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 Loss of habitat causes double damage to species richness
02.04.2019 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Deep decarbonization of industry is possible with innovations
25.03.2019 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

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: Energy-saving new LED phosphor

The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.

Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.

Im Focus: Quantum gas turns supersolid

Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.

Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...

Im Focus: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

Proteins stand up to nerve cell regression

24.04.2019 | Life Sciences

New sensor detects rare metals used in smartphones

24.04.2019 | Life Sciences

Controlling instabilities gives closer look at chemistry from hypersonic vehicles

24.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>