Percnodaimon merula inhabits the rocky environments of New Zealand’s Southern Alps, where almost vegetation-free scree slopes appear to represent its optimal habitat. These slopes provide suitable conditions for all stages of the life cycle: sun-exposed stones offer warm surfaces for egg incubation and adult thermoregulation, deep spaces between rocks provide shelter for pupae against predators and protect adults at night and during periods of bad weather, while sporadic alpine grasses (Poaceae) serve as larval food plants. The species appears to occur wherever suitable scree habitat is present, suggesting that the extensive areas without records may largely reflect under-sampling rather than true absence. Remarkably, Percnodaimon merula is in many respects strikingly similar to Erebia pluto, a European alpine species occupying the same ecological niche in the mountains of Europe.
