In the summer season, a hive includes up to 50,000 workers, several hundred drones and one queen, living in very close surroundings in a warm and humid atmosphere, which is also conducive to the growth of pathogenic bacteria. This might lead you to believe that infections spread easily in a bee hive.
Varroa mite females suck at two bee pupae, a drone pupa (left) and a worker pupa (right). The mites are only about one millimeter in size. Photo: Helga R. Heilmann
However, the bees are well protected against this risk. Firstly, they set great store on hive hygiene. Furthermore, young workers, drones and queens react to bacterial infections with several defense mechanisms of their innate immune system. Bee larvae are also capable of defending themselves effectively against bacteria. All this has been demonstrated in recent years by the Beegroup of Professor Jürgen Tautz at the Biocenter of the University of Würzburg.
Bacteria kill off bee pupae quickly
Still, the insects are defenseless at a certain stage of their development: After pupation of the larvae, their immune system stays completely inactive. This is reported in the journal PLOS ONE by the Würzburg scientists. When bee pupae were exposed to "harmless" Escherichia coli bacteria, this led to their death within only a few hours of infection. "The bacteria proliferated rapidly in the pupae, which apparently caused the death of the latter," says Professor Hildburg Beier, a member of the Beegroup.
In an intact bee hive, the pupae are usually well protected from bacterial infection. They develop in sealed brood combs, which are largely sterile. This is why the insects omit to protect themselves with immune reactions at this life stage. "This is biologically reasonable, because anything else would be quite a waste of energy and material," says Beier. After all, the developmental processes taking place in the cocoon are demanding enough.
Do Varroa mites carry bacteria?
The lack of immune responses during the time of pupation might spell doom for the European honey bees. This is due to the Varroa mite (Varroa destructor), a parasite that was introduced from Asia about three decades ago. "The mite is capable of wiping out entire bee colonies, because it transfers pathogenic viruses to the adult insects – as suggested previously," explains Professor Tautz, who is a beekeeper himself.
However, it is now conceivable that the mites pose a danger to the bees in yet another way: The female parasites penetrate into the brood cells and suck at the pupae. It cannot be excluded that they thereby transfer otherwise quite harmless bacteria to the pupae. This would certainly prove fatal to the pupae as the recent experiments of the Beegroup have shown.
Careful control of the parasites necessary
According to the researchers, there is reason to fear that the Varroa mite poses a far greater threat to bees than previously thought. Therefore, we are faced with the permanent and increasingly demanding task to ensure a careful and comprehensive control of this parasite in order to protect our honey bee populations.
"Antibacterial Immune Competence of Honey Bees (Apis mellifera) Is Adapted to Different Life Stages and Environmental Risks", Heike Gätschenberger, Klara Azzami, Jürgen Tautz, Hildburg Beier (2013), PLoS ONE 8(6): e66415. doi:10.1371/journal.pone.0066415
Go to the article in PLOS ONE: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0066415
Prof. Dr. Hildburg Beier, Biocenter at the University of Würzburg, T +49 (0)931 31-84201, firstname.lastname@example.org
Robert Emmerich | Uni Würzburg
Don't Give the Slightest Chance to Toxic Elements in Medicinal Products
23.03.2018 | Physikalisch-Technische Bundesanstalt (PTB)
North and South Cooperation to Combat Tuberculosis
22.03.2018 | Universität Zürich
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy