Termites

Termites (also called white “ants”) are only a few millimetres long but they are the mound builders of the soil animal world. However, termites and ants are quite different animals. Similarities are only in their social behaviour (they both live in communities of many individuals and castes) and their nest building activities. Termite mounds occur in most areas of Australia though they reach their greatest glory in the semi-arid regions where they can be 6 metres high.

Mound builders are only one type of termite. Eighty percent of Australian termites build their nests underground. There are others that live in the heartwood of trees and eat out the centre to form a hollow “pipe” filled with termite excreta or “carton”. The wood eaters invade houses and cause damage to timber.

Termites are insects and are almost colourless as they live in the dark of the mound, the soil or their covered foraging galleries and don’t need a coloured skin to protect them from the ultra-violet light of the sun. They are social insects with many different types (or castes) living in the same mound and performing different jobs. The fertile king and queen produce all the termites in the colony. The blind, wingless, sterile workers forage for food and return to the nest to feed other termites with a part-digested meal from their own mouths. They also excavate soil and build the nest. Soldiers protect the nest from invaders and predators but are still blind and wingless. Winged castes fly out of the old colony to form a new one. Soldier termites can have powerful jaws to repel invaders or they can have a pointy snout (see termite in the picture) through which it spurts a sticky, repellent chemical.

Termites are feeders on dead organic material such as wood and old trees and grass leaves but some bring fungi back to the nest. Termites live in most areas of Australia but particularly in the dry areas where they take over the role of earthworms as decomposers of organic materials in these dry soils.

Termite mounds or nests are formed as they tunnel through the clay subsoil soil, making their galleries (which can extend up to 100 m from the nest and be several metres deep) and depositing the excavated diggings onto the the mound.

Their feeding galleries extend out from the nest and allow the termites to scurry about avoiding the light, and collect dead organic material to take back to the main nest. Termites are more soft-bodied than other insects and need to maintain a relative humidity of around 90% in the nest. They can control the environment in the colony – a sort of air-conditioning – by opening or re-sealing entrances to the nest as climatic conditions change. Termite nests have many functions. Nests protect them from extremes of environment – heat, cold, dryness, rain – and also provide a refuge from predators such as echidnas.

If the soil is flooded, mound-builders can retreat to the upper regions of their home.

Wood-feeding termites can make their nests entirely within the tree and connect with the soil with runways inside the tree. Other termites build nests on the outside of the tree with covered foraging galleries sometimes seen connecting their tree trunks to the soil.

This fallen tree was rotten to the core! The crumbly material inside the tree trunk is digested wood or termite excreta often with a honeycomb appearance. This excretal material is called “carton” perhaps due to its similarity to a corrugated-cardboard carton.

A great building material! Termites cement soil particles and faecal material together with saliva to make the aboveground mounds and it is an extremely hard, well-compacted material. Termite mounds have been used to construct roads, tennis courts, house bricks, earth floors of buildings, cow yards and cricket pitches in outback Australia.