Termite damage at Te Aroha house rare, says insect expert
When it comes to identifying New Zealand drywood termites it pays to know your excrement, according to Bug Man Ruud Kleinpaste.
The hexagonal-sided droppings are the easiest way to differentiate between Australian subterranean termites and their Kiwi drywood cousins, he said.
His comments come after a Te Aroha house riddled with native termites hit headlines.
Tobi Lawton and Sarah Lee bought a house with their life savings last December but it was so damaged by the insects it had to be demolished.
That level of damage from the NZ drywood termite (Kalotermes brouni) was almost unheard of, insect experts say.
"The damage is usually quite small and localised. Obviously not in this case . . . Hell's bells, if you're going to have to build the family a new one [house] it's obviously in a pretty bad way," forest entomologist John Bain said.
Even as an insect expert, he didn't check for termites when he bought his last house and said it didn't cross New Zealanders' minds because it generally didn't need to.
The Te Aroha case was the most extensive damage from native termites he'd ever heard of, and he said it must have happened over "decades rather than a few years".
But drywood termites were hard to pick up because they never broke through the exterior, he said.
"You don't know until you try and drive a screwdriver or something. The wood looks OK from the outside. They're cunning little sods. They can completely hollow out that bit of timber and just leave a very thin veneer around the outside."
New Zealand has three native species of termite, which Bain said was few compared with countries such as Australia - which had hundreds.
Drywood termites need dampness to get started - then they can "persist" in quite dry timber, Bain said.
But damage in houses was normally small and near something like a leaking tap, he said.
Native drywood termites tended to have small, localised colonies in the houses where they were doing damage, he said.
Australian subterranean termites remained in contact with a big nest structure outside and built tunnels to connect that with objects of interest.
These visible tunnels made it easier to detect them, he said.
And while Lawton and Lee are less than delighted with termites, the Bug Man Ruud Kleinpaste thinks they are fascinating and calls them the "undertaker squad" of dead timber.
"They were invented . . . to start off the decomposition of fallen trees," he said.
"They just look at your house and say ‘look, there's a dead piece of Rimu here. Don't worry about a thing - I'll clean this up for you real quick. Here's my business card, I've been doing this for five million years."'
The insects are also smart builders which effectively create natural air conditioning for their colony by selecting an area with airflow for a "chimney effect" which keeps the temperature and relative humidity constant, he said.
He advised homeowners to keep their houses dry and avoid prolonged wetness or dripping gutters or taps which splashed on the weatherboards.
Types of termite
NZ drywood termite, Kalotermes brouni
Nest inside dead wood they attack
Leave hexagonal-sided droppings
Damage tends to be localised, but unlikely to be detected until timber is seriously weakened
Australian subterranean termite
Large outdoor soil nest structure
Build tunnels from a mud-like material between nest and exterior
Do not leave faecal pellets in the wood
Almost always linked with imported Australian hardwood, eg railway sleepers
Both About 5mm long
Timber attacked is often reduced to a series of galleries, with paper thin partitions between them