(Müller, 1764)
Large Heath
Description:
The Large Heath inhabits raised bogs, wet heaths, swampy habitat and wet grasslands, often occurring on quite rough vegetation. As a consequence of land drainage remaining habitat patches are often small, and populations they contain very small indeed, making them difficult to detect. However, in a vast peatland, the Large Heath can be common, and the butterfly can be seen flying back and forth between wet patches with the food plants and the drier edges of the bog where nectar plants are growing. There is a lot of uncertainty about the identity of the food plants. Probably, there are regional differences in their use. Cotton-grass (Eriophorum vaginatum) is certainly important, but other Eriophorum species, beak-sedges (Rhynchospora spp.), fescues (Festuca spp.), Purple Moor-grass (Molinea caerulea), and a few sedges (Carex spp.) are also named.
The female deposits her eggs singly on, or in the neighbourhood of, the food plant. The caterpillars hibernate in the third or fourth larval instar, hidden in tussocks of grass. They try to find a position in the vegetation that offers protection from predators above, and from high winter water levels below. They also pupate in the tussocks of the food plant.
The Large Heath has one generation a year.
There are many regional subspecies, that are distinguished by the degree of development of the eye-spots.
Habitat:
Raised bogs
Fens
Blanket bogs
Humid grasslands
Similar species:
Coenonympha pamphilus
Coenonympha glycerion