Over 1000 named species in Australia. Examples are Bulldog or Bullants (Myrmecia and Odontomachus, including Jack-jumper or Jumper ant, M. pilosula group); Meat ants (Iridomyrmex purpureus group); Sugar ant (Camponotus consobrinus); and Green tree ant (Oecophylla smaragdina). Only a few ant species are pests; three introduced ones are Argentine ant (Linepithema humile) and two Fire ants (Solenopsis geminata and S. invicta).
Most people can recognise an ant, although some other insects and spiders mimic and resemble them. There are 3 castes, of which the wingless and usually sterile female "worker" caste is the typical and most commonly seen one. The other 2 are queens (fertile females) and males. Queens usually closely resemble workers, but may be larger; they initially have wings which are later lost. Males are quite wasp-like, although they cannot sting. Ants vary in length from about 1 to 30mm or more and are mostly black, brown, red or yellow, or a combination of these.
Australia-wide, including Tasmania, in all terrestrial habitats. Bushland areas have numerous coexisting species. Fewer species can live in suburban gardens and buildings.
Ants are social insects forming colonies varying in size (depending on species) from a dozen or so to many thousands. A colony usually occupies a nest. Habits, behaviour and nest sites vary widely between species. Many are scavengers and/or have varied diets, others are specialist seed-eaters or predators. Winged males and queens leave nest on mating flights, after which mated queen loses wings and establishes new colony.
Some ants are stinging pests, notably Bulldog or Bullants. Venom of Jack-jumper or Jumper ant can cause severe allergic reaction. Others, such as Meat ants and Green tree ants simply bite. Some ants are a nuisance pest when they make mounds or invade homes and food. Three introduced species, Argentine ant, Fire ant and Crazy ant (Anoplolepis gracilipes) are both nuisance and environmental pests. Native ant species play an important part in natural food webs.