For thousands of years, beekeeping was a craft that passed from one generation to the next largely through observation and apprenticeship. The honeybee itself was understood in broad outline - queen, workers, drones, honey, comb - but the fine details of how a colony coordinates its activity remained obscure. The transformation of beekeeping into a scientific discipline began in the early nineteenth century with the invention of movable-frame hives, which allowed individual combs to be lifted out and inspected without destroying the colony. It has accelerated in recent decades as molecular tools have opened lines of investigation that were not previously available.

A. A honeybee colony is, in effect, a single reproductive unit whose members share most of their genes. A worker bee, unable to reproduce on her own, contributes to the colony's success by rearing the queen's offspring, who share about three-quarters of her genetic material - more than she would share with her own offspring if she could produce them. This unusual inheritance pattern, first explained by the British biologist W. D. Hamilton in the 1960s, is the conceptual key to understanding why such elaborate social cooperation can evolve. It has since been applied to ants, wasps, and other eusocial insects.

B. The day-to-day coordination of a hive depends on chemistry. Worker bees respond to pheromones produced by the queen; in her absence, the colony rapidly begins to rear a new queen and, failing that, breaks down into reproductive confusion. Worker bees also release alarm pheromones when the hive is threatened, recruiting defenders within seconds. Research over the last two decades has identified dozens of distinct pheromones, each with a specific function. The Swiss bee biologist Anna Richter has shown that the composition of the queen's chemical signature changes subtly through the season, which may explain the periodic variations in worker behaviour that beekeepers have long noticed.

C. The famous waggle dance, by which a returning forager communicates the location of a food source, remains one of the most elaborate animal communication systems known. The angle of the dance on the vertical face of the comb corresponds to the angle between the food and the sun. The duration of the waggle phase codes distance: approximately one second per kilometre for most European populations, though other races of the same species use slightly different scaling. Recent work has shown that bees can interpret the dance even when it is performed on a horizontal surface outside the hive, suggesting a more flexible cognitive system than was originally supposed.

D. The decision to swarm - a queen leaving the hive with roughly half the workers to found a new colony - is taken by a process that has been studied in unusual detail. Scout bees search for potential nest sites, return to the swarm clustered outside the hive, and perform waggle dances advocating their preferred location. Other scouts investigate the recommended sites and return to dance in their turn, either supporting the original proposal or promoting an alternative. Over a period of hours to days, the scouts converge on a single location that has attracted enough advocates. The process has been described as a form of distributed decision-making that achieves accurate results without any central control.

E. Disease and parasitism have become the dominant concerns of modern beekeeping. The Varroa destructor mite, which arrived in European populations from Asia in the 1970s, feeds on bee larvae and transmits a range of viruses. Colonies without active management typically die within a few years of infestation. The mite has resisted a succession of chemical treatments, partly because bees themselves are sensitive to many of the compounds that might kill the mites and partly because the mites reproduce quickly and evolve resistance. Research into bee genetics, initially motivated by pure biology, has contributed practical strategies in the form of lines of bees that can detect and remove infected pupae from their combs.

F. Colony collapse, the widespread die-off of colonies first widely reported in North America in 2006, appears to have multiple causes. Varroa mites, viral infections, nutritional stress from monoculture agriculture, and exposure to certain pesticides have all been implicated. Richter has argued that no single explanation accounts for the geographic and temporal pattern of losses, and that simultaneous pressures on multiple fronts are the most plausible description. Her colleagues' work on honey-bee genomics has identified genetic variants associated with resistance to specific viruses, but they have not found a single mutation that protects a colony across the full range of threats.

G. The ecological importance of honeybees, and of the many hundreds of species of wild bees that pollinate alongside them, is difficult to overstate. Roughly a third of the world's food crops require insect pollination. Almonds in California, apples in Pennsylvania, and squash across much of Mexico all depend on managed honeybee hives trucked in for the flowering season. Wild bees, including bumblebees and solitary species, contribute as much or more pollination in many landscapes but attract less public attention because they do not produce a commercial product. Richter has remarked that the modern beekeeper's trade has become entangled with conservation biology in ways that would have been unrecognisable a generation ago, and that the health of the managed colony has become, in effect, a proxy for the health of a much wider insect world.