Navigation Links
Move over predators: Plants can control the food chain too -- from the bottom up
Date:3/25/2010

ITHACA, N.Y. 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.


'/>"/>

Contact: Blaine Friedlander
bpf2@cornell.edu
607-254-8093
Cornell University
Source:Eurekalert

Related biology news :

1. Layered approach may yield stronger, more successful bone implants
2. Clever plants chat over their own network
3. Plants can be used to study how and why people respond differently to drugs
4. Book on weeds and invasive plants discusses how to manage them using ecological approaches
5. A greenhouse in order to study the impact of climate change on plants
6. Agent that triggers immune response in plants is uncovered
7. Scientists ramp up ability of poplar plants to disarm toxic pollutants
8. A new baseline of invasive plants in Isabela
9. Hungry microbes share out the carbon in the roots of plants
10. Scientists warn that species extinction could reduce productivity of plants on Earth by half
11. Cell transplants may improve severe urinary incontinence
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/3/2016)... June 3, 2016 ... Nepal hat ein ... hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, Registrierung und ... der Produktion und Implementierung von Identitätsmanagementlösungen. Zahlreiche ... im Januar teilgenommen, aber Decatur wurde als ...
(Date:6/2/2016)... NEW YORK , June 2, 2016   The ... (Weather), is announcing Watson Ads, an industry-first capability in which ... advertising, by being able to ask questions via voice or ... Marketers have long ... with the consumer, that can be personal, relevant and valuable; ...
(Date:6/1/2016)... YORK , June 1, 2016 ... Technology in Election Administration and Criminal Identification to Boost ... to a recently released TechSci Research report, " Global ... By Region, Competition Forecast and Opportunities, 2011 - 2021", ... 24.8 billion by 2021, on account of growing security ...
Breaking Biology News(10 mins):
(Date:6/27/2016)...  Sequenom, Inc. (NASDAQ: SQNM ), a ... the development of innovative products and services, announced today ... States denied its petition to review decisions ... U.S. Patent No. 6,258,540 (",540 Patent") are not patent ... Supreme Court,s Mayo Collaborative Services v. Prometheus Laboratories decision.  ...
(Date:6/27/2016)... PHILADELPHIA , June 27, 2016  Liquid ... today announced the funding of a Sponsored Research ... study circulating tumor cells (CTCs) from cancer patients.  ... changes in CTC levels correlate with clinical outcomes ... therapies. These data will then be employed to ...
(Date:6/24/2016)... ... ... Researchers at the Universita Politecnica delle Marche in Ancona combed medical journal articles ... findings are the subject of a new article on the Surviving Mesothelioma website. ... blood, lung fluid or tissue of mesothelioma patients that can help point doctors to ...
(Date:6/23/2016)... 2016 A person commits a crime, and the ... track the criminal down. An outbreak of foodborne ... Administration (FDA) uses DNA evidence to track down the bacteria ... far-fetched? It,s not. The FDA has increasingly used a complex, ... foodborne illnesses. Put as simply as possible, whole genome sequencing ...
Breaking Biology Technology: