Vinegar flies should normally try to avoid their sick conspecifics to prevent becoming infected themselves. Nevertheless, as researchers from the Max Planck Institute for Chemical Ecology and Cornell University recently found out, they are irresistibly attracted to the smell given off by sick flies. A dramatic increase in the production of the sex pheromones responsible for the attractive odor of the infected flies is caused by pathogens: this perfidious strategy is used by the deadly germs to enable them to infect healthy flies and spread even further (Nature Communications, August 16, 2017)
Markus Knaden and Bill Hansson, and their colleagues at the Department of Evolutionary Neuroethology, study ecologically relevant odors in the natural environment of insects, especially vinegar flies. In this new study they focused on a deadly smell: the odor of conspecifics which have a lethal bacterial infection.
Mating experiments with Drosophila melanogaster: Enhanced sexual attractiveness of sick flies does not lead to reproductive success. Increased pheromone production benefits only the pathogens.
“We had originally hoped to find a dedicated neuronal circuit in the flies which is specialized to detect and avoid sickness odors. Instead we observed that healthy flies were especially attracted to the smell of infected ones. When we realized that flies cannot avoid becoming infected, as sick flies produce particularly high amounts of pheromones, we were surprised but found that even more interesting,” says Markus Knaden, one of the leaders of the study.
State-of-the-art analytical methods enabled the researchers to identify and quantify the odors of single flies. Vinegar flies which suffered from bacterial infection and their feces emitted dramatically increased amounts of the typical odors that attract other flies. The hypothesis that last-minute pheromone emission by sick insects would enhance their reproductive success turned out to be wrong, as mating assays demonstrated that sick flies were barely able to copulate.
Insect immunologist Nicolas Buchon from Cornell University and his team, who were also involved in the study, noticed that the increase in pheromone production matched the up-regulation of certain immune responses in the flies.
Ian Keesey, the first author of the study, and his colleagues in Jena therefore tested mutant flies which lacked the ability to produce these responses and found that these flies emitted far fewer pheromones when they became infected in comparison to sick wild-type flies. Further analysis of the insects’ metabolism convinced the researchers that ongoing bacterial growth and the subsequent damages caused by the pathogens are necessary to induce increases in pheromone production.
The scientists observed similar results when they conducted experiments with other fly species. Seven other Drosophila species as well as the yellow fever mosquito Aedes aegyptii conspecifics dramatically changed their olfactory profile after infection with the pathogen. Manipulation of social communication in insects by pathogenic bacteria seems to be a more general phenomenon in nature than thought.
Markus Knaden hopes that the new insights can one day contribute to useful applications: “A well-established method to combat insect-transmitted diseases and to control agricultural pest insects is the use of pheromone traps. By infecting insects with bacteria we could generally increase their pheromone emission. This could enable us to identify novel pheromones in species that have not been investigated so far.” [AO/KG/EW]
Keesey, I. W., Koerte, S., Khallaf, M. A., Retzke, T., Guillou, A., Grosse-Wilde, E., Buchon, N., Knaden, M., Hansson, B. S. (2017). Pathogenic bacteria enhance dispersal through alteration of Drosophila social communication. Nature Communications
Prof. Dr. Bill S. Hansson, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-1401, E-Mail firstname.lastname@example.org
Dr. Markus Knaden, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-1421, E-Mail email@example.com
Contact and Media Requests:
Angela Overmeyer M.A., Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07743 Jena, +49 3641 57-2110, E-Mail firstname.lastname@example.org
Download high-resolution images via http://www.ice.mpg.de/ext/downloads2017.html
http://www.ice.mpg.de/ext/index.php?id=evolutionary-neuroethology&L=0 Department of Evolutionary Neuroethology
Angela Overmeyer | Max-Planck-Institut für chemische Ökologie
More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Life Sciences
19.01.2018 | Life Sciences
19.01.2018 | Physics and Astronomy