Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ant invaders eat the natives, then move down the food chain

18.12.2007
The Argentine ant, Linepithema humile, is one of the most successful invasive species in the world, having colonized parts of five continents in addition to its native range in South America. A new study sheds light on the secrets of its success.

The findings, from researchers at the University of Illinois and the University of California at San Diego, appear this week in the Proceedings of the National Academy of Sciences.

The Argentine ant is tiny, aggressive and adaptable, traits that have helped it in its transit around the world. Once seen only in South America, the ant is now found in parts of Asia, Australia, Europe, North America and South Africa. It most likely made its way to these destinations on ships carrying soil or agricultural products.

Under the right conditions, the Argentine ant marches through a new territory, wiping out – by eating and out-competing – most of the native ants and many other insects. In the process it radically alters the ecology of its new home.

The Argentine ant thrives in a warm climate with abundant water, and is often found on agricultural lands or near cities. But it also invades natural areas, said U. of I. entomology professor Andrew Suarez, principal investigator on the new study. The ant is highly social, and sometimes forms immense “super-colonies” made up of millions workers spread over vast territories. In previous research, Suarez identified a super-colony in California that stretched from San Diego to San Francisco.

In the new study, Suarez and colleagues followed an invasion wave of Argentine ants across Rice Canyon, in southern California.

The researchers tracked the invasion for eight years, collecting data on conditions before and during the invasion.

“Rather than comparing an invaded to a non-invaded community, which may be different for all sorts of other reasons, we try to follow an invasion front in real time to document what this invader is doing,” Suarez said.

The researchers used a technique called stable isotope analysis to determine what the ants were eating. By calculating the ratio of heavy to light isotopes (molecular weights) of nitrogen in all members of an ecological community, scientists can determine if a particular organism is primarily a carnivore or herbivore.

What the researchers found surprised them. In the early stages of invasion the Argentine ants behaved much as they did in their own home ranges: They were carnivores, aggressively attacking and probably eating most of the other ants they encountered. But as they displaced the native species, they began foraging lower on the food chain.

Field studies showed that the ants were taking over an important food source: the honeydew excretions of aphids and scale insects that feed on plants.

“These are really important, often fixed resources, from which ants can get a huge amount of their carbohydrate fuel, the energy to fuel their worker force,” Suarez said. “As the native ants are displaced, the Argentine ants start monopolizing these resources.”

The impact on the natives was disastrous. Over a period of eight years, the number of native ant species in the study area went from 23 to two.

The findings point to a need for more long-term studies of native and non-native species, Suarez said, rather than the more common, short-term studies, which see only a fragment of the bigger puzzle.

“The way the invasive species are interacting with the environment might actually be changing over time,” Suarez said.

Only by following an invasion over time can researchers begin to understand the dynamics that allow alien species to win out over the natives, he said.

Editor’s note: To reach Andrew Suarez, call 217-244-6631; e-mail: suarez2@uiuc.edu.

Diana Yates | University of Illinois
Further information:
http://www.uiuc.edu

More articles from Studies and Analyses:

nachricht Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>