Double dose of pesticide poses new danger for bumblebees

Government study suggests long-term exposure to chemicals can destroy colonies

A A A

The combination of two pesticides commonly used on UK fields can have damaging effects on the behaviour of bumblebees and cause their colonies to collapse, new research by British scientists has found.

And long-term exposure to individual pesticides – for up to a month – is also likely to have damaging effects, the scientists say. They argue that current safety tests are insufficient, as guidelines only demand pesticides are tested on bees for four days.

The findings, which come from a Government-funded study, represent the fifth major piece of research to appear this year linking the worldwide and worrying declines of bees to pesticides, and in particular to the use of the relatively new nerve-agent pesticides, the neonicotinoids.

This new study is considered particularly important because bees forage widely so are likely to encounter more than one type of pesticide.

The research was carried out at Royal Holloway College, University of London, as part of the Insect Pollinators Initiative, a £10m British programme looking at threats to pollinating insects such as bees, butterflies, moths and hoverflies.

Published last night in Nature online, the study reports that exposure to two commonly used pesticides, one a neonicotinoid and the other from a different pesticide family, a pyrethroid, at concentrations approximating what might be found in the field, impaired the natural foraging behaviour of bumblebees. This led to increased numbers of deaths and in some cases the failure of colonies. The compounds involved were made by major agrochemical manufacturers: the most widely used neonicotinoid, imidacloprid, manufactured by Bayer and already implicated in problems with bees in earlier studies, was one, while the pyrethroid was lambda-cyhalothrin, originally developed by Syngenta.

The Royal Holloway researchers found that bees exposed over a month to imidacloprid were less able to collect pollen effectively, which meant that their colonies had less food available and so could not raise as many workers. On average, the percentage of workers leaving the colony and then getting lost was 55 per cent higher in those receiving imidacloprid than those that were not exposed to pesticides.

Two of the test colonies that were exposed to both pesticides together collapsed completely.

"The risk of exposure to multiple pesticides, or of the same pesticides being applied to different (adjacent) crops, is currently not considered when evaluating the safety of pesticides for bees," the researchers say.

On long-term effects, they say: "Considering that we did not detect significant effects until two to four weeks into our study, the current... guideline of a maximum exposure of 96 hours for testing acute effects of pesticides on honeybees appears to be insufficient."

A spokesman for Syngenta said yesterday: "There's no evidence that pesticides damage the health of bee populations but yet again we see unrealistic research being used to prove the opposite."

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Ashdown Group: Junior Reports Developer / Application Support Engineer

£23000 - £30000 per annum + pension, 25days holiday: Ashdown Group: An industr...

Ashdown Group: BI/ SSRS Developer

£40000 per annum + pension, 25days holiday: Ashdown Group: An experienced BI/ ...

Recruitment Genius: Ecommerce Sales Executive

£18000 - £30000 per annum: Recruitment Genius: A highly successful e-commerce ...

Recruitment Genius: Marketing Manager

£17000 - £19000 per annum: Recruitment Genius: An experienced marketeer is req...

Day In a Page

Homeless Veterans appeal: 'You look for someone who's an inspiration and try to be like them'

Homeless Veterans appeal

In 2010, Sgt Gary Jamieson stepped on an IED in Afghanistan and lost his legs and an arm. He reveals what, and who, helped him to make a remarkable recovery
Could cannabis oil reverse the effects of cancer?

Could cannabis oil reverse effects of cancer?

As a film following six patients receiving the controversial treatment is released, Kate Hilpern uncovers a very slippery issue
The Interview movie review: You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here

The Interview movie review

You can't see Seth Rogen and James Franco's Kim Jong Un assassination film, but you can read about it here
Serial mania has propelled podcasts into the cultural mainstream

How podcasts became mainstream

People have consumed gripping armchair investigation Serial with a relish typically reserved for box-set binges
Jesus Christ has become an unlikely pin-up for hipster marketing companies

Jesus Christ has become an unlikely pin-up

Kevin Lee Light, aka "Jesus", is the newest client of creative agency Mother while rival agency Anomaly has launched Sexy Jesus, depicting the Messiah in a series of Athena-style poses
Rosetta space mission voted most important scientific breakthrough of 2014

A memorable year for science – if not for mice

The most important scientific breakthroughs of 2014
Christmas cocktails to make you merry: From eggnog to Brown Betty and Rum Bumpo

Christmas cocktails to make you merry

Mulled wine is an essential seasonal treat. But now drinkers are rediscovering other traditional festive tipples. Angela Clutton raises a glass to Christmas cocktails
5 best activity trackers

Fitness technology: 5 best activity trackers

Up the ante in your regimen and change the habits of a lifetime with this wearable tech
Paul Scholes column: It's a little-known fact, but I have played one of the seven dwarves

Paul Scholes column

It's a little-known fact, but I have played one of the seven dwarves
Fifa's travelling circus once again steals limelight from real stars

Fifa's travelling circus once again steals limelight from real stars

Club World Cup kicked into the long grass by the continued farce surrounding Blatter, Garcia, Russia and Qatar
Frank Warren column: 2014 – boxing is back and winning new fans

Frank Warren: Boxing is back and winning new fans

2014 proves it's now one of sport's biggest hitters again
Jeb Bush vs Hillary Clinton: The power dynamics of the two first families

Jeb Bush vs Hillary Clinton

Karen Tumulty explores the power dynamics of the two first families
Stockholm is rivalling Silicon Valley with a hotbed of technology start-ups

Stockholm is rivalling Silicon Valley

The Swedish capital is home to two of the most popular video games in the world, as well as thousands of technology start-ups worth hundreds of millions of pounds – and it's all happened since 2009
Did Japanese workers really get their symbols mixed up and display Santa on a crucifix?

Crucified Santa: Urban myth refuses to die

The story goes that Japanese store workers created a life-size effigy of a smiling "Father Kurisumasu" attached to a facsimile of Our Lord's final instrument of torture
Jennifer Saunders and Kate Moss join David Walliams on set for TV adaptation of The Boy in the Dress

The Boy in the Dress: On set with the stars

Walliams' story about a boy who goes to school in a dress will be shown this Christmas