Uninvited: Pavement Ants and Odorous House Ants

Odorous House Ants - Vicki Jedlicka

Don’t Let Ants Come Over Uninvited

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Don’t Let Ants Come Over Uninvited

by Jody Green, Extension Educator

Here in Lancaster County, household ant identification and inquiries are high. Spring has sprung, but varying soil and air temperatures may not be stable enough to produce the food to support the many ants becoming active in the ecosystem. Believe it or not, ant nests are primarily located outdoors and they serve an important role in the food web as a natural predator to insects and arthropods. The reasons they enter your space include hunger, thirst and easy entry.

Your nice warm home may have a gap under the door, hole around the window, crack in the slab, utility openings or voids under wood of vinyl siding — all of which provide an open entryway for hungry foraging ants. The term foraging means “to wander in search of forage or food.” When a foraging ant detects food, she uses pheromones — chemical compounds — secreted from her body to communicate with nest mates that signal, “Food is this way! Follow me!” This is why sometimes you can see a distinct trail of ants leading to food and back to their nest.

It is important to know that though you feel as though your home has been invaded by multitude of ants, foragers comprise only a small portion of the colony. The rest of the colony, which include queens, eggs and larvae remain in the nest, most often located outdoors. Ants are social insects and they have a distinct caste system where each caste performs a specific task or job, and the foragers job is to find food to feed the colony.

Two common ants that are commonly referred to as “little black ants” are the pavement ant and the odorous house ant. Both ants are approximately 1/8-inch long, a brown-black color and associated with human activity. Neither species has an aggressive sting or bite. Rather, they are a nuisance when they enter homes and try to share/steal food. Both ants are considered “sugar ants,” but have dietary needs like humans and at times feed on live and dead insects for protein.

Pavement Ant

As described by their common name, pavement ant colonies are most often found in soil near or under sidewalks, driveways, slabs or rocks. They work tirelessly to excavate galleries underground, moving individual particles with their mouthparts. Their nests have piles of loose sand or dry particles along cracks, vegetation, stones, expansion joints, window sills, baseboards or tiles. Pavements will forage on kitchen floors and counters.

Odorous House Ant

As described by the common name, odorous house ants are associated with houses and known to emit a very strong odor when crushed. The smell has been described as rotten coconut, licorice-like and/or a lemon-scented cleaning solution. Colonies can be found in close proximity to human activity and residences as nests can be found in landscape mulch, under boards, lumber, firewood, bricks, stones, debris and cardboard. When they located a food source they are known to have very district trailing behavior.

Integrated Pest Management for Ants

The first step in any pest issue is identification. Did you know there are close to 1,000 ant species in North America? Only a handful of them are household pests, but each one of those has a distinct appearance, behavior, feeding preferences and habitat. In order to eliminate the ant, you have to get to know the ant. The second step is to remove the conducive conditions that have allowed the ants to succeed thus far. Things like eliminating food, moisture and sealing up entryways into the structure. If you find they are trailing outdoors, seal the gap or hole with caulking or sealant appropriate for the location. Clean up the food source, which may be a piece of candy, cookie crumb, cupcake sprinkle or potato chip, then disinfect the area to remove traces of trail pheromone.

The third step is treatment which may include using an ant bait specifically for sugar-feeding ants. The concept of ant bait is to have an attractive, palatable, slow-acting toxic food source the ants will find and take back to the nest, share among nest mates and poison the entire colony. Both the pavement ant and the odorous house ant will readily feed on a liquid sugar ant bait, which can be purchased reasonably and easily at grocery and hardware stores.

  • Read the label and follow instructions.
  • Clean up to remove all competing food sources, especially sugary ones.
  • Sugar bait can be sticky and messy. If they are not in ready to-use stations, place droplets on small squares of aluminum foil.
  • Apply bait as close to the trail as possible, as close to the nest or exterior wall as possible. Refrain from putting bait on the kitchen counter.
  • Do not smash or squish the foragers you see because you need them to take the bait back to the colony.
  • Monitor activity, make sure there is enough bait and allow ants to feed until there are no more foragers.

Possible reasons for control failure could be not enough bait for the size of the colony, changes in food preference and/or misidentification. Many ant baits are not labeled for carpenter ants because besides sweet food sources, a large portion of their diet consists of other insects, so a sugar bait alone will have little effect on the health of a colony.

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Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the University of Nebraska–Lincoln is implied. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office

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