4954 N. Shamrock Place, Tucson, AZ 85705

Cornfield Ant

Lasius aleinus

Cornfield Ant

Life Cycle

Complete Metamorphosis

New colonies are formed when mating flights occur in late summer to fall.  Eggs are laid and will hatch the next spring.  At this time the queen cares for the young until she has a worker caste that can assist and take over the care of the eggs.  The life cycle in an established colony takes an average of 3 weeks in the egg stage, in additional 3 weeks in the larval stage, with egg to adult stage being completed in about 4 months during warmer months.


  • Diet: Insect juices and seeds.
  • Activity: Outdoors
  • Preferred Climate: Warm
  • Defense: Do not sting
  • Cautions: Clusters of mounds can take over open grounds, lawns.
  • Home Invasion: They prefer to reside in open areas in yards, fields, golf courses. It is rare they are found inside, and typically if found inside, their nest site is outdoors. Nests will often be under rocks, woodpiles, along edges of landscaping. They are evident because of their cone-shaped mounds which can often develop into clusters of mounds if left untreated.

Helpful Hints

  • Quick response to treatment to avoid clusters of mounds forming.
  • Regular pest control maintenance plan to ensure you are on top of pest problems when they begin.
  • Maintain lawn and yard.

Interesting Facts

Cornfield ants store corn root-aphid eggs in their burrows during the winter and places the aphids back on the plants during the following spring.


This ant may bite, but generally, causes little more than itching or slight stinging.

Nesting Sites

Symptoms of cornfield ant infestation usually include:

  • Special attention to soil
  • Formation of small craters, especially in lawns
  • Nesting in soil under stones, bricks, sidewalks and other concealed sites
  • Rotting logs and stumps
  • Rarely do these nest in homes