Field Ants

The Field Ant

Filed Ants (Formica)

Filed Ants (Formica) By Derek Parkinson, CC BY-SA 2.0,

Field ants (Formica spp) are one of the most common outdoor ants sighted in the US. They are the largest genus of ants found in New Mexico but have spread across the area. Their name itself indicates their preferred choice of habitat. They do not infest buildings but can infest areas around the building, creating a nuisance.


  • Brown body, black abdomen
  • Other species can be brown, yellow, red and black or a mix of these color
  • Body length varies from 4mm to 8mm
  • Six Legs
  • Unevenly rounded body
  • Shiny body

Appearance, Behavior, and Signs

  • Field ants make mounds out of grass, soil, twigs, and leaves. These mounds can be up to 2 feet tall and 4 feet wide.
  • Their nests are often made in open spaces, such as a grassy areas, and fields
  • Their nests can affect the quality of grass or plants in the area below and around it
  • They rarely infest the inside parts of buildings
  • They also make nests on walls, foundations, cracks in the sidewalk and the base of trees
  • Field ants can spray formic acid into the wound after biting, so their bite can be painful at times
  • They feed on honeydew from aphids and also look for sweet foods. Some species of field ants eat insects and are also partial to meat (they act as scavengers)
  • During late summer, swarmer ants fly out of the field ant mounts to establish more colonies
  • Some species of field ants collect aphids to have an abundant source of honeydew
  • Signs of field ant infestation include the sighting of field ants around the house, bodies of dead aphids and insects and sighting of field ant mounds


Many residents get field ants in their backyards and gardens. Field ants prefer open spaces – they will rarely infest homes. However, they can wander inside in search of food. Your basement, foundation, and walls are the vulnerable areas where field ants can nest. If any trees are in contact with the walls of your house, field ants might crawl their way inside. They can also enter through cracks in the walls and loose floorboards and tiles. They might even enter the house through the firewood (they often hide in there).


How to get rid of field ants

How to get rid of field ants.By Yash raina – Own work, CC BY-SA 4.0, 

Invasion of field ants can be prevented by sealing all cracks and trimming all the plants around the house. Make sure your foundation and basement are sturdy. Regularly check your garden or yard for field ant mounts. Ensure that firewood is stored far away from the house. Prevent accumulation of mulch near the foundation. Remove any hollow tree trunks or tree stubs that might be present in your garden or backyard. Replace weather stripping whenever it gets damaged.

It is better to contact a professional pest control service if you want to eliminate a field ant mound. These mounds can be deep inside the ground as well and will have millions of ants. A field ant infestation can only be wiped out if the queen is killed, and the queen ant rests deep inside the mound. Homeowners can try using store bought liquid pesticides and solid bait granules to eliminate the ants.

Field Ant Facts

  • They resemble carpenter ants and fire ants and are often mistaken for the same
  • They are not very aggressive in nature; however, they can bite if threatened
  • They are also known as thatch ants and wood ants
  • The thorax of a field ant is bumpy in appearance

Continue Reading About Ants

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