Ants typically invade structures primarily for what purpose?

Ants typically invade structures primarily in search of food. This behavior is driven by their need to feed on various food sources, which can include sugars, proteins, and fats. When food becomes scarce in their natural environment, or when they discover a reliable source within or near human dwellings, ants will often create foraging trails that lead them to these resources. This search behavior is essential for their survival and colony health, leading them to invade homes and other structures where food might be abundant and easily accessible.

While ants may also seek shelter from the weather, build new colonies, or find mates as part of their life cycle, these activities are not the primary driving force behind their intrusions into human structures. The quest for food is the most significant reason for their presence indoors, making it the most accurate answer.