ANTS: Argentine (Iridomyrmex humilis)
The most common structure-infesting ant, in Southern California, is the Argentine ant. They are small, a little more than an eighth of an inch long, with light brown to shiny black bodies and are often seen actively traveling in trails in large numbers.
The Argentine ant is the most persistent and troublesome ant in our environment. Argentine ants are very aggressive and will drive out other ant species from their territory. They nest and proliferate in damp soil of landscapes, under rocks, ground covers, walks and even in a crack of a concrete slab. They also commonly nest in sheaths of palm trees and under plastic sheeting covered with decorative landscape bark. When aphids are present on the landscape plants, they harvest the honeydew secretions and tend the aphids as caretakers and protectors. Argentine ants develop huge colonies with endless trails going to and fro in and around structures, invading everything in an occupied building in search of food. Entomologists at the UC Riverside, have told Pestgon, Inc., that the huge colonies are actually just one monstrous, super colony covering all of Southern California.
Their prodigious numbers can be overwhelm a lunchroom, kitchen or office environment. Ants gain access through the most minute cracks and openings and will travel up trees and shrubbery, even telephone wires to enter a building.
Although ants don't generally harm a structure, their presence will trigger the tenants call to arms if they are found anywhere in an office environment. A regular monthly pest service is the best way to eliminate the possibility of a massive influx of ants during the summer months.