You find it by accident. You are splitting a rotting log, looking for firewood or perhaps the large, white larvae of the huhu beetle. Instead, you find a black stalk rising from the head of a dead grub. This is the Huhu Grub Fungus. It does not announce itself. It waits in the dark, consuming its host from within. The fungus is specific. It targets the larvae of the huhu beetle, Prionoplus reticularis. It does not attack other insects. It does not attack humans. It is a specialist, requiring a precise host to survive. This fungus is parasitic. It does not decompose dead wood directly. Instead, it feeds on living tissue, specifically the larvae of the huhu beetle. In doing so, it regulates huhu populations. It is a natural check on abundance. Without it, huhu numbers might surge, affecting the rate of wood decay. The fungus enters the larva through the skin. It grows inside, consuming the soft tissue. The larva dies, but its exoskeleton remains intact, a hollow shell filled with white mycelium. The fungus takes control. It directs the larva to remain in place. Then, it stops. It waits for the right moment. The fruiting body is a slender, black stalk that emerges from the head of the buried larva. It rises through the wood, breaking the surface like a thin, dark needle. The stalk is topped with a fertile head, where spores are produced. It is small, rarely exceeding five centimetres in height. It is easily overlooked, blending into the dark forest floor. It appears in late summer or autumn, when the huhu grubs are most active. The Huhu Grub Fungus is found throughout New Zealand, wherever huhu beetles and suitable forest conditions exist. It is not common. It is rarely seen, as most of its life cycle occurs beneath the bark. Its presence is a sign of a healthy, functioning ecosystem. Where it grows, the balance between predator and prey is maintained. It is an indicator species, a biological signal that the wood is alive with activity. Threats are minimal. The species is widespread but elusive. However, it is sensitive to changes in forest structure. Logging removes the old, decaying wood that the huhu beetles depend on. Without hosts, the fungus cannot survive. Recovery is slow. The fungi wait for the conditions to return. They do not rush. It carries on.