The Biggest Ant Hill

By Jim Moore, Entomologist

Jim Moore Bug Guy

Somewhere, in a remote corner of the Mountain Meadows Basin, in Lassen County, is monster ant hill at least three feet tall;  the home of Red Wood Ants.  When I first encountered this mega ant hill over twenty-five years ago it was a bit smaller and mound shaped; and it was the only ant mound to be found in the area. Now it is more like a cone shaped ant megalopolis, with three nearby smaller ‘satellite’ ant mound colonies.

Red Mound Ant Nest

Our local Red Wood ants maintain sophisticated colonies. They build their mounds in open woodland areas that provide just the right amount of sunlight. In such a location, the steep sides of the mound provide just the right amount of solar incubation for a healthy colony.  Small pieces of resin gathered from the local trees are used in the mound to prevent the growth of harmful mold and bacteria. Numerous tunnels, galleries, and entrance holes which can be closed, help to provide good ventilation and humidity within the mound. If it does get too hot, or too cold, the ants also have an extensive deep underground network of tunnels where the ants can retreat with their young. These underground tunnels may also interconnect with the satellite ant mounds.

Red Mound Ant Nest2

Mound ants are also able to kill small nearby plants that might grow and block the sunlight. They accomplish this by biting the plants numerous times and poisoning the wounds with formic acid.

The above ground mounds also warm up seasonally sooner than the competing colonies of their archenemies known as carpenter ants, giving the mound ants an important advantage over a limited early springtime food source. Mound ants are primarily hunters of small invertebrate animals; especially aphids which they find in the trees near their mounds.  They also manage herds of aphids, from which they harvest aphid honeydew.

Mound ants, like most species of ants, are primary benefactors towards a healthy local ecosystem. So, if you ever come across a giant Red Wood Ant mound within the Nor Cal woods, take some photos, and share them online; but keep their location a secret.