The Plight of the humble bee  

The story of declining bee populations has been simmering for a few years now - The Times has an update on the situation in the UK - Plight of the humble bee.

Native British bees are dying out — and with them will go flora, fauna and one-third of our diet. We may have less than a decade to save them and avert catastrophe. So why is nothing being done? ...

On the face of it, the midwinter appearance of Bombus terrestris looks encouraging — a harbinger of the all-year summers that optimists look forward to. But this is precisely the problem. Contrary to what one might expect, says Goulson, a warming climate will not set the hedgerows buzzing. “Bumblebees evolved in the Himalayas. They are unusual among insects in that they don’t like warm weather.” Their thick fur coat is an aid to survival in a cool climate but an energy-sapping body-broiler in the heat. “This is why the southern hemisphere has no bumblebees.”

Once upon a time, for example, the great yellow bumblebee, Bombus distinguendus, which thrives in the cold and wet, was common throughout Britain. Now it has been driven so far northwards that it occurs on the mainland only within half a mile of the extreme north coast of Caithness and Sutherland. “So,” says Goulson, “it can go no further. It is probably doomed as a result of climate change.” Other species, too, are shrinking into local redoubts. The shrill carder bee, Bombus sylvarum, is now limited to the Somerset Levels, Salisbury Plain and the Thames Estuary, where much of its habitat is on brownfield sites and impossible to protect. Since 1980, the formerly common large garden bumblebee, Bombus ruderatus, has been recorded at fewer than 10 sites in the UK.

And so it goes on. As the entire insect world is being forced inexorably northwards, it may be hoped that other pollinators from southern Europe may be sucked into the vacuum behind them. Hoped, but not expected. Bumblebees are not like migrating birds — they do not fly for hundreds of miles between remote habitats. They are more like mammals, needing a continuous corridor of suitable habitats to move through. Without a linked route up through France, they are more likely to die out where they are.

Even if new species did arrive, they would be unable to take on all the work of the old. Many bumblebees, including all those under threat, are specialist feeders that depend upon — and pollinate — particular groups of plants. By the miracle of evolution, some species have developed long tongues, with which they can reach the nectar of deep-throated flowers. Without them, the plants could not reproduce. The incomers can offer no solution: their tongues are too short. The first casualties of the bumblebee exodus, therefore, will be some of the best-loved British wild flowers such as foxgloves, irises, red clover, comfrey, toadflax, tufted vetch… Soft fruit, oilseed and bean crops would also take a hit.

And that is the thin end of the long-term catastrophe that now stares us in the face. You take one brick out of the ecological wall, others crumble around it. Then more crumble, on and on until the edifice collapses. Ecologists call it an extinction vortex. You lose bees, you lose plants. You lose plants, you lose more bees. Then more plants, then other insects, then the birds and animals that depend on them and on each other, all the way up the food chain. But never mind animals — if you stretch the process far enough, you’re talking about humans.

The more extravagant, ocean-boiling scenarios of climate science have drama on their side, but the entomologists in their quiet way are just as scary. In his book The Creation, the world’s most celebrated biologist, E O Wilson, has spelt out what would happen if the vortex swallowed insects. “People need insects,” he says, “but insects do not need us. If all humankind were to disappear tomorrow, it is unlikely that a single insect species would go extinct, except three forms of human body and head lice… In two or three centuries, with humans gone, the ecosystems of the world would regenerate back to the rich state of near-equilibrium that existed ten thousand or so years ago… But if insects were to vanish, the terrestrial environment would soon collapse into chaos.”

Flowering plants would go first, then herbaceous plants, then insect-pollinated shrubs and trees, then birds and animals and, finally, the soil. Wilson corrects the generally held misapprehension that the principal “turners and renewers” of the soil are worms. That distinction more properly belongs to insects and their larvae. Without them, bacteria and fungi would feast on the decaying plant and animal remains, while — for as long as it was able to support them — the land would be recolonised by a small number of fern and conifer species. The human diet would be wind-pollinated grasses and whatever remained to be harvested from a fished-out sea. It would not be enough. Widespread starvation would shrink the population to a fraction of its former size.

“The wars for control of the dwindling resources, the suffering, and the tumultuous decline to dark-age barbarism would be unprecedented in human history.” Wilson concedes that we might survive quite happily without body lice and malarial mosquitoes. Otherwise, he says: “Do not give thought to diminishing the insect world. It would be a serious mistake to let even one species of the millions on Earth go extinct.”

But here again is a parallel with global warming. Changes have taken place that cannot be reversed, and further change is unstoppable. Unlike global warming, however, loss of insects has not inspired national governments or the UN to take expensive action to forestall it. The plight of the honeybee has been well documented if not well understood. The causes of colony-collapse disorder, in which bees disappear without trace from their hives, are debated as fiercely as the causes of climate change, with opinion dividing along very similar fault-lines determined often by vested interests.

Bee farmers and the European parliament blame arable farmers for killing or poisoning their bees with GM crops and careless use of insecticides. The arable farmers say their critics don’t know what they are talking about. Others suspect viruses, parasites or fungi. Some even blame radiation from mobile telephones for disrupting the insects’ navigational systems. Many think it likely that a combination of factors is at work — pesticides perhaps weakening the bees’ immune systems and rendering them defenceless against common pests and diseases (though again the arable boys won’t have it). Tim Lovett, president of the British Beekeepers’ Association (BBKA), suspects a combination of varroa mites, viruses and a vicious parasite called Nosema ceranae, a microsporidium that occupies some strange biological niche between animal and plant.