Ants are one of the most regular and crucial group of insects. In 1985 Taylor and Brown categorized the Australian fauna and classified them in 9 subfamilies, with 95 genera and an approximate total of 4000 species. The chief characteristic of ants are their waist. It is usually made up of one or two knobs (which are the first one or two segments of their abdomen) instead of the single petiole of the hymnopterans. The antennae have a unique elbow, with the scape almost as long as the segments past the elbow, with protruding mandibles. Ants reside in colonies made up of several castes and sub castes: winged females, winged males and numerous sub castes of workers. Colonies generally have hundreds to several thousand individuals, though the amount is less than 100 to more than a million. Winged females and males only appear during times that are suitable for mass mating flights. The male ends up dying after mating and the females shed their wings and generally start a new colony, or sometimes end up being the part of an existing one. To start a colony the female lays a small number of eggs and then feeds the larvae till they are mature.
These first workers then own up to the function of nest building and look after this first queen who’s only remaining purpose is to lay eggs.
The worker sub castes consist of the worker minors who perform nest building, food foraging and nursery care; workers with big heads called soldiers defend the nest. Certain species have a sophisticated sub caste named repletes, which play the role of being storage vessel for the colony nectar supply.
Ant nests are generally in the ground, but you can also find them in trees and even among silk-joined leaves in the green tea ant, Oecophylla smaragdina, which dominates in the tropic region. The infamous Australian ants are aggressive stinging bull ants, which belong to the large endemic genus Myrmecia. Amid the ground nesting ants, the meat ants, Iridomyrmex are the famous red and black scavengers which dominate the more arid regions. One of the biggest genera is Polyrhachis, which consist of metallic species and the ‘golden-bum’ ants.
Ants have a diverse diet that consists of predators and scavengers, plant eaters, fungus eaters and other specialties or combination of all of these. Certain species of plants, especially in the tropics share a special bond with a particular ant species. The so-called ‘ant-plants’ have special chambers that is colonized by ants, and it also feeds the ants in return for protection from herbivores. Another ant relationship comprises of specialized species in eight other insect orders called myrmecophiles. These reside within the nests of ants either as predators or scavengers, or are actively stimulated by the ants as they excrete sweet secretions favored as ant food. Certain ants actually ‘farm’ aphids, scale insects and some butterfly larvae to meet this purpose.
The following hymenopteran groups, the sphecid wasps (formerly superfamily Sphecoidea) and the bees (superfamily Apoidea), are now considered as a part of one group under the umbrella of the family Apoidea.