From hieroglyphics to higher priests, parliaments and charlatans, the beehive has represented an ideal society, one in which all members work harmoniously together for the greater good of the community. A more careful observation reveals that humanity is not the sole domain for selfish behavior, and the unity that characterizes a honey bee colony is highly vulnerable to the persistent threat of destabilization from within its own population. Inside the beehive, ideology gives way to reality, and an ancient cold war rages on. Conflict waits patiently just below the surface, as a delicate balance of power among partially related factions is mediated by the presence of their queen - the colony’s only fertile female.
Barely a week old, the virgin queen flies from the hive to mate with a dozen or more drone. The offspring of each drone forms a subfamily whose members are known as “supersisters” because they are more closely related to each other than to other members of the colony (half-sisters). Predictably, the number of subfamilies equals the number of drone that mated with the queen. This uneven relatedness is the basis for reproductive competition in colonies that have become hopelessly queenless.
In an evolutionary context, fitness refers to an organism’s reproductive success. The goal is to survive long enough to produce offspring, ensuring its genotype is represented in the next generation. Although a honey bee worker cannot mate, some level of fitness via reproduction is still possible through the production of male offspring from unfertilized eggs. In a queenright colony, this is not an option. Allowing a worker to produce her own drone would result in her having a fitness advantage over the other workers. This gives rise to compromise, such that all workers will experience an equal gain in fitness by rearing only the offspring of the queen, with whom all subfamilies are equally related. Any eggs selfishly laid by a worker are swiftly destroyed. Queen and brood pheromone play a supporting role in this suppression of worker reproduction by alerting the colony to their presence; however, these pheromones do not function as a sterility drug. Ultimately, it is the social behavior of worker policing that results in the queen being the only female reproductive in a honey bee colony.
With the loss of the queen and subsequent failure to rear a replacement comes the colony’s rapid destabilization, as cooperation in rearing the queen’s offspring is no longer an option. Workers from all subfamilies seize the opportunity to maximize their individual fitness by laying eggs. If that fails, the next best thing is to rear the sons of a supersister and destroy the eggs laid by a half-sister. Evidence of this reproductive competition is found in the highly disproportionate number of laying workers that originate from the same subfamily. These dominate laying workers then produce a queen-like pheromone that reestablishes the suppression of egg laying by other workers. Unfortunately, the colony still cannot produce a female and is fully aware they lack a viable queen, evidenced by the desperate construction of supersedure cells around unfertilized eggs.
At this point, the beekeeper may try to “help” the colony by introducing a mated but unrelated queen. These attempts will be unsuccessful, not because the colony thinks it already has a queen, but because an unrelated queen has nothing to offer the colony in its pursuit to pass its genes to the next generation. She is, in fact, a clear threat and will be treated as such. The bees that reject her will be dead in a few weeks, regardless. Accepting a foreign queen can’t change that, and it’s not about their own physical survival, anyway. It’s not about raising unrelated offspring. The goal of a laying worker colony is to maximize its fitness by producing offspring of its own, and that means rearing as many drones as possible before the colony dies.
Even in the absence of laying workers, the instinct of any queenless colony is to reject an introduced queen. Of note, however, is the readiness with which a queenless colony will rear a new queen from unrelated eggs and larvae, despite its rejection of the queen that produced them. Perhaps this can best be explained by the extreme habitual behavior that characterizes a honey bee. The pheromone cocktail produced when there are eggs in the hive but no queen signals the need for queen rearing to begin. It’s been this way since forever. The question really isn’t why a queenless colony might reject an introduced queen or her eggs but why it would ever accept them. It’s akin to colony-level suicide.
The advantage here is with the beekeeper. Considering the very small size of the bee brain, there are many schemes to employ or unnatural scenarios to create that can either outsmart or thoroughly confuse a honey bee colony. It did not evolve in an environment in which its nest suddenly becomes host to thousands of foreign eggs or an unrelated queen. Sometimes all that’s required to make a colony queenright is a smoker to briefly cover-up unfamiliar pheromones. There may be times when not even smoke is needed. But there are also times when, despite the creative efforts of the beekeeper or the long history of programmed response, a queenless colony simply will not rear a new queen. This, too, may be the result of reproductive competition among subfamilies and the primal need to maximize fitness.
Purely as a matter of speculation, suppose in the process of splitting a colony the beekeeper divides it in a way that eggs and young larvae in the split all originate from a subfamily that is not well represented in the transferred adults. Nepotism by honey bees during queen rearing has been documented in several scientific papers. Without the opportunity to raise a supersister as the next queen, workers from a subfamily that became dominant after being split from the parental hive may have the option of rearing the offspring of a half-sister queen or producing offspring of their own in the form of drone. The latter would result in the greater gain in fitness and require the foiling of any attempts by other colony members to rear a new queen.
All that may be a stretch, but these things are not just interesting to think about but also offer a more practical application for the desperate beekeeper whose queenless split (or other queenless colony) won’t rear a new queen: Try offering eggs/larvae from a different source. Or add another frame of bees from the parental hive in hopes of better balancing the distribution of subfamilies. It could be the difference. At the very least, the awareness of competing colony factions offers a fresh perspective on colony behavior that may make better sense to the honey bee keeper.
Colony integration and reproductive conflict in honey bees. PK Visscher – 1998
Differential reproductive success among subfamilies in queenless honeybee colonies. Martin & Oldroyd - 2004
Reproductive competition in queenless honey bee colonies. RE Page, GE Robinson - 1994
Possible causes of reproductive dominance during emergency queen rearing by honeybees. KE Osborne - 1999
Levels of selection in a social insect: conflict and cooperation during queen replacement. Tarpy & Seeley – 2004
Kin discrimination within honey bee colonies: an analysis of the evidence. MD Breed, CK Welch, R Cruz - 1994