Scientific name: Formica rufa
Size: Up to 11mm long
Distribution: Found throughout the U.K.
Months seen: February to October.
Life Span: The Queen wood ant can live for more than 10 years
Habitat: Woodlands and heathland.
Food: Invertebrates and honeydew from aphids
Special features: Southern wood ants (Formica rufa) are the largest ants found in the UK. They are social insects which live in colonies numbering up to 500,000. The communal nests are made out of dead leaves, stones, pine needles and twigs.
The nest can be up to 100cm high, and inside there is a labyrinth of tunnels leading to hundreds of different chambers. Each chamber serves a different purpose. Some are living quarters, some are food stores, some are cemetaries for dead ants.
The material on top of the nest acts like a thatched roof, preventing the ingress of rainwater. The 'roof' is also slightly flattened on the southern side. This flat side acts like a solar panel, absorbing more of the suns heat energy. The workers can also open and close the many entrance holes to regulate the temperature inside the nest.
There are three types of ant in the colony; workers, males and queens.
The workers (as the name suggests) go out foraging for food, look after the young (eggs, larvae and pupae) and also perform any repair work necessary on the nest. They are all females, and they do sometimes lay eggs which are used as food.
Columns of workers go out each morning on well known hunting trails which radiate from the nest. As they go, they leave a scent trail behind them for others to follow, and to retrace their steps back to the nest.
Southern wood ants have powerful mandibles for biting and immobilising prey, and they are also equipped with a chemical weapon. They can spray formic acid from the end of their abdomens. They are able to squirt the acid quite accurately over a distance of 5cm or more. The ants use this weapon to subdue their prey and to protect themselves from predators.
The male ants, which are winged, do not work. Their function is to mate with a queen. On a warm, dry summer day they fly up out of the nest to mate. The males die after mating, and after the females land they bite of their wings and start a new nest in a new location.