Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Orchid Tricks Hoverflies

15.10.2010
Eastern marsh helleborine mimics aphid alarm pheromones to attract pollinators
Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, have discovered the trick the orchid Epipactis veratrifolia uses to attract pollinating hoverflies.

The plant’s flower practices a very special mimicry: It produces three chemical substances that are usually emitted as alarm pheromones among aphids. Hoverfly females smell the alarm and lay their eggs close to the aphids, which are the perfect baby food for their hatching larvae.


Eastern marsh helleborine (Epipactis veratrifolia), an orchid species, has successfully lured a hoverfly of the genus Ischiodon by mimicking alarm pheromones usually emitted by aphids. MPI Chemical Ecology, Johannes Stökl

By mimicking these alarm pheromones, the orchid takes advantage of the hoverfly females, deceiving them into pollinating its flower. The flies even lay their eggs on the flower. However, the hatching larvae are doomed, because no aphids are available in the orchid flower. (Proceedings of the Royal Society B, October 13, 2010)

Beautiful but cunning

Even Darwin was a self-admitted orchid lover. Dictionaries describe orchids as exotic ornamentals. Indeed, these plants – more than 30000 different species are thought to exist – are exotic due their extraordinary and diverse flower morphology. However, they are also exotic from a point of view other than beauty: as crafty imposters in order to achieve reproduction and to make sure that their ovaries are pollinated. Orchids depend on the assistance of pollinators, and like many other flowering plants, attract insects.

Epipactis veratrifolia, an orchid native in South Turkey, the Middle East, and Cyprus, has specialized in hoverflies. Because these insects prefer aphids as food for their larvae, the orchid produces three aphid alarm substances, α- and β-pinene, and β-myrcene and β-phellandrene, all of which attract hoverfly females. Interestingly, as the scientists observed, even male hoverflies hang around the orchids, hoping for a chance to copulate with the attracted females.

A bit of nectar as reward

“Hoverfly females as well as males enjoy the small amount of nectar the orchid flower provides. Both sexes serve as pollen transmitters,” says ecologist Johannes Stökl. The alarm substances lure five of the different hoverfly species that feed on aphids. Females lay all their eggs in the flower of the orchid, although no aphids are there. “We assume that the insects are not only deceived by the aphid alarm pheromones, but also fall for the aphid-like dark warts in the orchid’s flower,” explains Bill Hansson, director at the Max Planck Institute.

Mass spectra and electroantennograms

The aphid species Megoura viciae preferred by Episyrphus balteatus hoverflies produces α- and β-pinene as well as β-myrcene. These volatile substances generate measurable electrical impulses in the hoverfly antennae. Behavioral experiments carried out by the research team supported the assumption that it is exactly these substances that attract hoverflies and encourage oviposition. Further analyses revealed that the orchid Epipactis veratrifolia does not mimic the alarm pheromones of just one aphid species, because the volatiles emitted by the aphids and the flower differ in amount and constitution.

An evolutionary dead end?

Is Epipactis veratrifolia a ruthless imposter? Johannes Stökl answers: “At least the plant provides a small amount of nectar for the deceived hoverflies. This is comparable to two related species, the wasp-pollinated orchids E. helleborine and E. purpurata, which lure stingy insects by mimicking their prey, mostly butterfly larvae. However, unlike Epipactis veratrifolia these species reward their pollinators by providing large amounts of nectar.”

Nevertheless, the scientist would classify the Eastern marsh helleborine as a treacherous imposter, because hoverfly larvae hatching from the eggs laid in its flowers won’t find any food there and must die. From an evolutionary perspective this seems to be a contradiction: If hoverfly larvae die, the population of this species is decimated and as a consequence the number of pollinators decreases.

“We cannot provide a coherent explanation of this conflict. However, we can imagine where the mimicry of the alarm pheromone is originated,” says Bill Hansson. The plant is remarkably aphid-free, probably due to the emission of α- and β-pinine. These two volatiles are produced by aphids in case of danger. Therefore aphids avoid everything that smells of α- and β-pinine. Both substances may have originally been used by the Eastern marsh helleborine as a defense against aphids. Once hoverflies were fooled and mistook the volatiles for aphids, they also served the purpose of attracting pollinators. [JWK, AO]

Original Publication

Johannes Stökl, Jennifer Brodmann, Amots Dafni, Manfred Ayasse, Bill S. Hansson: Smells like aphids: orchid flowers mimic aphid alarm pheromones to attract hoverflies for pollination. Proceedings of the Royal Society B, Online, October 13, 2010, DOI: 10.1098/rspb.2010.1770

Further Information:

Prof. Dr. Bill S. Hansson, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany, phone +49 (0)3641/57-1400, -1401; mobile: +49 (0)175 4308222; hansson@ice.mpg.de

Dr. Johannes Stökl, Regensburg University, Universitätsstraße 31, 93053 Regensburg, Germany, phone. +49 (0)941 943 2155, mobile +49 (0)179 9430400, johannes.stoekl@biologie.uni-regensburg.de

Picture Requests:

Angela Overmeyer, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany. Tel.: +49 (0)3641- 57 2110; overmeyer@ice.mpg.de

Dr. Jan-Wolfhard Kellmann | Max-Planck-Institut
Further information:
http://www.ice.mpg.de

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | 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

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>