Pollination under threat as bees vanish

Another life'If the bee disappeared off the surface of the globe then man would only have four years of life left. No more bees, no more pollination, no more plants, no more animals, no more man."

He undoubtedly never said it - Albert Einstein had neither expertise in biology nor a taste for hyperbole - but his "quote" has been given a fresh outing in the media this spring with news of a mounting honeybee disaster in Europe and America.

In the United States, reportedly, about half the nation's hives have died off since November. In what has now been termed Colony Collapse Disorder (CCD) the adult bees have departed without leaving a trace and abandoning capped brood (infant bees) and ample food stores. If not quite in the same way, many thousands more colonies have collapsed in Spain, and there have been further heavy losses as far east as Poland. Two-thirds of London's colonies, it seems, did not survive the winter. In Ireland, Teagasc scientists wait to see if CCD will add to existing problems in keeping colonies healthy for Ireland's 3,000 beekeepers.

The strains of bee in their hives have long been separated from their Asian origins and have lost the original, native tolerance of particular parasites. One of these, a bloodsucking mite called varroa, emerged as a damaging plague in Europe in about 1970 and travelled on to America through the trade in queen bees. It was reckoned that a quarter of North America's wild and domesticated honeybees disappeared in the 1990s and costs to American farmers (growing almonds intensively in California, for example) were heading for $6 million (€4,472,100) a year.

Varroa was first detected in Ireland in Sligo in 1998 and has since spread to most parts of the island, leaving weakened colonies increasingly vulnerable to viral diseases. Managing varroa and its complications is an ongoing task for Teagasc. If CCD arrives in force, its research will be handicapped by a simple lack of bodies: the departing bees leave mere traces of their DNA for scientists.

The disease, or syndrome of ills, may not be so new after all, despite the theories of contemporary causes, including stray genes from GM crops and disorienting mobile phone signals. A "Disappearing Disease" of honeybees has been an intermittent puzzle to US beekeepers for decades. Even a new mutation of Nosema, a parasitic microbe, proposed by one leading US researcher, reaches back to problems of a century ago.

Whatever its cause or true extent, CCD contributes to a real and troubling phenomenon; even Teagasc readily quotes a "pollination crisis".

It is true that whatever happens to the honeybee, no Irish wildflower or wild fruiting bush or tree is likely to die out for lack of pollination: bumblebees, flies, moths, beetles, wasps and butterflies are all effective pollinators of the countryside and its crops. Without the honeybee, some intensive commercial crops would suffer but the rest of our plant life would be virtually undisturbed.

The loss of bees as a whole would be a very different matter, which is why there is so much concern about the fortunes of Ireland's 102 wild species. Most of these lead solitary lives, but 19 are the familiar social bumblebees, breeding seasonal teams of tireless workers. More than half these species are in decline, especially among those that emerge late in the spring. Yet the only insect protected by law in the Republic is the scarce marsh fritillary butterfly; a few more butterflies are added in Northern Ireland.

The switch from hay meadows to silage and the urbanisation of eastern Ireland has forced most Irish bees to retreat to the west - a phenomenon mapped in lengthy field research led by scientists from Trinity College, Dublin, and Queen's University, Belfast.

Their concern to make people aware of the bees and their importance has prompted a first-rate booklet, The State of Ireland's Bees, which has been distributed to schools across the island, and a very browsable website, www.tcd.ie/zoology/research/bees.

Teagasc, meanwhile, is alert to a potential new threat to Ireland's native bumblebees: the imports of packages of Continental bees by growers using greenhouses and tunnels to raise early strawberries, peppers and tomatoes. Cardboard "hives" of perhaps 50 Bombus terrestris, among the biggest species of bumblebee, are supplied by breeders, some of whom may use stock from the Balkans and Greece where bees become active earlier in the year.

Escaping from their Irish workplaces, the bees could bring in new diseases. They could also hybridise with our native bumblebees, to the detriment of their gene pool. Teagasc researchers are now sampling the DNA of Bombus terrestris across Europe to see how distinctive and worth conserving this island's sub-species of the bee really is.

Eye on nature

Walking in the Wicklow hills, I was amazed to see dozens of dead bees scattered around the trail, covering an area of 20ft or 30ft. Some of them were only heads and some just the lower part of the body. T Curtis, Fitzwilliam Quay, Dublin 4

I have watched a pair of mistle thrushes, since mid-April, build a nest in the fork of a hawthorn tree, sit for ages, and finally hatch out their babies. Today, as they attempted to feed them, a hen blackbird kept attacking them, sending them off, and she then went in to feed them. She kept a lookout as she searched for food on the ground under the tree, then as soon as the thrushes came on to the nest she flew up and attacked them. If she was on the nest when the thrushes came back, they would attack her. Is it possible that the blackbird laid eggs in the thrushes' nest? I only ever saw the thrush sitting on the eggs. Jane Dunn, Bonniconlan, Co Mayo

It is possible that the blackbird lost her mate and her nest and took over the mistle thrushes' nest in compensation. Both birds tend to choose similar nesting sites.