoS Genetics 11(4):e1005189 (2015)
F. Requier, et al., Contribution of European forests to safeguard wild honeybee populations, Conservation Letters 13(2):e12693 (2020)
De la Rúa, et al., Apis mellifera, The IUCN Red List of Threatened Species (2014)
I. Fries, et al., Vertical transmission of American foulbrood (Paenibacillus larvae) in honey bees (Apis mellifera), Veterinary Microbiology 114(3–4):269–274 (2006)
I. Fries & S. Camazine, Implications of horizontal and vertical pathogen transmission for honey bee epidemiology, Apidologie 32(3):199–214 (2001)