Little Black Ants Everywhere!

Odorous house ant profile

Odorous house ant has a flat, hidden node, so it cannot be seen by side profile compared to other ants.  Photo by Jody Green, Nebraska Extension in Lancaster County.

If you’re like most homeowners, this is the time of year small ants seem to be invading your home. Here in Lancaster County, household ant identification and inquiries are high. Spring has sprung, but the varying soil and air temperatures may not be stable enough to produce the food (carbohydrates, fats, proteins) to support the many ants becoming active in the ecosystem. They may be too close for comfort and here are the reasons they’re entering your space:

  1. They can.
  2. They’re hungry.
  3. They’re thirsty.

This is where your house comes in, your nice warm house with a gap under the door, hole around the window,  crack in the slab, utility openings, or voids under wood of vinyl siding. all which are entryways for hungry, foraging ants. According to Merriam-Webster, the term “foraging” is among one of my favorites and means “to wander in search of forage or food”. This foraging behavior is performed by a portion of the colony, which can include hundreds or thousands of individual ants, working together for growth and survival. When a foraging ant detects food, she uses pheromones or chemical compounds, secreted from her body to communicate with nest mates signaling, “Food is this way! Follow me!” This is why sometimes you can see a distinct trail of ants leading to food and then leading back to their nest.

Odorous house ant trailing

Odorous house ants trailing from their nest under the wood siding. Photo by Jody Green, Nebraska Extension in Lancaster County.

Here is a little information about the “little black ants*” which have been annoying homeowners over the past few months. If the descriptions below do not match your ant, collect a few intact specimens, throw it in the freezer to kill it, and take it to your local extension office. If you’re interested in sending a photo, here are some tips on how to take the best photo for identification purposes. In the case of ants, make sure you include a side profile, particular in the “waist region” between the thorax and abdomen because entomologist use the number and shape of the nodes for identification purposes.

Odorous house ants & Pavements

Ants feeding on liquid sugar bait. Odorous house ants (left) and pavement ants (right). Photo by Jody Green, Nebraska Extension in Lancaster County.

Comparison chart

Pavement ants feeding on potato chip

Pavement ants will feed on sugar, grease and protein food sources. Photo by Jody Green, Nebraska Extension in Lancaster County.

ant-pavement-ant-blue-house-wars1.jpg

Pavement ants colonies are territorial and will engage in colony wars. Photo by Jody Green, Nebraska Extension in Lancaster County.

Pavement ant nests

Pavement ants are associated with cement and concrete. Photo by Jody Green, Nebraska Extension in Lancaster County.

Solution: To stop the ants from coming into your house you have to eliminate food, moisture, and entryways into the structure. First, you’ll have to refrain from smashing and squishing the foragers you see in your kitchen (try real hard!) because their existence can help you answer these two questions:

  1. Where are they coming from?
  2. What are they eating?

If you see ants just scattered around without a distinct trail, they have not found a food source. If you see ants with something in their mandibles/mouth, follow that ant! They are headed back to the nest where the eggs, larvae, pupae, other workers, and multiple queens are located. When they return they feed the others and lay down trail pheromone to recruit and guide other workers to the most excellent food source, which may be a sticky lollipop, cookie crumb, or cupcake sprinkle. 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 and disinfect the area to remove traces of trail pheromone. If you find they are leading to a void within the structure, consider the condition of that location:

  1. Is or has there been excessive moisture at this location (i.e. faulty windows or storm damage)?
  2. Do you see the same ants every year?
  3. Have you ever seen any winged ants in your home?

If the answer to these questions is yes, then the nest may be in your house, and you need with a labeled insecticide in order to safely and effectively eliminate the colony.

Pavement ant with crumb

Pavement ant with a big crumb in its mandibles. This is the ant to follow! Photo by Jody Green, Nebraska Extension in Lancaster County.

Treatment: The most inexpensive option right now for odorous house ants and pavements in Nebraska is to use a sugar bait like Terro Liquid Ant Bait. The stations and the drops normally sell for less than $5 at most grocery or hardware stores.

  1. Clean up the areas to remove all competing food sources, especially sugary ones.
  2. Keep baits away from pets or children. It can be sticky and messy, and you don’t want that stuff all over.
  3. Apply bait as close to the trail as possible, as close to the nest or exterior wall as possible. They are not welcome in your kitchen.
  4. Do not smash or squish the foragers you see (try even harder!) because their existence will be short-lived, but help eliminate the portion of the colony you can’t poison directly.
  5. Monitor the bait, assure there is enough bait and allow ants to continue to feed until you no longer see any ants.
Odorous house ants

Odorous house ants feeding on sugar bait on the outside of the foundation wall. Photo by Jody Green, Nebraska Extension in Lancaster County.

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

Confessions of an Extension Entomologist: My house has five different species of ants living outside in the soil along the foundation. I was having a great time observing ant behavior, only plucking a couple samples to compare them to specimens homeowners were bringing into the lab for identification. Until…an odorous house ant made its way into our bathroom! My husband commented on my poor pest management skills and questioned my intentions as an entomologist – Then I felt forced to bait the colony. They ate up the sugar bait, took it to their nest, and not a forager could be seen after 24 hours. I’m actually a little sad now.

Keep calm and respect the critters,

Jody

Pavement ant foragers

Pavement ants foraging for food in early spring. Photo by Jody Green, Nebraska Extension in Lancaster County.

*Note: There is a species of ant with the common name, little black ant – Monomorium minimum, but neither of the ones listed in this post is this particular species.

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