Bee Colonies — Reading

Passage

A A honeybee colony is often described as a single organism rather than a collection of insects, and the comparison is more than poetic. A summer colony holds perhaps forty thousand workers, one queen and a few hundred males, and almost none of them can survive alone for long. Workers are sterile females whose duties change with age: cleaning cells in the first days of adult life, then feeding larvae, then building comb, then guarding the entrance, and only in the final weeks flying out to forage. The queen does not command any of this. She lays eggs — up to two thousand on a good day — and the colony organises itself around chemical signals rather than instruction. B The best-known of those signals is not chemical at all. A forager returning from a productive patch of flowers performs a looping run across the vertical face of the comb, waggling her abdomen along the straight portion. The angle of that run relative to vertical encodes the direction of the food relative to the sun; the duration encodes the distance. Karl von Frisch worked this out in the 1940s and received a Nobel Prize for it. That a small-brained insect communicates an abstract vector to nestmates in the dark remains one of the more remarkable findings in animal behaviour. C The economic argument for bees is usually made through pollination. Roughly a third of the food humans eat comes from crops that benefit from animal pollination, and honeybees are the pollinator most easily moved to where they are wanted. The qualification matters: many of those crops would still set some fruit without them, and wild bees, hoverflies and other insects do a substantial share of the work. Almonds are the clearest exception, being entirely dependent on insect pollination, and the Californian almond bloom now requires the seasonal delivery of tens of billions of bees. D Beginning around 2006, beekeepers in North America and Europe reported hives emptying in a particular way: adult workers vanishing over days, leaving the queen, the brood and untouched stores of honey behind. The pattern was named colony collapse disorder. Two decades of investigation have not produced a single cause, and the current consensus is that there is not one. The varroa mite, a parasite that feeds on bees and transmits viruses, is implicated almost everywhere it occurs. So are neonicotinoid pesticides, which do not usually kill outright but impair navigation and immunity at doses bees routinely encounter. E Two further pressures are less often discussed. Modern arable landscapes flower intensely and briefly, then offer nothing, so a colony can starve in a green field. And commercial pollination involves loading hives onto lorries and driving them across a continent, which exposes colonies to each other's diseases and to the stress of confinement. A colony weakened by any of this may then fail to survive an ordinary winter, which is why annual losses are a misleading headline figure: the winter is rarely the actual cause. F Policy has moved, unevenly. The European Union restricted three neonicotinoids on flowering crops in 2013 and broadened the ban in 2018; other jurisdictions have not followed. Agri-environment schemes now pay farmers to leave flowering margins, and the evidence that these help wild pollinators is reasonably good. Meanwhile the number of managed honeybee hives worldwide has actually risen, because beekeepers replace losses by splitting surviving colonies — a fact sometimes cited to argue the crisis is overstated. G That argument mistakes what is at risk. Managed honeybees are livestock, and livestock numbers can be maintained at cost. The harder problem is the wild pollinators that nobody counts and nobody replaces, several hundred species of which are declining across the same landscapes. A world that keeps its honeybees while losing its bumblebees and solitary bees would look reassuring in the statistics and be considerably poorer in fact. H Public responses to the crisis have tended to focus on the most visible intervention: planting flowers. Wildflower verges, pollinator gardens and 'bee highways' along road margins have become common policy gestures in cities across Europe and North America, and they are not without value — a diverse and continuous supply of flowering plants genuinely helps pollinators of every kind. But researchers who study wild bee decline caution that flower planting alone addresses only one of several pressures, and arguably not the most severe one. Pesticide exposure, habitat fragmentation and the loss of undisturbed nesting sites — most wild bees nest in bare ground or old wood, not hives — are harder to fix with a single afternoon of planting, and harder still to turn into a photograph for a council newsletter. There is a risk that visible, low-cost interventions crowd out less visible, more expensive ones: restricting pesticide use, leaving field margins unmown, or protecting the marginal land that intensive agriculture has the least reason to preserve. Flowers help. They are not, on their own, a policy.

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