Navigation path

Themes
Agriculture & food
  Agriculture
  Animal health and welfare
  Food safety & health risks
  Forestry
  Marine resources & aquaculture
  Other
Energy
Environment
ERA-NET
Health & life sciences
Human resources & mobility
Industrial research
Information society
Innovation
International cooperation
Nanotechnology
Pure sciences
Research infrastructures
Research policy
Science & business
Science in society
Security
SMEs
Social sciences and humanities
Space
Special Collections
Transport

Countries
Countries
  Argentina
  Australia
  Austria
  Belarus
  Belgium
  Brazil
  Bulgaria
  Cameroon
  Canada
  China
  Colombia
  Croatia
  Cyprus
  Czech Republic
  Denmark
  Egypt
  Estonia
  Finland
  France
  Georgia
  Germany
  Ghana
  Greece
  Hungary
  Iceland
  India
  Ireland
  Israel
  Italy
  Japan
  Kazakhstan
  Kenya
  Korea
  Latvia
  Lithuania
  Luxembourg
  Malta
  Mexico
  Netherlands
  Nigeria
  Norway
  Peru
  Poland
  Portugal
  Romania
  Russia
  Senegal
  Serbia
  Slovakia
  Slovenia
  South Africa
  Spain
  Swaziland
  Sweden
  Switzerland
  Taiwan
  Tunisia
  Turkey
  Ukraine
  United Kingdom
  United States


   Headlines

Last Update: 31-08-2011  
Related category(ies):
Agriculture & food  |  Environment  |  Pure sciences

 

Add to PDF "basket"

Even low doses of insecticides put honeybees at risk

Scientists in France have discovered that honeybees are at a higher risk of dying from infection by Nosema ceranae (N. ceranae) when they are exposed to low doses of insecticides. The results, presented in the journal PLoS ONE, support the theory that combining more N. ceranae with a high pesticide content in beehives could contribute to colony depopulation.

Bee colonies have been plagued by a strange disease that causes the disappearance of thousands of colonies every year © Philippe Poirier and Cyril Vidau, courtesy CNRS
Bee colonies have been plagued by a strange disease that causes the disappearance of thousands of colonies every year
©  Philippe Poirier and Cyril Vidau, courtesy CNRS

Some 70 000 professional and amateur beekeepers work with honeybees (Apis mellifera) in France. Experts and laypersons recognise how important a role bees play in our environment, particularly on the sound functioning of the planet's ecosystems and agricultural productivity. But bee colonies have been dealing with a mysterious disease in recent years that triggers the disappearance of thousands of colonies each year. No one knows why this is happening.

A number of theories have emerged over time; some European and United States scientists postulate that losses of biodiversity and food resources, due to climate change, have intensified the problem. Others believe that a rise in single-crop farming and modification of landscapes, as well as pathogens causing diseases like foulbrood and varroasis are responsible for the problem.

Researchers say that while sufficient data exists on the effects of nutritional, parasitic and chemical stress on the health of honeybees, they cannot isolate any of these factors as being the single trigger in the decline of bee populations. Experts across the board agree that studies should spotlight the combined effects of several of the factors mentioned above.

Enter a team of researchers from the Laboratoire Microorganismes: Génome et Environnement (LMGE, CNRS/Université Blaise Pascal Clermont-Ferrand 2) and the Laboratoire de Toxicologie Environnementale (LTE, INRA Avignon) in France that assessed the effect of pathogen/toxin interactions on bee health.

The scientists chronically exposed newly emerged honeybees, of which some were healthy and others were infected with N. ceranae, to low doses of insecticides. According to them, the infected bees died when they were chronically exposed to insecticides. Sublethal doses did not protect those bees either.

The team points out that this combined effect on honeybee mortality was seen with daily exposure to extremely low loses (over 100 times less than the LD50 (Lethal Dose 50 = a dose that causes 50% mortality in a population) for each insecticide). The synergy is not contingent on the type of insecticide since the two active ingredients assessed in the study — fipronil and thiacloprid — are part of different groups. But experts have been unable to identify the mechanism that enables this synergy.

In this latest study, the researchers show how the interaction between Nosema disease and insecticides generates another risk for bee populations, and could be the missing link to helping us understand why an increasing number of bees are dying. The study also highlights how insecticide doses considered to be non-lethal have a lethal toxic potential for organisms that are infested with parasites, thus making bees a lot more vulnerable.

The results show that an improvement is needed in the management and protection of the bee population, according to the researchers.


Convert article(s) to PDF

No article selected


loading


Search articles

Notes:
To restrict search results to articles in the Information Centre, i.e. this site, use this search box rather than the one at the top of the page.

After searching, you can expand the results to include the whole Research and Innovation web site, or another section of it, or all Europa, afterwards without searching again.

Please note that new content may take a few days to be indexed by the search engine and therefore to appear in the results.

Print Version
Share this article
See also

PLoS ONE
Laboratoire Microorganismes: Génome et Environnement
'How honeybees avoid toxins in flower nectar'





  Top   Research Information Center