Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study finds higher pathogen loads in collapsed honeybee colonies

18.08.2009
Honeybees in colonies affected by colony collapse disorder (CCD) have higher levels of pathogens and are co-infected with a greater number of pathogens than their non-CCD counterparts, but no individual pathogen can be singled out as the cause of CCD, according to a study by an international team of researchers.

The researchers, who represented Penn State's College of Agricultural Sciences, University of Liege, Gembloux Agricultural University, North Carolina State University and the U.S. Department of Agriculture's Agricultural Research Service (ARS), collected samples of adult bees, wax comb, pollen and brood – developing larvae – from 91 colonies in 13 apiaries in Florida and California and quantified more than 200 variables, including the presence of parasites such as varroa and tracheal mites; infection by bacteria, viruses and fungi; pesticide levels; nutritional factors; and bee physiology. No single factor was found consistently only in those colonies suffering from CCD.

The study's findings, which were published in the online journal PLoS ONE, illustrate the complexity of solving the CCD problem, according to lead author and Penn State entomologist Dennis vanEngelsdorp. "Our results suggest that this condition may be contagious or the result of exposure to a common risk factor that impairs the bees' immune systems, making them more susceptible to pathogens," said vanEngelsdorp, who also is acting state apiarist for the Pennsylvania Department of Agriculture.

VanEngelsdorp noted that higher pathogen loads are likely to have caused CCD symptoms, but what causes the bees to become infected with so many pathogens is still not known. "Although pathogens seem likely to play a critical role in CCD, that role may be secondary, much like AIDS patients die from secondary diseases," he added.

No one of the screened pathogens had a higher prevalence in colonies that had CCD. There also was no significant difference in the prevalence nor in the total load of varroa or tracheal mites and Nosema, a protozoan that causes disease in bees.

But overall, CCD colonies were co-infected with a greater number of pathogens -- viruses, bacteria and microparasites such as Nosema. For instance, 55 percent of CCD colonies were infected with three or more viruses compared to 28 percent of non-CCD colonies.

The researchers also found detectable levels of residues from 50 different pesticides in all of the sampled colonies, but there was no association between increased pesticide levels and CCD.

In fact, the pyrethroid insecticide Esfenvalerate -- used for a wide variety of pests such as moths, flies, beetles and other insects on vegetable, fruit and nut crops -- was more prevalent in the wax in non-CCD colonies, being found in 32 percent of non-CCD colonies compared to 5 percent of the CCD colonies.

Coumaphos, which is used to treat varroa mites in honeybees, also was found in higher levels in non-CCD colonies.

Entomologist Jeff Pettis with the ARS Bee Research Laboratory in Beltsville, Md., said the study suggests that future research should focus on monitoring parasite, pathogen and pesticide loads, as well as potential interactions among pesticide and pathogen loads. "While the study's results don't indicate a specific cause of CCD, the results do help scientists narrow the direction of future CCD research by showing that some possible causes are less likely," said Pettis.

Study co-authors from Penn State are included Chris Mullin, professor of entomology; Maryann Frazier, senior extension associate in entomology; Jim Frazier, professor of entomology; and Diana Cox-Foster, professor of entomology and Robyn Underwood.

Other researchers included Jay D. Evans and Yanping Chen, ARS; Claude Saegerman, University of Liege; Eric Haubruge and Bach Kim Nguyen, Gembloux Agricultural University, Belgium and David R. Tarpy, North Carolina State University.

Chuck Gill | EurekAlert!
Further information:
http://www.psu.edu

More articles from Agricultural and Forestry Science:

nachricht Energy crop production on conservation lands may not boost greenhouse gases
13.03.2017 | Penn State

nachricht How nature creates forest diversity
07.03.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>