There are 330 species of ants in Arizona, 318 native and 12 introduced! (AntWeb) They come into our homes searching for food. If they find it, the ant that scouted out your house will go back and inform the others. Soon you will have a trail of hundreds of ants entering your house to pick up food and returning to the nest. They live in colonies that range in size from a few individuals to millions.
Size: 1/16 to 1/2 inch in length
Habitat: They live outside in underground nests.
Prey: Depending on the species, ants can be vegetarians or predators. Some harvest leaves and seeds, while others eat flower nectar, aphids, insects or scavenge for other types of food. When there is a shortage of food outside, they will enter homes searching for it where they often find it in kitchens and pet bowls. Arizona leafcutter ants (Acromyrmex versicolor) harvest leaves that they use to grow a garden of fungus inside their nest. They then feed on the fungus.
Danger: If you disturb ants, they will most likely sting you, but, like bee stings, unless you are allergic to it they are generally not life threatening. The severity of the sting depends on the species of the ant. The introduced red fire ant (pictured above) has a particuarly painful sting that results in a pustule on the skin. These ants occur throughout the Southeast and in New Mexico and have been introduced to California, but are not present in Arizona. Active monitoring and control measures are ongoing to attempt to keep these ants outside of the state (Red Imported Fire Ant).
Some Links to Information about Ants:
Fire Ants – Scott Bauer (Public Domain), Ant head – Steve Jurvetson (Creative Commons Attribution 2.0 License)