New pesticides linked to bee population collapse

Two studies confirm dangers of 'nerve agents' used on one-third of all British cropland

A A A

Worldwide declines in bee colonies, threatening much of global agriculture, may be caused by a new generation of nerve-agent pesticides, two new scientific studies strongly suggest. The findings place a massive question mark over the increasingly controversial compounds, now the fastest growing family of insecticides in the world.

Silent menace graphic: The threat to bees

 

Bee declines represent a serious threat to agriculture because bees are the pollinators of a large percentage of crops. Both honey bees and wild bumble bees are seriously harmed by exposure to neonicotinoid insecticides, even by tiny doses not sufficient to kill them outright, the studies by British and French scientists report today.

The British study, carried out by scientists from the University of Stirling, concludes that "there is an urgent need to develop alternatives to the widespread use of neonicotinoid pesticides on flowering crops wherever possible".

About 30 per cent of British cropland – 3.14 million acres – was being treated with the chemicals in 2010, while in the US the figures for neonicotinoid use are enormous: in 2010, 88 million acres of maize, 77 million acres of soy and 53 million acres of wheat were treated with them. The compounds, which attack insects' central nervous systems, have been increasingly implicated in the widespread decline of honey bees and wild bees over the past decade, which have culminated in the mysterious colony collapse disorder in the US – a phenomenon in which the whole population of a beehive suddenly vanishes.

The value of bees' pollination services has been estimated at £200m per year just in Britain. The global annual value of pollination has been estimated at £128bn annually.

Many beekeepers have become convinced that the new pesticides are behind the declines, and in France, Italy and other countries they have been banned. But in Britain and the US their use continues.

Last year The Independent revealed that the American government's own chief bee researcher, Dr Jeffrey Pettis of the US Department of Agriculture, had conducted a study showing that bees exposed to microscopic doses of neonicotinoids were much more vulnerable to disease – but his study had not been published nearly two years after it was completed. Dr Pettis's findings were eventually published two months ago and were described by The Economist as "a plausible hypothesis for the cause of colony collapse disorder".

The findings of the two new studies, published simultaneously in the journal Science, are explosive.

The British study, led by Stirling's Professor David Goulson, showed that growth of colonies of the common buff-tailed bumble bee, Bombus terrestris, slowed after the insects were exposed to "field-realistic levels" of imidacloprid, a common neonicotinoid insecticide. The production of queens, essential for colonies to continue, declined by a massive 85 per cent in comparison with unexposed colonies used as controls.

"Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact on wild bumble bee populations across the developed world," the Stirling team says.

The French study, led by Mikaël Henry from France's National Institute for Agronomic Research in Avignon, looked at honey bees exposed to another neonicotinoid product, thiamethoxam.

The study found that even though the dose was sub-lethal, the exposure seriously affected the bees' homing abilities to the extent that they proved to be two to three times more likely to die while away from their nests than untreated bees. "Non-lethal exposure... causes high mortality due to homing failure, at levels that could put a colony at risk of collapse," the researchers say.

"These new studies put beyond all reasonable doubt the capacity for neonicotinoids to cause environmental destruction," said Matt Shardlow, director of Buglife, the invertebrate conservation trust. "Our Government must take the precautionary step of banning their use." The Government has twice been formally asked to suspend neonicotinoids; on both occasions the requests were ignored.

The problem posed by neonicotinoids is that they are "systemic" pesticides, which means that they do not just sit on the surface of the plant, but are taken up into every part of it, including the pollen and the nectar; and so even if bees are not the target species, they ingest the chemicals through the pollen and nectar when they are foraging.

Force of nature: The life of bees

Bumble bees are distinctive for their large, furry appearance. They are hugely important as natural crop pollinators. The queen is the only individual that can survive the winter, hibernating underground and emerging in spring to build a nest.

She lays eggs which hatch as worker bees. The workers fly from flower to flower gathering nectar and spreading pollen as they go. Bumble bees pollinate a great variety of plants – both wild and agricultural.

Honey bees have a different life cycle, with all the bees surviving the winter inside the hive. Honey bees are much better than bumble bees at producing honey, made from the nectar and sweet deposits of trees and plants brought back to the hive. It is these bees that are bred by beekeepers all over the world.

Both honey bee and bumble bee populations have dramatically declined in recent decades. In Britain, bumble bees have been vanishing since the 1950s. A UN report last year said that a phenomenon known as Colony Collapse Disorder that had seen the number of honey bee colonies in Europe and the USA plummet since the 1960s, had become a global problem, with beekeepers in Japan and Egypt all reporting losses of their colonies.

Arts and Entertainment
filmPoldark production team claims innocence of viewers' ab frenzy
Life and Style
Google marks the 81st anniversary of the Loch Ness Monster's most famous photograph
techIt's the 81st anniversary of THAT iconic photograph
News
Katie Hopkins makes a living out of courting controversy
people
News
General Election
Have you tried new the Independent Digital Edition apps?
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Office Administrator

£14000 - £18000 per annum: Recruitment Genius: An Office Administrator is requ...

Recruitment Genius: Sales Executive - Commercial Vehicles - OTE £40,000

£12000 - £40000 per annum: Recruitment Genius: Due to expansion and growth of ...

Ashdown Group: Senior PHP Developer - Sheffield - £50,000

£40000 - £50000 per annum: Ashdown Group: Senior PHP Developer position with a...

Recruitment Genius: Operations Leader - Plasma Processing

Negotiable: Recruitment Genius: An Operations Leader is required to join a lea...

Day In a Page

Revealed: Why Mohammed Emwazi chose the 'safe option' of fighting for Isis, rather than following his friends to al-Shabaab in Somalia

Why Mohammed Emwazi chose Isis

His friends were betrayed and killed by al-Shabaab
'The solution can never be to impassively watch on while desperate people drown'
An open letter to David Cameron: Building fortress Europe has had deadly results

Open letter to David Cameron

Building the walls of fortress Europe has had deadly results
Tory candidates' tweets not as 'spontaneous' as they seem - you don't say!

You don't say!

Tory candidates' election tweets not as 'spontaneous' as they appear
Mubi: Netflix for people who want to stop just watching trash

So what is Mubi?

Netflix for people who want to stop just watching trash all the time
The impossible job: how to follow Kevin Spacey?

The hardest job in theatre?

How to follow Kevin Spacey
Armenian genocide: To continue to deny the truth of this mass human cruelty is close to a criminal lie

Armenian genocide and the 'good Turks'

To continue to deny the truth of this mass human cruelty is close to a criminal lie
Lou Reed: The truth about the singer's upbringing beyond the biographers' and memoirists' myths

'Lou needed care, but what he got was ECT'

The truth about the singer's upbringing beyond
Migrant boat disaster: This human tragedy has been brewing for four years and EU states can't say they were not warned

This human tragedy has been brewing for years

EU states can't say they were not warned
Women's sportswear: From tackling a marathon to a jog in the park, the right kit can help

Women's sportswear

From tackling a marathon to a jog in the park, the right kit can help
Hillary Clinton's outfits will be as important as her policies in her presidential bid

Clinton's clothes

Like it or not, her outfits will be as important as her policies
NHS struggling to monitor the safety and efficacy of its services outsourced to private providers

Who's monitoring the outsourced NHS services?

A report finds that private firms are not being properly assessed for their quality of care
Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

Zac Goldsmith: 'I'll trigger a by-election over Heathrow'

The Tory MP said he did not want to stand again unless his party's manifesto ruled out a third runway. But he's doing so. Watch this space
How do Greek voters feel about Syriza's backtracking on its anti-austerity pledge?

How do Greeks feel about Syriza?

Five voters from different backgrounds tell us what they expect from Syriza's charismatic leader Alexis Tsipras
From Iraq to Libya and Syria: The wars that come back to haunt us

The wars that come back to haunt us

David Cameron should not escape blame for his role in conflicts that are still raging, argues Patrick Cockburn
Sam Baker and Lauren Laverne: Too busy to surf? Head to The Pool

Too busy to surf? Head to The Pool

A new website is trying to declutter the internet to help busy women. Holly Williams meets the founders