Shouldn’t they be hibernating? The short answer is no. In California, like other mild winter states, ants continue on with reproduction, scouting, foraging and all their other activities, albeit at a slower pace. Driven by a need for food and warmth some species of ants move into human habitations, where they take up residence. It isn’t uncommon, for instance, to find entire colonies of Argentine Ants living in walls or under slab foundations, where they remain warm and dry and can
easily find their way to the kitchen. When ants take up winter residence in wall voids or under slabs, control becomes a little more challenging. Ants tend to be little more sedentary in winter, don’t go outside as much and don’t move across exterior control barriers as readily. Consequently they aren’t exposed as quickly and pest control technicians must find more creative ways to expose these pests to control measures. Effective control of ants in winter may take days or weeks to achieve and patience is required.
An especially troubling species is the Pharaoh Ant. This species is entirely commensal in all but our most southern states and remains active all year. This species prefers human habitations and can be found living comfortably indoors on every continent, except Antarctica; even in areas with very cold winters. When Pharaoh Ants take up residence it’s best to call a professional familiar with their habits. If spray treatments are applied a Pharaoh Ant colony, which has multiple queens, will split up the colony (a process called budding) and reproduce rapidly, making the problem worse. Baiting is the preferred method of control and patience is again required because control will be achieved slowly over days or weeks.