Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Move Over Predators: Plants Can Control the Food Chain Too - from the Bottom Up

29.03.2010
Forget top-to-bottom only. New Cornell University evolutionary biology research shows how plants at the bottom of the food chain have evolved mechanisms that influence ecosystem dynamics as well. ( Science, March 26, 2010.)

“The ecology and interactions of most organisms is dictated by their evolutionary history,” said Anurag Agrawal, associate professor of ecology and evolutionary biology (EEB), the study’s senior author.

In food webs, predators help suppress populations of prey by eating them; that frees species lower in the food chain, such as plants, to flourish, a dynamic called a “trophic cascade.” Most trophic cascade studies have focused on the ability of predators to increase plant biomass by eating herbivores. Such studies typically find strong trophic cascades in aquatic environments, where big fish eat minnows, which eat the tiny algae-eating crustaceans called daphnia.

Agrawal, first author Kailen Mooney, who is a former Cornell postdoctoral researcher and now assistant professor at the University of California-Irvine, and colleagues studied trophic cascades in 16 milkweed species, famed for their interactions with monarch butterflies, and also fed upon by aphids.
Plants have evolved three main strategies for increasing their biomass as much as they can against the forces that limit their growth, said the researchers:

They grow as quickly as possible; develop direct defenses, such as toxins or prickly leaves, against herbivores; and attract such predators as ladybugs that eat their pests.

But plants do not have the resources to develop all three defenses. Since Darwin, evolutionary biologists have hypothesized that over millions of years of evolution, plant species are subject to trade-offs, developing some defense strategies in lieu of others; a key finding of the new study is that these evolutionary trade-offs drive how modern ecosystems are structured.

In the case of milkweed, some favored fast growth and the ability to attract predators while putting less energy into resisting herbivores.

The study found that one of the major factors leading to greater milkweed biomass (or growth) is the production of volatile compounds called sesquiterpenes, which attract such predators as aphid-eating ladybugs. But surprisingly, the plants’ biomass increases regardless of whether ladybugs or other aphid predators are present.

The reason, the researchers suggest, is because the trait to produce sesquiterpenes appears genetically linked to faster growth; the strategy here is to replace leaves faster than they can be eaten. At the same time, milkweed species that put more energy into growing faster put less energy into resisting such pests as aphids.

“Because no species can do everything, milkweeds that grow fast necessarily have lower resistance to aphids,” said Agrawal. “Thus species that grow fast benefit the most from predators” of aphids.

The findings have implications for agriculture, as conventional strategies for controlling pests often involve spraying insecticides, said Agrawal. “By including the evolutionary history in our understanding of natural pest management, we gain insight into plant strategies that have stood the test of time, and this may provide hints for breeding crops with traits that ensure robust lines of defense,” he added.

Co-authors include Andre Kessler, assistant professor, and postdoctoral researcher Rayko Halitschke, both in EEB at Cornell.

The study was funded by the National Science Foundation, Cornell Center for a Sustainable Future and University of California-Irvine’s School of Biological Sciences.

Blaine Friedlander | Newswise Science News
Further information:
http://www.cornell.edu

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Individualized fiber components for the world market

23.06.2017 | Physics and Astronomy

How brains surrender to sleep

23.06.2017 | Life Sciences

Can we see monkeys from space? Emerging technologies to map biodiversity

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>