Ants

How to Identify Ants

All ants share the same basic blueprint: six legs, three body segments (head, thorax, and abdomen), elbowed antennae, and a narrow, pinched waist called a petiole.

Size and coloring vary quite a bit between species. Once you know which ant you are dealing with, you can choose a treatment that actually works.

In the San Francisco Bay Area, you are most likely to encounter one of these:

• Argentine ants (Linepithema humile): Small (1/8 inch), light to dark brown. It’s the most common household ant in Northern California. What makes it so difficult to get rid of Argentine ants is their colony structure: rather than fighting neighboring colonies, they join them, forming supercolonies that can span entire city blocks.
• Carpenter ants (Camponotus spp.): Large (1/4 to 1/2 inch), typically black or black-and-red. These ants tunnel through wood to build nests, which makes them a serious structural concern, particularly in the older wooden homes throughout the Bay Area and Sonoma County.
• Odorous house ants (Tapinoma sessile): Small (1/8 inch), dark brown to black. If you crush them, they release a sharp, rotten-coconut smell. They nest in wall voids and are drawn to anything sweet or moist.
• Pavement ants (Tetramorium immigrans): Small (3/16 inch), dark brown to black. They nest in cracks in concrete, under pavers, and along foundations. You will often spot their work as tiny mounds of fine soil pushed up through pavement cracks.

Behavior and Diet of Ants

The queen sits at the heart of every ant colony, buried deep in the nest with one job: laying eggs.

She has been doing it for years, sometimes decades, producing thousands of new workers over her lifetime.

Those workers handle everything else: foraging, nest maintenance, brood care, and colony defense.

The worker ants you see marching across your counter are almost certainly sterile females. The males exist solely to mate with new queens and die shortly afterward.

Ants are opportunistic omnivores. Depending on the species and the season, they eat sugars, proteins, fats, seeds, fruit, and dead insects.

Inside your home, they target spills, crumbs, grease, and pet food.

Argentine ants actively farm aphids on garden plants, protecting them from predators in exchange for their honeydew, which can cause significant damage to your ornamental plants and fruit trees.

While most parts of the country get a break from ants in winter Bay Area and Central Coast do not.

Winter rains flood underground nests and push ants inside for dry ground. Summer heat waves send them indoors searching for cooler temperatures and water.

This means that ants are active year-round, which is why keeping them under control in this area can be so difficult.

What Damage Do Ants Cause?

Carpenter ants can cause significant structural damage.

They hollow out wood to build nesting galleries, targeting beams, subflooring, wall voids, and window frames.

They prefer moist or damaged wood to start, but a thriving colony will move into sound timber as it grows.

The real problem is that they work entirely behind your walls, out of sight, and you might not discover the damage until it is already serious and costly to repair.

Argentine ants wreak havoc in gardens by protecting aphid colonies from natural predators, which causes aphid populations to thrive and accelerates damage to plants, shrubs, and fruit trees.

Pavement ants gradually erode the soil beneath driveways, patios, and foundations, causing cracking and settlement over time.

Ants that crawl through garbage or decaying matter can carry bacteria onto your food prep surfaces. Pharaoh ants are known to spread pathogens like Salmonella when they forage through kitchens and pantries.