Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Invasive species: Those who live together invade better

13.09.2002


While the spread of imported fire ants has received much public attention, another invader has been quietly sucking the juices from plants in our lawns and fields: a legless mealybug. In a recent study published in the September issue of the peer-reviewed journal Ecology, scientists have discovered that these bugs may be a possible key to the success of the infamous invasive fire ants.



"Widespread association of the invasive ant Solenopsis invicta with an invasive mealybug," a study by Ken R. Helms and S. Bradleigh Vinson of Texas A&M University, started after the scientists noticed mealybugs and aphids living in underground shelters close to fire ant colonies.

"It seemed clear that there was potentially something important to it all," said Helms.


Helms and Vinson studied grasses and plants from four sites in east Texas, looking for mealybugs and aphid colonies on or near the base of plants. They took samples of mealybugs and aphids from over 2100 shelters around 86 fire ant mounds throughout the spring, summer, and fall, when the ants are most active. With the mass of bugs they collected, they went to work determining how many and what types of aphids and mealybugs were present. During their study, Vinson and Helms also noticed the ants built the shelters for the other insects out of nearby materials on the ground. The researchers found that almost 70% of the biomass collected from the underground shelters near the ant colonies was the invasive mealybug Antonia graminis.

Of Asian origin, these legless creatures were first noticed in the US in the 1940’s. How exactly they entered the United States and spread is unclear. A. graminis, currently exists in over 80 countries around the world, a successful and well traveled invader. Native aphids and other native varieties of mealybugs, some with legs, others without, were found in the shelters too, but nowhere near the amount of the legless invader.

The researchers aren’t sure why the ants build the shelters for these other insects. Some of the colonies of imported fire ants were observed tending these insects on plants, without shelters. Such a symbiotic relationship may allow the ants to feed without the dangers associated with crossing across the ground outside to reach aphid and mealybug colonies on exposed plants, as well as protect the aphids and mealybugs from predation. Avoiding higher temperatures and inclement weather could also be a benefit for all the species involved. Yet, whether the ants create the shelters so aphids and mealybugs can be attended more safely, or whether the ants are exhibiting a general habit of covering and exploiting long-lived food sources, remains unstudied.

The mealybugs do appear to add to the success of the ants however. Using previous studies of other ant-aphid relations, Helms and Vinson determined approximately how much honeydew, or energy, the aphids and mealybugs would produce for the ants. They discovered that an average of 32% of the daily energy for a fire ant colony comes from A. graminis alone. Vinson and Helms investigated this link further by surveying sites throughout the southeastern US. They discovered similar relationships between the ants’ shelter building and mealybugs.

"Associations between some invasive species might be crucial to their success. Because of human commerce, species are frequently transported outside their native ranges, but very few actually become established at their new location, and of those, very few become successful enough to be considered invasive," stated Helms in a recent interview. "Both S. invicta and A. graminis are major invasive species, and our study shows that their association could be an important factor in explaining their success in the southeast United States."

The imported fire ant’s track through the US is well recorded. Native to South America, they entered the US between 1933 and 1945 in Mobile, Alabama and then spread throughout the southeastern US and California. Unlike the legless mealybug, imported fire ants have only managed to gain a strong foothold in the US, Puerto Rico and the Virgin Islands, and are starting to spread into Australia. A. graminis may be an important food source for the ants, and part of the reason they have been so successful in the southeastern US.

According to the researchers, other successful invasive ant species have also been seen tending aphids and mealy bugs, including invasive ant species that live in similar ranges to the invasive mealybug. Few studies have really delved into any possible links, however.

Fire ants have long been a problem, disabling native ant populations and harming humans, pets, livestock, and other living organisms. The mealybugs pose a problem by feeding upon and damaging agriculturally important grasses such as those used for cattle grazing, as well as those used in lawns and on golf courses. The relation between invasive species doesn’t just end with the ants and mealybugs, though.

According to Helms, "One interesting thing about where these invasive mealybugs is that they live on grasses that are mostly non-native. In fact, Bermuda grass is a major, if not the major, grass used in pastures, lawns, and golf courses in the southeast US, and the greatest recorded density of the invasive mealybug on grasses in the US is on Bermuda grass."

Annie Drinkard | EurekAlert!
Further information:
http://www.esa.org.

More articles from Ecology, The Environment and Conservation:

nachricht Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta

nachricht Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | 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

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>