This little thief is just that—so little. It is the smallest ant and is often confused with the pharaoh ant because of its size and similar yellowish color. Thief ants build their nest next door to other ant nests and sneak in to steal food and larvae from the other colony. Thief ants also love grease so they are sometimes called “grease ants.” Thief ants may not even be noticeable because they may not forage outside their nest for food; they may go undetected unless you spot a trail of ants heading straight for some greasy substance in your kitchen (such as meat, cheese, peanut butter, etc.). They may nest indoors (behind wallboards or baseboards) or outdoors (in soil or rotting wood) and nests are hard to find. When killed, thief ants will curl up into a ball.
Although thief ants do have a small stinger, it should not hurt terribly. If the sting does bother you, it can be treated with basic over-the-counter medications, such as calamine lotion and antihistamine, which will help stop the itching and burning.
Thief ants are easily confused with pharaoh ants, but the treatments for both ant types are very different. So, it is important to have a professional identify which type of ant you have. Thief ants may indicate another ant infestation. After treating for other ants, if necessary, the thief ants will begin foraging for their own food. At this stage, one or more of the following methods may be used.
Outside insecticide: If the nest is located outside, the professional will spray or douse the nest with a strong concentration of insecticide.
Poisoned baits: If the nest is located inside, the professional will attract the thief ant foragers with a grease-based bait that the thief ants will carry home for their—unbeknownst to them—last meal. Gradually you will see less and less ants until finally the entire colony has been killed.
Thief Ants DIY Pest Control
Before you begin, be sure the ants are thief ants and not pharaoh ants, as those ants look similar but require different bait methods.
Homeland Security (indoors):
If you can’t beat ’em, feed ’em. Put out a granular grease/protein-based bait or liquid bait for the ants to carry home to their queen.
Don’t spray! Spraying or dusting the thief ants or nest will do more bad than good. The colony will just break up into several smaller colonies and relocate.
Behind Enemy Lines (outdoors):
Outside insecticide: Spray aerosol pesticide around the nest and lay out baits near the nest entrance.
Nest toxicants: Make it rain on their parade. The most effective of all treatments involves dousing the nest and surrounding area directly with toxicants. (When the nest is located indoors, drill into walls and use insecticide dust instead.)
Thief Ant Green Pest Control Solutions
If you’re interested in an environmentally-friendly way to rid yourself of thief ants, consider the following green solutions to discourage these ants from coming back.
Your mom was right; you need to clean your room! If you have a problem with thief ants, you need to do some thorough cleaning. Sweep areas free of food crumbs, wash the floors, vacuum, clean recyclable containers before using, etc. Clean up spills immediately and put food away soon after eating.
Caulk and block areas of entry.
Trim the tree. Trim back trees and shrubbery away from the house to destroy any natural bridges.
Can’t touch this! Move mulch, woodpiles, stones, and bricks away so they aren’t touching the house as those materials are often house ant colonies.
Do some home improvement. Replace leaky pipes and moist materials, and patch up any holes in screens.