Types of Spiders & Ants Commonly Found in California’s Central Valley

Understanding the specific spider and ant species prevalent in our area is crucial for effective control. Here are some of the most common invaders you might encounter:

Common Spider Species in Our Service Area

• Black Widow Spiders (Latrodectus hesperus): These notorious spiders are common throughout California, including Yolo County. Adult females are shiny black with a distinctive red hourglass marking on the underside of their abdomen. They prefer dark, dry, secluded, and undisturbed areas such as garages, crawl spaces, woodpiles, outdoor sheds, and under furniture. Their venomous bite can cause severe pain, muscle cramps, and illness, especially in children, the elderly, or those with compromised health. Bites often occur when people disturb them while cleaning or reaching into cluttered areas.
• Yellow Sac Spiders (Cheiracanthium mildei): These small, pale yellow spiders have a slightly darker stripe on their abdomen. They are often found indoors, spinning silken sac webs in ceiling corners, behind shelves, and pictures. Outdoors, they inhabit shrubbery. Bites typically happen when the spider is trapped against the skin, causing initial pain similar to a bee sting, redness, and sometimes swelling.
• Wolf Spiders (Lycosidae family): Large, hairy, brown or gray spiders, wolf spiders are fast, solitary hunters that do not spin webs to catch prey. They are often found in basements, under furniture, in laundry piles, and outdoors in leaf litter or logs. While their bites are rare and generally cause only mild pain or swelling, their appearance can be alarming.
• Cellar Spiders (Pholcus phalangioides): Also known as “Daddy Long-Legs,” these spiders have very long, thin legs and tiny gray or tan bodies. They prefer damp, dark environments like cellars and basements, and are known for their tangled, messy webs in room corners and window frames. They are generally harmless to humans.
• Common House Spiders (Parasteatoda tepidariorum): Small, brown or gray spiders with round abdomens, common house spiders spin irregular, messy webs in corners, window frames, and garages. They are typically non-aggressive and considered more of a nuisance.
• Jumping Spiders (Salticidae family): Small, often black with white or iridescent markings, jumping spiders are active daytime hunters with excellent vision. They do not spin webs for hunting but stalk and leap on their prey. They are often found on windowsills, walls, and houseplants. They are generally harmless.
• Orb Weaver Spiders (Family Araneidae): These spiders are known for building large, intricate circular webs, often seen in gardens, around porch lights, and in shrubs. They have bulbous abdomens and are often boldly patterned. Their bites are rare and cause only mild irritation.

Common Ant Species in Our Service Area

• Carpenter Ants: These ants are known for excavating wood to build their nests, which can lead to structural damage in homes and businesses. They are often larger than other ant species and can be black, red, or a combination of both. You might see their distinctive “frass” (sawdust-like material) near damaged wood.
• Pavement Ants: Small, dark brown to black ants, pavement ants are commonly found nesting under sidewalks, driveways, and building foundations. They enter homes in search of food and can be a persistent nuisance, especially in kitchens.
• Odorous House Ants: These small, dark brown or black ants emit a rotten coconut-like odor when crushed. They are highly adaptable and can nest both indoors and outdoors, often found trailing in kitchens and bathrooms, seeking sugary foods.
• Pharaoh Ants: Tiny, yellowish to light brown ants with darker abdomens, Pharaoh ants are notorious indoor pests, especially in heated buildings. They often infest warm, moist areas near drains, pipes, or wiring, and can build nests in wall voids, behind baseboards, and in insulation. Pharaoh ants can carry and transmit various diseases, making their presence particularly problematic in healthcare facilities. They are known for “budding,” where colonies split and spread rapidly if disturbed by improper control methods.