There are dozens of ant species that live in Idaho!

Trying to list them all would be impossible. 🙂

Below are the most common and abundant types of ants, which are part of the insect family Formicidae.

5 ANT SPECIES in Idaho:

#1. Immigrant Pavement Ant

Tetramorium immigrans

Workers are dark brown to blackish.
They have longitudinal, parallel ridges on their head and thorax.

Immigrant Pavement Ants thrive in urban areas of Idaho. These European natives like building underground nests in areas with little vegetation. Consequently, you’ll often see them nesting near sidewalks, patios, foundations, and pavement.

Each of about 1000 ants defends a territory of around 460 square feet (43 m2). It’s common to see colonies battling for territory boundaries, especially in spring, as new colonies are established. The workers also forage for honeydew excreted by aphids, seeds, insects, fruit, and human food like bread and cheese.

Gardeners may be happy to see immigrant pavement ants around their property since they are significant predators of coddling moth larvae, a major agricultural pest in North America.

#2. Odorous House Ant

Tapinoma sessile

Types of ants in Idaho — Photo by judygva

Adult workers are usually a uniform color ranging from brown to black.
They have a distinct rotten odor when crushed.

Odorous house ants are incredibly widespread because they can adapt to nearly any habitat in North America. They tolerate various habitats from sea level to 13,000 feet (4000 m) of elevation and occupy urban areas, forests, grasslands, bogs, and sandy coastal areas.

These ants are also commonly seen in homes in Idaho.

And they aren’t just searching for a comfortable place to live; odorous house ants love sweets! In the wild, they tend to feed on aphid honeydew and flower nectar, but they will gladly take advantage of human food when available.

They often nest outside on stumps, rocks, matted grass, and other debris but use cracks and termite-damaged wood found in homes. Interestingly, these nests aren’t stationary.

Odorous house ants tend to move their nests about every 21 days. They also tend to coexist peacefully with other ant species rather than strictly defend a territory.

#3. Western Harvester Ant

Pogonomyrmex occidentalis

Western Harvester Ant (Pogonomyrmex occidentalis) — Photo by xpda

Workers are dark red and slightly shiny.
They display significant texture on their heads and thoraxes.
They have boxy heads with 12 segmented antennae.

Western harvester ant colonies in Idaho may last up to 40 years!

They inhabit arid regions like high-elevation grasslands, sagebrush, and forests and always select nest sites in open areas.

One feature that sets western harvester ants apart is their conspicuous nests. These ants construct large gravel mounds and remove the vegetation around them. You can spot the nests from aerial photographs! And these hills aren’t just for looks: choosing sites in open areas and removing the vegetation around the nest keeps them from burning during wildfires.

Don’t get too close, though. Mature colonies contain about 20,000 workers and will aggressively defend the nest, delivering painful stings.

#4. Western Black Carpenter Ant

Camponotus modoc

Workers are dull black with dark red legs.
Workers may be up to 0.5 inches long (13 mm).
They have golden hairs that are most abundant on their abdomens.

Western black carpenter ants are usually found in forested areas in Idaho.

They seem especially fond of coniferous forests but will also use aspen and hardwood forests.

They’re called carpenter ants because they usually make their nests in dead wood, such as stumps and rotting logs, especially those with some bark attached.

Unfortunately for humans, this predisposition to wood means they may damage homes in forested areas, especially log or wood homes. They can be especially troublesome because they form massive colonies, sometimes containing 50,000 workers. That many ants can certainly cause damage to a cabin or house!

#5. Western Thatching Ant

Formica obscuripes

Western Thatching Ant (Formica obscuripes) — Left photo by pileated

Most workers typically have reddish-orange heads, reddish-orange or black chests, and black abdomens.
Small workers may be all black or dark brown.
They have one node between their upper body and abdomen.

These are the only ants in Idaho that build thatched roofs for themselves!

Western thatching ants create huge dirt mounds, but rather than leaving them bare like many species, they cover them with a layer of twigs, grasses, and other small pieces of plant material. Precisely what they use depends on their location.

These thatched roofs allow them to survive a wide variety of temperature, humidity, and weather conditions. The size of the colony’s mound generally depends on its age. Those of mature colonies regularly reach 18 inches (45 cm) tall, but even taller mounds aren’t uncommon!

Take a closer look at this astonishing species in the video below.

Did you like learning about the ants that live in Idaho?

Check out these ID guides focusing specifically on different insects and arachnids in Idaho.

Do you need additional help identifying ants in Idaho?

If so, check out this excellent ID guide!

National Audubon Society Field Guide to Insects of North America

5 Types of ANTS found in Idaho!