Dampwood Termites

Brief:

Dampwood termites, Termopsidea, are always associated with damp, decaying wood, usually in the form of fallen logs in the forest, but may sometimes be found in decaying wood in buildings or fences. They depend on the moisture in the tree and mostly have galleries in the softer growth rings of the tree. They do not form a large central colony but live in many small independent groups or colonies in the wood.

The distinction between ‘dampwood’ and ‘drywood’ termites is an area of much confusion. The term ‘dampwood termite’ is often reserved for the Termopsidea, however three genera in the family Kalotermitidae (Neotermes, Glyptotermes and Ceratokalotermes) are considered dampwood termites.

Family Termopsidae
Stolotermes victoriensis and Porotermes adamsoni occur in the highland and coastal areas from southern Queensland, NSW, Victoria and South Australia.

Family Kalotermitidae
The ringant termite, Neotermes insularis, has one of the largest soldiers of all Australian species. Soldiers are 9-15mm long with strong mandibles that turn upwards slightly. Its distribution extends from Victoria to the Torres Strait and across to Darwin in forests within 80 km of the coast. Colonies are founded by alates in branch stubs and the dead wood of living trees.

Entrance into the tree may occur at almost any height and galleries may eventually extend throughout the tree. Mature colonies may be populous, with several thousand individuals. The galleries are usually clean, sometimes with accumulations of discrete moist faecal pellets. The concentric gallery system in the softer wood of each growth ring is responsible for the common name. Ringant termites are pests of some commercial eucalypt species.

Glyptotermes, Kalotermes and Ceratokalotermes form small to sometimes large colonies in and around dead wood in species of Eucalyptus and can cause damage in standing power poles.

Glyptotermes occur along the coast and highlands from Queensland to NSW, Victoria and South Australia, whilst Kalotermes occur mainly along coastal and highland regions of NSW and Victoria, with Ceratokalotermes being found along the eastern coast of northern Queensland down to southern NSW. 

Habits

Cellulose found in plants, is the basic food requirement of all termites, and all types of plant material can be damaged. Most termite species eat grass and other surface vegetation and have an important role in maintaining soil fertility. They recycle nutrients, in particular nitrogen, which is essential for healthy plant growth. When termite mounds erode, the soil particles rich in nutrients such as calcium, magnesium and potassium are washed into the soil from the mound to become available for plant growth. Termite galleries improve soil structure, and assist water entry and storage in soil; the galleries thereby reduce surface rainwater runoff and subsequent soil erosion.

Other termite species infest timber and particularly timber which is in an early state of decay by wood rotting fungi. Some species of timber are resistant to termites, but none is entirely ‘termite proof’. Termites will often damage materials they cannot digest, for example, plastics, rubber, metal or mortar. Primarily, this damage occurs when the indigestible items are encountered during the termites search for food.

Some termites forage for food by means of subterranean galleries or covered runways, which extend from the central nest to food sources above or below ground. The gallery system of a single colony may be used to exploit food sources over as much as one hectare, with individual galleries extending up to 50 m in length for most species. In the case of the giant northern termite, individual galleries may extend as far as 100–200 m. Apart from grass-eating species that forage in the open all termites remain within a closed system of galleries, devoid of light. The only exceptions are during a swarming flight, or when repair or new construction is occurring. The advantages to the termites of this closed system are twofold. They are protected from natural enemies such as ants, and they gain a measure of protection from temperature and humidity extremes. Termites have a thin external covering and have relatively little resistance to drying out.

Habitat

Termites build various types of nest. Some termites have a completely underground existence, apparently without a central nest. Others build a central nest in the soil, or in dead or living trees; any economically important termites build nests of this type. Still other species attach their nest to a tree but maintain a soil connection via galleries running down the surface of the trunk. A termite mound is the most familiar form of termite nest.

Mounds are often of very distinctive form, and their size and shape vary from hardened, flat areas to the tall, columnar structures of the spinifex termite Nasutitermes triodiae in northern Australia, which may be more than 7 m high. Typically, each species builds a characteristic mound, although there may be geographical variation in the size and shape of the mound within species. In the mounds of Coptotermes the outer wall is hard and built of soil and the inner region is generally composed of woody faecal material (carton) and soil.

Threats

Although the coastal belt and northern parts of the country are generally regarded as high hazard areas for subterranean termite infestation, species, which damage timber-in-service, occur throughout mainland Australia. In practice, any structure containing wood is exposed to possible subterranean termite infestation whether in the business heart of a city, in the suburbs or out in the country, unless protective measures are taken.

Prevention

Others

Photos and information are provide by Scott Kleinschmidt - BASF.

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