What is it
“Crazy ant” is a common name that can refer to several invasive species found in the southeastern U.S. Their fast and erratic movement makes them appear crazed. This article will focus on the tawny crazy ant (TCA), as they are a large threat to Mississippi.
The tawny crazy ant’s scientific name is Nylanderia fulva. It has a long history of infestation in the southern United States, but did not become a concern for Mississippi until 2009, when it was introduced to the Gulf Coast. Though the TCA can be found in Florida and Texas, populations in Mississippi are thought to have been introduced through the shipping industry.
The TCA is a small, tawny colored ant that is easily recognized by its quick erratic movements and large numbers. The ants have multiple queens in each colony and can form super colonies where multiple colonies cooperate for food and protection. In Mississippi, tawny crazy ants may be confused with the long legged or long horned crazy ant (Paratrechina longicornus). Differences between individuals of the two species can be seen under the lens of a microscope, but P. longicornus is much less numerous than its cousin and, therefore, less of a concern at this time.
Tawny crazy ants can infest homes and yards. Millions of ants mass in any nook or cranny in which they can fit. Outdoors, ants build their nests in debris and any space that offers cover and protection, including mulch, garbage, and abandoned fire ant mounds. Inside, ants are often found inside walls and even electrical appliances.
How does it cause harm?
Crazy ants bite rather than sting, and they multiply very fast, reaching numbers in the millions in just a few weeks. Because of their large numbers, the TCA often displace local insect species as well as ground birds and other vertebrates. The millions of ants swarm in mass, displacing colonies of bees, smother hatching baby birds, and kill chickens by getting stuck in their nostrils. The ants invade homes while foraging for food and crawl all over the inhabitants. People living with ants describe phantom crawling sensations, constant tingling, and the feeling of helplessness as their space is invaded. The ant is even able to out-compete the Red Imported Fire ant, taking over colonies and killing the fire ant in the process. It is said that once crazy ants have moved in, their human neighbors miss the fire ants and want them back.
Tawny crazy ants cause at least 146.5 million dollars in electrical repairs for residents of Texas where the ant is most prevalent. It is unclear why the ants are attracted to electrical appliances and wires, but it is theorized that the heat that attracts them. Thousands of ants can clog electric devices. Cars, air conditioning units, TVs, and even lap top computers have been short circuited and ruined by the ants. When owners experience static on the TV screen or a flickering of the lights and open up the casings, they often find heaping piles of ants.
How do we stop it?
Because the crazy ants have multiple queens in a single colony and there are so many ants per colony, they can be difficult to exterminate. Over the counter pesticides can kill the insects, but they are not effective at controlling the population because they cannot kill enough of them. Baits used on other types of ants, like carpenter ants, also attract the tawny crazy ant, but are less effective for the same reason as the other insecticides. In 2008, the EPA granted permission to expand the use of Fipronil, an anti-termite pesticide, to combat the ant in seven counties around Houston. Recently, permission to use Fipronil was also granted to Mississippi. Today, the best method for control is an offensive rather than defensive approach. The most effective way to prevent the spread and invasion of homes is to keep the yard nearest the house clear of debris, mulch, and leaves.