Isoptera: termites

Characteristics
Termites are small to medium sized insects ranging form 3-20 millimetres in body length. These insects are not often seen although evidence of their presence is observable in the large mounds they construct or the damage they do to wood products and structures. Termites can be distinguished by the following features:

• Pale, elongate body

• 2 pairs of membranous wings of equal length. Wings are present in reproductive castes only and shed after mating

• Mandibulate (chewing) mouthparts

• Antennae about the same length as the head

Termites are social insects and live in colonies consisting of a queen, sterile workers and soldiers and winged reproductive males and females known as alates. Termites are often known as 'white ants' however these insects are very different from those in the order Hymenoptera to which ants belong.

Coptotermes species are widely distributed across Australian and are most easily recognised by the milky substance that the soldiers produce when disturbed. All Coptotermes species form large colonies which likely contain millions of individuals. Colonies may be found in nests under the ground, in tree stumps, in hollow trees, in living trees or in conical mounds above the ground. All Coptotermes species are wood feeders and some are known to cause severe damage to living trees and other wood including that utilised by humans. Coptotermes acinaciformis is found in all states in Australia but only builds mound nests in the northern and south-west areas of its range.

Life Cycle
Termite colonies produce a reproductive caste when they have reached a certain size. These individuals consist of male and female termites that on warm humid nights usually fly away from the nest to mate and begin new colonies. After mating, individual pairs of termites build a new shelter to house a small number of eggs which will develop into the first workers and soldiers of the new colony. When this first brood is able to begin enlarging the new nest and feeding the queen she will begin to lay eggs almost continually rapidly increasing numbers in the colony. The nymphs of termites resemble adults. A colony of termites may consist of over a million individuals.

Feeding
Termites feed on a wide variety of plant material, which may include wood, bark, leaves, grasses, fungi, humus or the droppings of herbivores. Some species forage on the surface at night collecting grasses which they take back to be stored in the nest. Others more commonly avoid all light and build protective tunnels to travel between the nest and their food source.

Habitat
Termites are found throughout Australia and are usually detected in natural habitats by their conspicuous earthen mounds, which may be as high as 3 or 4 metres in some areas depending on the species. Some termites build smaller earthen nests in trees while others construct a complex network of subterranean tunnels connecting larger galleries. Wood dwelling species do not build nests but live within the galleries they have excavated in the wood they feed on.

Mastotermes darwiniensis (the giant northern termite) is a large endemic species which lives in nests in trees and logs. In native environments, populations are generally small but in built up areas nests can become very large. In these situations M.darwiniensis becomes a serious pest of wood including living and dead trees, other wood products such as building material and even crops. M.darwiniensis is confined to the tropics but other pest species are found elsewhere throughout the country.