Really? Fire Ants in the Northeast?
By Chris Williams on September 22, 2015.
We tend to think of fire ants as a southern pest. Believe it or not, we have our very own fire ant species that was first discovered in Massachusetts in 1908 and is still found mainly in the northeastern U.S.
A Sting You Won’t Soon Forget!
The European fire ant (Myrmica rubra), also called the red ant, is important because of its stinging habits. These ants sting in a different way. They grab onto their victim with their jaws and then insert their stinger. The result is a burning pain followed by a large inflamed area. Sensitive individuals can have severe allergic reactions to the venom. The ants’ presence in an area interferes with people enjoying their yards or other outside recreation, especially along coastal and lakeside locations.
The European fire ant is 3/16 inch long and reddish-brown in color. If you look at it under magnification, you will see that it also has two backward-pointing spines on its back. Besides its sting, the non-native ant presents ecological problems: it collects and disperses the seeds of invasive plants, it outcompetes and displaces native ant species, it increases the populations of aphids and other plant-infesting insects, and it even attacks small animals.
No Mounds; No Obvious Nests
European fire ants do not normally have much interaction with homeowners since they usually nest in grassy, marshland areas. They require high humidity so nests are located under wood debris or leaf litter, in rotten logs, or under rocks, logs, or other large objects. There aren’t any obvious ant mounds like we associate with southern fire ant nests. European fire ants also sometimes nest in potted plants.
Although these fire ants have been in our region for over 100 years, they have only recently received attention in Massachusetts and New Hampshire. In Maine, the ants have become established in humid places along the coast. Recently though, the ants seem to be expanding their range. In Maine, coloni es have been reported at inland locations. Where the ants occur, they establish more colonies per acre than in their native Europe.
Man is Aiding In Their Spread
In Europe, European fire ants start new colonies with reproductive flights. However, in the U.S., the ants seem to be spread primarily by man, through transportation of infested plants, mulch, or soil. Existing colonies also reproduce by “budding,” when a queen, some workers, and brood simply pick up and move to a new site.
A few years ago, several yards in a Cambridge, Massachusetts neighborhood were invaded by fire ants. The ants were found in areas where children were playing, in the gardens, and under decks, and were reported to be spreading aggressively. It’s believed that this localized infestation was started when a neighbor brought infested hostas home from Maine.
Because the European fire ant has only recently become a serious problem, effective control methods for this pest are still largely unknown and undeveloped. Researchers are working on getting fire ant baits (used mostly in the south for the imported fire ant) registered for use in the Northeast. For now, prevention is the best control measure: inspection of imported plants, mulch, and soil, and cleanup of yard debris and heavy vegetation that holds moisture and provides nest sites for fire ants.