Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Invasive species: Those who live together invade better


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:

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

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: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Earlier flowering of modern winter wheat cultivars

20.03.2018 | Agricultural and Forestry Science

Smithsonian researchers name new ocean zone: The rariphotic

20.03.2018 | Life Sciences

Molecular doorstop could be key to new tuberculosis drugs

20.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>