Types of Ants Commonly Found in California’s Central Valley

Understanding the specific ant species invading your property is crucial for effective ant control. Here are some of the most common ants found in the Central Valley of California:

• Argentine Ants: These are one of the most aggressive and common ant invaders in the Central Valley. Small (around 1/8 inch), light to dark brown, they are known for moving in large, coordinated trails. Argentine ant colonies are enormous, often with multiple queens, and can form supercolonies, making them incredibly difficult to eliminate with DIY methods. They nest in walls, foundations, and damp areas, and are drawn indoors by water, especially during droughts or extreme heat, and food. While they don’t bite or sting, they spread quickly and outcompete other ant species.
• Odorous House Ants: About the same size as Argentine ants, these dark brown to black ants are known for the foul, rotting coconut scent they release when crushed. They move in erratic patterns and nest in wall voids, behind appliances, and near water sources. Odorous house ants are experts at quickly relocating if threatened, making them persistent pests.
• Pavement Ants: Small and dark brown or black, pavement ants are slow movers commonly seen crawling out of sidewalk cracks, driveways, and patio stones. They love to build nests under concrete and are often drawn indoors by sweet or greasy food. Their nests can cause structural damage over time due to erosion beneath sidewalks and foundations.
• Carpenter Ants: These larger ants, ranging from 1/4 to 1/2 inch long and typically black or reddish-black, tunnel through damp or decaying wood to build their nests. They are often mistaken for termites because of their wood-nesting habits, but unlike termites, they don’t eat wood; they excavate it to create galleries. Signs of a carpenter ant infestation include sawdust-like debris (frass), rustling sounds in walls, or wood that sounds hollow when tapped. If left untreated, they can cause significant structural damage to homes over time.
• Fire Ants (Southern Fire Ants and Red Imported Fire Ants): These reddish-brown ants are known for building large soil mounds in sunny yards and for their painful stings. Southern fire ants are adaptable and opportunistic, with colonies found in lawns or gardens. Red imported fire ants are particularly aggressive, and their stings can cause itching, swelling, and in some cases, allergic reactions. They are highly territorial, and disturbing their nest can result in multiple stings. Red imported fire ants have established themselves in California, often spreading through the movement of infested soil.
• Pharaoh Ants: These tiny, yellowish or honey-colored ants (1/16 inch) prefer indoor environments and are known for quickly forming new colonies. They often nest in wall or cabinet voids, behind baseboards or insulation, or outdoors in debris. Pharaoh ants are particularly troublesome in environments like hospitals because they can spread pathogens.
• Thief Ants: Aptly named, these tiny, yellowish ants (1/32 inch) are known for infiltrating other ants’ nests to steal food, and they have an affinity for greasy and protein-rich foods. They nest outdoors in soil or under rocks or decaying wood, and indoors behind wallboards or baseboards.