Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Neonicotinoid pesticides cause harm to honeybees

27.06.2016

Mainz researchers discover new mechanism associated with the worldwide decline of bee populations

One possible cause of the alarming bee mortality we are witnessing is the use of the very active systemic insecticides called neonicotinoids. A previously unknown and harmful effect of neonicotinoids has been identified by researchers at the Mainz University Medical Center and Goethe University Frankfurt.

They discovered that neonicotinoids in low and field-relevant concentrations reduce the concentration of acetylcholine in the royal jelly/larval food secreted by nurse bees. This signaling molecule is relevant for the development of the honeybee larvae. At higher doses, neonicotinoids also damage the so-called microchannels of the royal jelly gland in which acetylcholine is produced. The results of this research have been recently published in the eminent scientific journal PloS ONE.

"As early as 2013, the European Food Safety Authority published a report concluding that the neonicotinoid class of insecticides represented a risk to bees," said Professor Ignatz Wessler of the Institute of Pathology at the University Medical Center of Johannes Gutenberg University Mainz (JGU). "The undesirable effect of neonicotinoids now discovered is a further indication that these insecticides represent a clear hazard to bee populations and this is a factor that needs to be taken into account in the forthcoming reassessment of the environmental risks of this substance class."

Working in collaboration with Professor Bernd Grünewald of the Bee Research Institute at Goethe University Frankfurt, Professor Ignatz Wessler and his team uncovered this previously unknown damaging effect of neonicotinoids that impairs the development of honeybee larvae.

Wessler and Grünewald were able to directly demonstrate that neonicotinoids reduce the acetylcholine content of the larval food produced by nurse bees. Acetylcholine is a signaling molecule produced in the microchannels of the royal jelly gland of nurse bees. Comparable to neonicotinoids, it stimulates the nicotinic acetylcholine receptors that are also present in this gland.

"In lab tests we artificially removed acetylcholine from the larval food and the result was that bee larvae fed with this died earlier than bee larvae that received food containing acetylcholine," explained Wessler. In order to examine the effect of neonicotinoids on the acetylcholine content in the jelly in more detail, bee colonies were exposed to various concentrations of neonicotinoids in flight tunnels (clothianidin: 1, 10 and 100 µg/kg glucose solution; thiacloprid 200 and 8800 µg/kg).

"This exposure led to a reduction in the acetylcholine content of the jelly. Thus we were able to demonstrate that the field-relevant dose of the neonicotinoid agent thiacloprid (200 µg/kg) significantly reduces acetylcholine content by 50 percent. On exposure to higher doses, we were even able to verify that acetylcholine content can be reduced by 75 percent. Exposure of the bees with the higher doses results in serious damage to the microchannels and secretory cells of the jelly gland," emphasized Professor Ignatz Wessler. "Our research results thus confirm that the neonicotinoids can jeopardize the normal development of honeybee larvae."

The EU came to a similar conclusion back in December 2013 and imposed temporary restrictions on the use of three neonicotinoids, i.e., clothianidin, imidacloprid, and thiamethoxam. It had already been reported in several scientific publications that high but not lethal doses of various neonicotinoids could be associated with the falls in the populations of wild bees, bumblebees, and queen bees. Also reported were abnormalities in breeding activity and impaired flight orientation in the case of honeybees.

However, at the time there were critics of these reports who pointed out that, among other things, the researchers had used high, non-field-relevant doses of neonicotinoids and had carried out their experiments under artificial laboratory conditions. Moreover, the proponents of the use of neonicotinoids cited other possible causes of bee mortality, for example, the proliferation of the varroa mite and other pathogens.

Publication:
Wessler, I., Gärtner H.-A., Michel-Schmidt R., Brochhausen C., Schmitz L., Anspach L., Grünewald B., Kirkpatrick C.-J., Honeybees Produce Millimolar Concentrations of Non-neuronal Acetylcholine for Breeding: Possible Adverse Effects of Neonicotinoids. PLOSONE,
DOI: 10.1371/journal.pone.0156886

Contact:
Professor Dr. Ignatz Wessler
Institute of Pathology
Mainz University Medical Center
phone +49 6131 17-2824, e-mail: wessler@uni-mainz.de

Press contact:
Oliver Kreft, Press and Public Relations – Mainz University Medical Center,
phone +49 6131 17-7424, fax +49 6131 17-3496, e-mail: pr@unimedizin-mainz.de

Weitere Informationen:

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0156886

Petra Giegerich | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-mainz.de/

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>