"One of the things that makes plants so ecologically interesting is that they can't run away," says John Orrock, a zoology professor at the University of Wisconsin–Madison. "You can't run, you can't necessarily hide, so what can you do? Some plants make themselves less tasty."
Some do this either by boosting their production of toxic or unpleasant-tasting chemicals (think cyanide, sulfurous compounds, or acids) or through building physical defenses such as thorns or tougher leaves.
But, he adds, "Defense is thought to come at a cost. If you're investing in chemical defenses, that's energy that you could be putting into growth or reproduction instead."
To balance those costs with survival, it may behoove a plant to be able to assess when danger is nigh and defenses are truly necessary. Previous research has shown that plants can induce defenses against herbivores in response to airborne signals from wounded neighbors.
But cues from damaged neighbors may not always be useful, especially for the first plant to be attacked, Orrock says. Instead he asked whether plants — here, black mustard, a common roadside weed — can use other types of cues to anticipate a threat.
In a presentation Aug. 6 at the 2013 Ecological Society of America Annual Meeting in Minneapolis, he and co-author Simon Gilroy, a UW–Madison botany professor, reported that the plants can eavesdrop on herbivore cues to mount a defensive response even before any plant is attacked.
Slugs and snails are generalist herbivores that love to munch on mustard plants and can't help but leave evidence of their presence — a trail of slime, or mucus. Where there's slime, there's a snail. So Orrock treated black mustard seeds or new seedlings with snail mucus, then tested how appealing the resulting plants were to hungry snails.
The result? Getting slimed made the plants become less palatable. "That shows that plants are paying attention to generalist herbivore cues and that they turn on their defenses before they even get attacked," says Orrock.
What's more, they used the information in a time-sensitive way. Plants exposed only as seeds were eaten more — evidence of lower defenses — than those exposed as seedlings.
"The more recently they receive the information about impending attack, the more likely they are to use the information to defend themselves," he says. "Not only do they eavesdrop, they eavesdrop in a sophisticated way."
With Gilroy, Orrock is now exploring the genetics — and possibly evolution — of induced defenses. "If selection is strong enough from generalist snail herbivores to drive the evolution of eavesdropping by plants, then it might be far more common than we think," he says.
-- Jill Sakai, 608-262-9772, email@example.com
Sidebar:How did they do that? Collecting snail slime
The UW–Madison zoology professor used snail slime to show that black mustard plants can use cues of predator proximity to trigger defense mechanisms against the hungry snails.
But his first challenge was collecting enough slime to treat the plants. Initially he turned the snails upside down and tapped them, but what bubbled up was just defensive mucus, not the locomotion mucus (or "slime trail") he sought.
Ultimately he devised a low-tech but effective solution: let the snails crawl around overnight on a piece of filter paper lining the bottom of a small plastic deli container, then wash the filter paper and use the resulting slime water to treat the seeds and plants.
"One thing that's so cool about ecology is that you can do really enlightening experiments very simply. Clearly, if you're interested in the molecular or chemical aspects of the question, this isn't going to cut it. But if you want to know if a plant gets paranoid with slime? This," Orrock says, shaking the container, "plus snails equals results."
John Orrock | EurekAlert!
Upcycling 'fast fashion' to reduce waste and pollution
03.04.2017 | American Chemical Society
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
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...
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...
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...
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...
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...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences