Thatching Ants are a species of Formica ant that often build huge nests. Their nests are usually large mounds out of sticks, leaves, grass, and pine needles. They also can nest in decaying logs.
They are considered both an annoyance and a benefit for various different reasons. The annoyance comes because they can severely damage landscaping and can wreak havoc on some fruit trees or saplings, but a benefit because they do more than their fair share in controlling other insects.
They are social insects that live together in large colonies. They also bring in aphids to their colonies, so that they can have the sweet honeydew that is produced by them. The thatching ants will provide food for and protect the aphids from their own natural predators, thus creating an overabundance of aphids in some cases.
These ants are either all black or red and black in color and measure up to 1.5 cm long. The reproductive ants referred to as males and queens, are the only winged thatching ants. Worker ants have no wings.
Thatching ants should be avoided by humans when possible as they have a very painful bite and will spray the bite with an acid that causes a burning sting. Ant colonies start with a single queen ant who will build up her colony from hundreds to thousands as she reproduces.