COLLEGE STATION–Many people have heard of the “roach motels” of commercials. Now, their fire ants may be able to check into the same type of accomodations. Bait stations to control fire ants on lands managed for wildlife are being developed as the result of research conducted at Texas A&M University.
Dr. S. B. Vinson, an entomology professor, led research to evaluate the effect fire ants had on small mammals. According to Vinson, studying small mammals allowed researchers to identify principles of fire ant and wildlife interaction.
“What we find can then be applied to ‘important wildlife’ like deer or quail,” Vinson said.
Learning some of the principles of fire ant behavior has allowed Vinson to begin developing new ways to control them.
According to Vinson, methods that are bait specific for fire ants do not work well because they kill the native or “good” ants too. Native ants are important to the ecosystem, he said. They kill fire ants and also move seeds from one area to another. This changes plant distribution over time, he said, and therefore, native ants need to be protected.
Vinson is developing a new system of bait stations that will utilize physical barriers to prevent any ants besides fire ants from entering the station.
One prototype uses two levels to keep good ants from reaching the bait. The bottom level has rungs like a ladder which prevent ants smaller than fire ants from reaching the next level. Fire ants are the smallest ants that make it to the second level.
The second level houses the dome containing the bait. Entry holes into the dome are small so that ants larger than fire ants cannot enter, Vinson said.
These bait stations will provide a way for land owners to decrease the fire ant populations from specific areas of their land, providing a refuge area for wildlife, Vinson said. Bait stations are being designed to last about two years, he said.
Bait stations may eventually be used to control fire ant populations in outside urban areas as well, he said.
Fire ants can be a serious problem to wildlife, he said. He has seen small animals quivering in shock which he felt was possibly due to fire ant stings.
Vinson said that fire ants in multiple queen colonies can build as many as 800 to 1,000 mounds on a single acre of land. These fire ants then compete with small mammals for food and nesting space, he said.
To do the study, researchers found land that had high fire ant concentrations and removed mounds from half the chosen area.
Then live traps were placed to catch small mammals to see if more had moved to the side with lower ant populations. The trapped animals were weighed, marked and released.
Cotton rats and pygmy mice were the most common species caught, he said.
Cotton rats tended to be in areas of lower fire ant activity, he said. A separate experiment showed that whenever fire ants entered the nest, the mother rat ate them. This left little possibility for the ants to recruit or signal other ants to come, Vinson said.
However, if the cotton rat was overwhelmed by a large amount of ants at one time, the mother would move the nest to an area with fewer fire ants, he said.
Unlike the cotton rat, the pygmy mouse tended to nest during winter when fire ant activity is lower.
This principle has become beneficial to some cattle producers. Vinson advised cattle producers to breed their cattle so that cows will calve in early spring when it is cooler instead of late spring, decreasing susceptibility to fire ant injury.
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