Navigation Links
Orchid tricks hoverflies
Date:10/14/2010

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 Stkl. 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 Stkl 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]


'/>"/>

Contact: Bill S. Hansson
hansson@ice.mpg.de
49-175-430-8222
Max Planck Institute for Chemical Ecology
Source:Eurekalert  

Related biology news :

1. Common orchid gives scientists hope in face of climate change
2. Breeding orchid species creates a new perfume
3. First known instance of a cricket as an orchid pollinator captured on film by Kew scientist
4. Orchids and fungi -- partners for life
5. Orchid Cellmark Reports Third Quarter 2008 Financial Results
6. Chemist receives NIH funding to unravel tricks of neuronal wiring
7. Researcher tricks immune system in diabetic mice
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Orchid tricks hoverflies
(Date:5/16/2017)... 2017   Bridge Patient Portal , an ... MD EMR Systems , an electronic medical record ... have established a partnership to build an interface ... GE Centricity™ products, including Centricity Practice Solution (CPS), ... These new integrations will allow healthcare delivery networks ...
(Date:4/19/2017)... York , April 19, 2017 ... as its vendor landscape is marked by the presence ... market is however held by five major players - ... Together these companies accounted for nearly 61% of the ... the leading companies in the global military biometrics market ...
(Date:4/13/2017)... 13, 2017 UBM,s Advanced Design and Manufacturing ... feature emerging and evolving technology through its 3D Printing ... run alongside the expo portion of the event and ... demonstrations focused on trending topics within 3D printing and ... manufacturing event will take place June 13-15, 2017 at the ...
Breaking Biology News(10 mins):
(Date:8/16/2017)... King of Prussia, PA (PRWEB) , ... August 16, 2017 , ... ... leaders will be taking part in sessions at the ISPE Annual Meeting and ... the Marriott Marquis San Diego Marina. The event’s theme is “Driving innovation to advance ...
(Date:8/16/2017)... ... 16, 2017 , ... Recent studies show that cancer cells ... specific cancers, such as breast, prostate, or lung, target vital pathways active in ... advanced prostate cancer. , This therapy limits the production and effectiveness of ...
(Date:8/16/2017)... ... August 16, 2017 , ... Today, 3Bar ... has secured $2M in funding from an impressive group of investors, including Rev1 ... Thrive Fund. With this investment, 3Bar is broadening availability of its groundbreaking offering ...
(Date:8/16/2017)... -- This year,s edition of the Inc. 5000 features a now-familiar name: BioPoint ... made the list for the third year in a row. Now in ... based on a set of quantitative metrics. In addition, BioPoint was also ... the Bay State . ... Inc. 5000 ...
Breaking Biology Technology: