Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists find insects can alter plant chemistry to help them find mates

19.11.2002


Each spring, amid the decaying rubble of dead prairie plants, emerging male gall wasps find mates by calling upon the chemistry prowess of their predecessors, entomologists scouring Central Illinois have discovered.


Gall wasp larvae feeding inside a stem of Silphium terebinthinacem (prairie dock)
Photos provided by John Tooker.


A female gall wasp Antistrophus rufus
Photos provided by John Tooker.



In the Proceedings of the National Academy of Sciences, they report that as adult gall wasps (Antistrophus rufus) feed in warm weather, they change the ratio of plant chemicals so that males emerging after the winter season can recognize when they are on the right stems at the right time. The study is being published in advance online the week of Nov. 18-22.

The finding is the first to suggest that insects can alter the chemical composition of plants for the purpose of mate location, said Lawrence M. Hanks, a professor at the University of Illinois at Urbana-Champaign.


The study also provides new insight on plant-insect ecology in widely diverse prairie habitats, which in Illinois have dwindled because of agriculture and urban growth to less than 1 percent of the acreage they once covered.

"Prairies hold unique plants and insects that are not thoroughly understood," Hanks said. "This study is important because it shows that insects can influence plants for their own needs, using a substitute for sex pheromones."

Specifically, the researchers found that male gall wasps respond to uneven chemical ratios in the plants. "As the insects feed, they change the plant chemistry, providing cues that help male wasps find females," Hanks said. "This is interesting, because the females are inside the stems, so they are not producing pheromones. It’s a plant’s volatile chemicals that attract males."

In essence, males smell their way to a mate. "They get chemical cues off the surface of the plant," said co-author John F. Tooker, a doctoral student in entomology at Illinois. "It’s called a short-range volatile cue."

"We don’t know how far away they can be and still smell it," Tooker said, "but once they are on the right plant the males antennate the surface and begin looking for mates." This rattling of antennae as they walk along the stem indicates they are on the right plant, "and this behavior helps them to find spots where female wasps will emerge."

"The males find these sites and defend them," he said. The males will head-butt one another, forcing some to leave. Others are driven off by wind or predators, such as spiders and beetles, requiring the wasps to find new stems amid the assorted plant debris.

Males, they found, only choose plant species that are the same as those from which they had emerged. The researchers monitored activity around two commonly found prairie plants: prairie dock (Silphium terebinthinaceum) and compass plant (Silphium laciniatum).

Winged flea-sized adult gall wasps live barely five days in the field, but they emerge continually over a 30-day period. They spend nine to 10 months as larvae living inconspicuously inside of the plants. Adult females emerge from dead stems of the plants, mate and lay eggs in live plant stems, forming galls that protect the larvae and provide nourishment. In the spring, males emerge first from the rotting stems.

Collaborator Wilfried A. Koenig, an organic chemist at the University of Hamburg in Germany, analyzed stem samples collected by Tooker and Hanks. The samples with galls had different enantiomeric ratios of monoterpenes than did the plants without galls.

It is the mix of two chemicals -- alpha and beta pinenes -- that males recognize. "Non-galled plants have a ratio of about 50-50, while galled plants have skewed ratios. If males find a stem with a 50-50 ratio," Tooker said, "they will move on. If they find a stem with a 70-30 or a 100-0 ratio, they likely will stay and find females emerging from it."

Tooker, who is seeking to understand how population control works for the wasps in natural prairie habitats, said the discovery was unexpected. "The botanists know all about the plants we are studying, but we donÕt know much about the insects in prairies," he said. "Gall wasps are very small and easy to overlook. Unless you are in the fields at the right period of the right season you are never going to see them."

Jim Barlow | EurekAlert!
Further information:
http://www.uiuc.edu/

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>