Mastotermes darwiniensis — the Giant Northern Termite.

Evolutionary lineage.

Mastotermes darwiniensis is the only living species in family Mastotermitidae. Every other living termite (Kalotermitidae, Rhinotermitidae, Termitidae, etc.) descends from a more recent common ancestor. Mastotermes retains gut microbiology and morphological features from a much earlier branching point in termite evolution — it’s closer to the wood-eating cockroach lineage from which all termites descend. The practical consequence is broader dietary capability: Mastotermes can digest a wider range of materials than any other living termite.

Diet.

• Structural timber (hardwood and softwood)
• Plywood, MDF, particleboard, cardboard, paper
• Leather, plastic (especially soft PVC), rubber pool liners and gaskets
• Lead flashing, soft copper insulation, soft aluminium fly-screen frames
• High-lime concrete (slow but documented)
• Mulches, garden timbers, fence posts, retaining-wall sleepers

Mastotermes will chew through plastic irrigation tube to get to a wooden raised garden bed. It will eat the rubber gasket of an under-sink water filter to get to the wooden floor below. There’s a documented case (CSIRO, 1990s) of Mastotermes chewing through the lead sheathing of underground telephone cables, blacking out northern WA mining towns. This isn’t the same animal as a southern Australian Coptotermes inspection prepares for.

Colony structure.

Coptotermes colonies are centralised — one big nest (often inside a tree or stump), foraging tubes radiating out up to 100m. Find the nest, treat the nest, problem solved. Mastotermes colonies are diffuse — spread across 1–2 hectares with multiple satellite nests, no obvious centre, no diagnostic mound. There’s no “the nest” to find. This is why inspection patterns developed for southern Australia systematically miss Mastotermes presence in the Top End. A mud-tube-only inspection routine simply doesn’t see it.

Identification.

• Soldier: Larger than Coptotermes — 6–8mm body length. Head is rectangular, dark amber-brown. Mandibles are heavy, curved, with prominent serrations on inner edge.
• Worker: Pale cream-white, 4–6mm. Distinguishable from Coptotermes workers under microscope (5 tarsal segments vs Coptotermes’ 4).
• Alate (winged reproductive): Large — 25–35mm including wings, dark brown body. Swarm flights typically October–November after wet-season build-up rains.
• Egg cases: Unique among living termites — Mastotermes lays eggs in clusters held together by adhesive secretion, more like a cockroach than a termite. Diagnostic if found.

Treatment approach.

Baiting first, chemical second. Because Mastotermes colonies are diffuse, a perimeter chemical-soil barrier protects only the building footprint, not the surrounding colony. The colony continues to forage and will work around or through the barrier over time. Baiting systems (Sentricon Always Active, Exterra, Trelona ATBS) installed at 10–15m intervals around the perimeter AND along bushland boundaries do what chemical can’t: bait gets carried through the diffuse colony by foraging workers, the IGR toxin spreads via grooming, and the colony is eliminated.

For active Mastotermes infestation we typically combine: Sentricon Always Active perimeter + chemical-soil injection band + monthly monitoring during the wet-season build-up (September–December) and quarterly thereafter. Belt and braces. Standard southern Australia treatment (perimeter chemical only) is not enough.

• Treatment chemistry choice. Coptotermes and Schedorhinotermes respond identically to standard Termidor SC chemical-soil. Mastotermes needs higher injection volumes plus baiting.
• Inspection focus. If Mastotermes is present, focus expands to the full 1–2Ha around the building. If Coptotermes is dominant, perimeter + sub-floor focus is sufficient.
• Treatment intensity. Mastotermes is the most aggressive and broadest-diet termite alive — treatment must be both more thorough and longer-monitored than Coptotermes.
• Insurance. Some insurers respond differently to documented Mastotermes treatments because of the broader damage profile. Documentation matters.