Summary: Thief ants are a big problem when they sneak indoors. Although they will definitely steal your food, their name actually comes from their favorite way to find food by stealing larvae or dead insects from other ant nests.
The thief ant is tough to eliminate due to its tiny size and its ability to nest in nearly inaccessible locations. Most pesticides will easily kill this stealthy invader on contact, but because they seldom make their presence known, you could have a full infestation before you know it.
Making a positive identification is important. Thief ants and Pharaoh ants look nearly identical, but the prescribed threatments are very different. The thief ant is usually brown or golden-yellow in coloration and it has antennae with ten segments. It is a tiny ant, measuring between 1/32 of an inch to 1/16 of
an inch. The biggest different between the two ants is their antennae. This will be a tough call unless you have a fairly high powered microscope. The Pharaoh ant has a 12-segmented antennae with a 3-segmented club, while the thief ant has a 10-segmented antennae with a 2-segmented club. Armed with that important information I'm sure you'll be a lost as the rest of us.
Thief ant queens lay eggs constantly. On any given day, a queen can lay between a few dozen to a few hundred eggs, the average being about 100. The eggs turn into larvae after 2-4 weeks, then, take about 3 weeks to pupate during warm temperatures. Larvae born in the fall will over-winter and emerge as pupae in the spring.
Did you know thief ants have a peculiar trait that few other insects have? After they die, they usually curl up into a ball. Find tiny little ants curled up in a ball and you've probably discovered thief ants. Learn something new everyday, don't you?
The thief ant derives its name from its behavior when searching for food. It will steal food from the nests of other ant species. If no food is available, it will even steal ant larvae. Besides young insects, thief ants also enjoy eating dead insects, greasy foods, seeds, dairy products, foods that are high in protein, and honeydew. They will feed on sweet foods if no other foods are available. They are sometimes referred to as “grease ants” because of their preference for foods containing high grease content.
Because they prefer to steal food rather than search for it, thief ants tend to build their nests near the nests of other ants in rotting wood, underneath bricks and stones, in tree cavities, and in crevices in the foundations of homes. Sometimes, though, they will build their homes indoors. These nests can be very hard to find. The best way to search for them is to find the trail of food thief ants leave behind that helps them find their way back to their nests. The most common places thief ants can be found are in cabinets, woodwork, trash bags, closets, and on windowsills. They will even nest in the hollows of window sills and door frames or being electrical wall outlets. Shocking!
How to Avoid Thief Ant Infestation:
• Keep your house clean on a regular basis. Thief ants and other pests are attracted to dirty places in which they can hide easily and obtain a food.
• Replace ripped screens in windows and doors immediately.
• Fix any crevices or cracks in the foundation or siding of your home.
• Clean up any spills of food or drinks quickly. Even if you are outside on your patio and accidentally spill some grease from your hamburger on the concrete, you should at least soak it up with a paper towel. Thief ants are attracted to greasy tastes, so they could scurry to the spill and then continue into your house.
• If you have shrubs or branches of trees touching your house, trim them down.
How to Handle Thief Ant Infestation:
• If you see thief ants scampering around, scoop them up with a soapy sponge.
• Caulk any holes by doors or windows to avoid letting more thief ants inside.
• Plug up the drains in your sinks and bathtubs at night.
• Make sure to put away food after consuming it, as thief ants can easily crawl into a bag of potato chips and go unnoticed because of their size.
• If the infestation is out of control, spraying an insecticide like Suspend SC directly on the ants or their nest should help.
• If thief ants are crawling inside hollow walls, drill some small holes into the walls. Then, apply a pesticide dust like Tempo 1% into the wall void.
• Use only ant baits with high protein content like Maxforce FC Ant Bait stations.
Make every effort to find the nest and eliminate it. Killing individual ants will help, but it will not fix the problem. If you cannot find their nest, call a professional exterminator to assist you, but be sure to quiz them on that segmented antennae stuff. You'll blow their minds!
Click here to watch my short video on how to control ants.