Olwen Dewhirst of Dunedin asks :-

I found a large ant in the roots of a Clivia from Tauranga obtained more than five years ago. Is it unusual being so large and does it bite? Is it common, is it strange for Dunedin, and is it normally so long-lived?

Warwick Don, an entomologist at Otago Museum, and author of “Ants of New Zealand”, responded.

The “large ant” is a queen of a native ant, Monomorium antarcticum or “southern ant”. Diagnostic features visible in the photo are its size (about 10 mm; workers are about 3 mm long), short antennae (as compared with a worker), and two nodes in the narrow waist, placing it in the subfamily Myrmicinae. In addition, the middle region of the body is bulky, a characteristic of the female reproductive caste in ants.

Typically, an ant colony comprises one or more egg-laying queens and wingless workers. Winged reproductives (males and females) fly from the nest in a nuptial flight (or swarm), during which mating takes place. The fertilized females drop to the ground, bite off their wings at the base and search for a suitable nesting site. The males, their single function accomplished, either perish from exposure or are eaten by predators such as birds, as are many of the females.

Queen ants can live for several years, unlike the workers (a matter of weeks). Her jaws are strong enough to remove her wings (not required in the nest galleries), so it is possible she may be able to inflict pain if provoked.

The southern ant is our most ubiquitous ant species, being found throughout all three main islands and on offshore islands as well. Although somewhat inconspicuous to the casual observer, it is by far the commonest ant in Dunedin.