How important are termites in Australia anyway?
In the beginning…
…there were no termites. There was no wood either. When plant life started to compete with neighbouring plant life for light and the most successful plants strengthened their stems to get even higher by becoming woody, a sub-group of cockroaches saw a new opportunity. This subgroup turned communal and specialised. Then an even more specialised group within that tribe decided that when the woody-stemmed plants fell over dead on the forest floor, they shouldn’t let it go to waste. They developed the physical equipment and the lifestyle to find this food and eat it.
This happened around 300-400 million years ago and these wood-eating termites have been getting better at their job, adapting to the new opportunities but still within the tried and true guidelines they’ve found to work for them.
There will be some references made to the non-pest species during this book but essentially the storyline is about the wood-eaters and the humans who studied them and developed methods and products to manage termite threats to our structures.
So How Important are Termites in Australia?
There are almost 300 species of termites in Australia and almost 3000 species worldwide. They are highly social, forming colonies which are often very large, with marked division of labour, and which present an intriguing complexity of biological questions
(Watson and Gay, 1983).
Only about 25 of our species are considered to be economically important as pests of trees and crops, timber-in-service, timber products and building and construction materials. Most of these species belong to the genera Mastotermes, Coptotermes, Heterotermes, Schedorhinotermes, Nasutitermes and Cryptotermes.
Many termites have tiny, single-celled organisms known as protozoa in their intestinal tract. These flagellated protozoa are essential in the conversion of cellulose to soluble sugars that can be used by the termites; they produce an enzyme that digests the cellulose. Protozoa in many species, or bacteria in others, are transferred from termite to termite, by contact during the grooming process (Gerozisis et al., 2008).
Termites have a cryptic manner of living; they live in a hidden system of passageways, either entirely in the wood in which they feed or partly within the wood and partly within the soil. They require a high humidity to avoid desiccation and therefore they seldom emerge into the open air. At certain times of the year, depending on the species, some members of the colony develop wings and change from pale nymphs to darker reproductives. These are the potential kings and queens of future colonies.
Some knowledge of the habits of these few species will be useful in the determination of hazards.
The Incidence of Termites in Australia
In Australia, the annual cost of repair of damage to timber-in-service caused by termites has been estimated by Archicentre (the building advisory service branch of the Australian Institute of Architects) to be $780 million per annum (Archicentre, 2016) which is more than the costs for fire and storm damage combined. Once a home, building or structure is infested by termites, eradication can be difficult, and may be a long and drawn out process.
An infestation is often not detected until it is so severe that structural damage has occurred and substantial repairs and material replacement are required. This, together with restitution costs and time can put the owner under severe hardship. If not treated properly, the nest may not be eradicated.
Once disturbed, termites may immediately vacate and simply feed elsewhere. Inadvertently, therefore, unprofessional eradicative treatment of termite infestations can have severe repercussions for both the homeowner concerned and those of any surrounding properties. The ill-informed homeowner may believe that the termite infestation has been eradicated when in fact it has not. If left unchecked and untreated, the colony of termites responsible for the infestation will inevitably focus its attack on timbers elsewhere in the building or on surrounding properties.
Treatise on the Isoptera of the World
Fortunately, the comparative significance of our termites can now be more readily understood with the publication of a ‘Treatise on the Isoptera of the World’ (Krishna et al., 2013). There are 3105 living and fossil species, classified into 12 Families and 330 living and fossil genera. Of the 2,937 living species of termites worldwide, less than 10% – 273 are in Australia.
However, we are by no means lacking in publications about our termite fauna. In the bibliography of nearly 5,000 references in the world treatise, covering virtually all aspects of termite taxonomy and biology up to December 2011 (excluding control literature), 335 are by Australian authors and/or about Australian termites.
As taxonomic studies of Australian termites have been almost exclusively the province of a small number of professional entomologists, it is of interest to note that of those 335 publications, CSIRO ‘Taxonomic Termiteers’ authored or co-authored more than 200 as follows: Tony Watson – 62, Frank Gay – 41, Michael Lenz – 32, Leigh Miller – 28, Gerald Hill – 26, Theo Evans – 12, plus Walter Froggatt – 6, Charles French – 1.