Ants are the worst pest in the world, and we’re not exaggerating when we say that. Homeowners say so, listing the insects before cockroaches, spiders, and bed bugs. But even though ants don’t spread diseases or bite like other common pests, they’re still a major nuisance. With colonies that are not only massive, but also tightly knit, it’s no wonder they’ve made it all over the globe – from Croatia to China to our home state of California. Here’s how ants have become the top pest everywhere, including our insect-ridden region.
As a California resident you’ve probably noticed the many different ants that call this state home. With over 160 ant species identified in California so far, it can be hard to keep track of which ones are taking over your kitchen or swarming your picnic. To help make sense of our ant invaders I’ve put together this guide to the 10 most common ants in California.
1. Argentine Ant
The tiny Argentine ant is one of the most widespread ants in California. These ants live in enormous colonies with multiple queens, making them difficult to eliminate. Originally from South America, they likely hitchhiked to California in cargo shipments.
Argentine ants thrive in urban areas and often invade homes in search of sugary foods, You’ll find long trails of them marching outside or clustering around kitchen counters Getting rid of Argentine ants takes persistence – take away their food and water sources and use ant baits near their trails
2. Odorous House Ant
Despite their name odorous house ants don’t actually smell. They got their name because they swarm when crushed like when you step on an ant mound and get overwhelmed by the odor. These ants live underground in colonies up to 10,000 strong.
Odorous house ants forage day and night for sugary foods, especially juices from ripe or overripe fruit. They follow invisible scent trails between food and their nest. To control these sugar-loving ants, clean up fallen fruit as soon as possible and wipe away any ant trails.
3. Southern Fire Ant
With a painful sting, the southern fire ant is one red ant you want to avoid. Native to California, these ants build colonies under rocks or mounds of loose soil. Their diverse appetites range from honeydew to dead insects.
Southern fire ants aggressively defend their colonies. Multiple stings can cause swelling, itchiness, and irritation in people. Watch for these ants marching in single-file lines in open, sunny areas and wear closed-toe shoes in infested yards.
4. Western Carpenter Ant
As their name suggests, western carpenter ants burrow into wood, potentially causing major structural damage over time. These large black ants hollow out galleries in logs, trees, and wooden buildings, leaving behind a telltale sawdust-like material.
Though carpenter ants don’t eat wood, their excavated nests compromise structures. Signs of an infestation include ants crawling on walls or ceilings and small piles of the coarse sawdust they kick out of their nests. Call a pest control expert if you suspect carpenter ants inside.
5. Red Imported Fire Ant
Originally from South America, these fiery ants have slowly spread across the southern United States, including parts of California. They live in large mounds, often near open, sunny fields. When threatened, red imported fire ants swarm out to viciously sting the intruder.
Their potent, painful venom can cause severe allergic reactions in some people. Multiple stings often result in pus-filled blisters that take weeks to heal. Stay far away from any ant mounds and wear closed-toe shoes in infested areas. Seek medical help immediately if bitten by these ants.
6. Western Harvester Ant
The western harvester ant collects and stores seeds in underground chambers. These ants rely on certain seeds as their main food source. Harvester ants can become defensive when their seed-gathering is interrupted by people crossing near their trails.
Their stings are quite painful, but not medically dangerous. Give any harvester ant trails you come across a wide berth. Their nests are marked by small pebbles and debris the ants clear away at the entrance. Disturb them at your own risk!
7. Argentine Ant
See #1.
8. Odorous House Ant
See #2.
9. Southern Fire Ant
See #3.
10. Western Carpenter Ant
See #4.
As you can see, ants are a complex and ubiquitous part of life in California. The ant species covered here represent some of the most common intruders that make their way into our homes and backyards. Understanding their behavior and nesting habits allows us to take proactive steps to control infestations and avoid potentially dangerous encounters.
While ants can certainly be pests, they also play important ecological roles, such as aerating soil and dispersing seeds. Whenever possible, avoid toxic ant killers and use more natural methods like eliminating food sources and removing nesting sites. A little knowledge about our ant neighbors creates healthier communities for people and insects alike.
The Southern California Ant Takeover
Ants have taken advantage of travel to make it to virtually every corner of the Earth. The more we become a globalized society, the easier it is for ants to reach commercial and travel hubs like Southern California via cargo ships, trucks, and even airplanes. It’s hard to imagine tiny ants surviving at 30,000 feet, but it’s indeed possible. In our region, there are two foreign species – often called “tramp ants” – that have quickly taken over: Argentine ants and red imported fire ants.
Rather than the invading ants having to adjust to new environments, we’ve already done the work for them, adjusting ourselves with green lawns, food-filled buildings, and interiors with plenty of hiding places. Southern California used to be full of odorous house ants and harvester ants, but now sees Argentine ants outcompete them in crowded cities while red imported fire ants have come to dominate the desert.
In the Desert: Red Imported Fire Ants
In the Southern California desert (notably, the area stretching from Palm Springs to Coachella), fire ants reign supreme. Two species call the desert home: the native fire ant and the invasive fire ant, also called the red imported fire ant.
Both species crave dry environments – hence, they’re both fond of the desert. But it’s the red imported fire ant that’s more concerning because it’s much more aggressive.
Red imported fire ants’ colonies, like Argentine ant colonies, are bigger than most ant colonies – with populations often numbering in the millions. They live underground, coming to the surface in search of nearby food sources. Unlike Argentine ants, they spend all their time outdoors, seeking nearby insects, honeydew, and vegetables to satisfy their omnivorous appetite. Be wary of finding the ants near you – their large dirt mound nests are everywhere from backyards to parks to and baseball fields.
A good reason to be wary of fire ants is their stinging ability, which, added to their massive numbers, makes them a big health threat. Taking care of a nest sooner rather than later is key to avoiding a painful encounter.
If threatened, the ants will send out an alarm pheromone, quickly pouring out through the opening of their nest to attack you relentlessly. They don’t sting once, but over and over – there have been instances of people getting stung thousands of times. Ouch!
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FAQ
Are ants a problem in California?
Carpenter ants, Camponotus species, and velvety tree ants also invade buildings in California. Although they don’t eat wood as termites do, they hollow it out to nest and may cause considerable damage.
What is the most common ant in California?
The most common ant occurring in and around the house and garden in California is the Argentine ant, Linepithema humile (formerly Iridomyr- mex humilis).
What is ant season in California?
Spring and summer is high season for ants and for ant pest problems in our California homes and gardens.
What is the problem with Argentine ants?
Argentine ants do not pose an extreme health threat, but they are known to crawl over sewage, trash and dead animals while looking for food and can be carriers of disease-causing bacteria for conditions like dysentery. If they gain access to a household’s kitchen, they are capable of contaminating food.