Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Their enemy’s sex pheromone helps flies protect their offspring

17.12.2015

Female Drosophila flies avoid oviposition sites that smell of parasitic wasps. This increases the survival rate of their larvae.

Females of the vinegar fly Drosophila melanogaster show an especially strong response to the odor of their most dangerous enemies, parasitic wasps of the genus Leptopilina. In nature, up to 80 percent of Drosophila larvae are parasitized by these wasps, which lay their eggs into the larvae.


A parasitic wasp (Leptopilina boulardi) lays its eggs into larvae of the vinegar fly Drosophila melanogaster. In nature, many Drosophila larvae are killed this way.

Markus Knaden / Max Planck Institute for Chemical Ecology

The wasps’ larvae grow and consume the Drosophila larvae from within. However, an innate early warning system alerts female flies when wasps are near and thus increases the chance the flies’ offspring will survive.

Researchers at the Max Planck Institute for Chemical Ecology identified the olfactory neuron in Drosophila which senses if enemies are nearby by recognizing their odors.

The chemical compounds in the wasps trigger avoidance behavior in the flies. One of the compounds is the wasps’ sex pheromone. For the first time scientists have described an olfactory circuit entirely dedicated to the detection of a fatal enemy. (PLoS Biology, December 2015)

When different organisms share the same habitat in nature, their interactions are often reduced to either eating or being eaten. In the course of evolution, organisms have evolved different adaptations in order to ensure their survival or to increase the survival rate of their offspring. Insects’ highly sensitive and highly specialized sense of smell plays a crucial role in many of their complex survival strategies.

Together with international partners, scientists from the Department of Evolutionary Neuroethology led by Bill Hansson and Markus Knaden found that the vinegar fly Drosophila melanogaster houses an olfactory neuron which is entirely dedicated to detecting the sex pheromone of parasitic wasps.

A combination of gas-chromatographic and electrophysiological analyses as well as behavioral assays with flies and larvae led to the results. By applying these methods, the scientists could identify both the wasp odors and the olfactory receptors in Drosophila which detected them. Last but not least, they were able to demonstrate that the perception of these odors influenced the flies’ behavior: Adult flies as well as their larvae actively avoided the smell of parasitic wasps.

Three components of the wasps’ odor activate a single olfactory neuron on the antennae of adult Drosophila flies. Chemical analysis revealed that these three substances are actinidine, nepatalctol, and iridomyrmecin. Interestingly, iridomyrmecin is the sex pheromone of the female Leptopilina wasp. Although adult flies have two olfactory receptors and smell all three substances in the wasps’ odor, Drosophila larvae lack one of the two receptors; they smell only the sex pheromone iridomyrmecin.

The results show again how highly specific individual olfactory receptors in Drosophila can be. In previous experiments, the researchers tested all receptors by stimulating them with different scents. However, there were a few receptors that could not be activated. Assuming that these receptors were highly specific and associated with odors that are important for the flies’ survival in nature, the scientists performed behavioral assays and tested the odor of parasitic wasps.

“Until recently, scientists thought that most odors were detected by several receptors and that each receptor was stimulated by numerous different smells. The activation patterns of the different receptors would tell the fly which environmental odors were present.

However, the results from our lab tell a completely different story: At least parts of the olfactory system are highly specific. Odors that are of particular importance for the fly are not detected and processed by the general system; each of these odors has its own channel. Seemingly, this has the effect that the detection of dangerous bacteria (geosmin) or the best oviposition sites (limonene) cannot be interfered with by other environmental odors,” says Markus Knaden, who led the study together with Bill Hansson.

The strength of this study is that it combines several lines of evidence − chemical and physiological analyses, and behavioral experiments with flies and larvae. The researchers suggest that vinegar flies learned to use the odor of the parasites for their own advantage in the course of evolution.

This strategy, which has evolved as a means of self-protection, is astonishing, especially since avoidance of the wasp odor is innate, as experiments using flies that had never been close to parasitic wasps and did not know the scent of Leptopilina showed. Furthermore, four Drosophila species demonstrated the same avoidance behavior when they encountered the scent of Leptopilina wasps.

That vinegar flies avoid their enemies by using their sex pheromone as an olfactory cue is a very clever move in a game called co-evolution. A counter-adaptation by the wasps is difficult, because the release of this pheromone is indispensable for reproduction. [AO]

Original Publication:
Ebrahim, S. A. M., Dweck, H. K. M., Stökl, J., Hofferberth, J. E., Trona, F., Weniger, K., Rybak, J., Seki, Y., Stensmyr, M. C., Sachse, S., Hansson, B. S., Knaden, M. (2015). Drosophila avoids parasitoids by sensing their semiochemicals via a dedicated olfactory circuit. PLoS Biology. DOI: 10.1371/journal.pbio.1002318
http://dx.doi.org/10.1371/journal.pbio.1002318

Further Information:
Dr. Markus Knaden, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany, Tel. +49 3641 57-1421, E-Mail mknaden@ice.mpg.de

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 overmeyer@ice.mpg.de

Download high-resolution images via http://www.ice.mpg.de/ext/downloads2015.html

Weitere Informationen:

http://www.ice.mpg.de/ext/evolutionary-neuroethology.html (Department of Evolutionary Neuroethology)
http://www.ice.mpg.de/ext/971.html ("A direct line through the brain to avoid rotten food – a full STOP signal for Drosophila", press release, December 7, 2012)
http://www.ice.mpg.de/ext/1052.html ("Preference for Oranges Protects Fruit Flies from Parasites", press release, December 5, 2013)

Angela Overmeyer | Max-Planck-Institut für chemische Ökologie

Further reports about: Drosophila Max-Planck-Institut flies fly larvae parasitic parasitic wasps sex pheromone vinegar Ökologie

More articles from Life Sciences:

nachricht Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>