Large Tortoiseshell
Nymphalis polychloros
The Large Tortoiseshell is a striking butterfly belonging to the Nymphalidae family. Its upper wings are bright orange-brown with characteristic black spots and a dark margin that can feature bluish spots. It is closely associated with woodland edges, clearings, and old orchards, where its larvae feed gregariously on various deciduous trees. The species overwinters as an adult in hollow trees or buildings and is among the first butterflies to appear in early spring.
Details
Identification
Orange-brown ground color, four black spots on the leading edge of the forewings, dark margin with blue crescent spots (often faint), underside marbled grey-brown (bark camouflage).
Social behavior
Adults are solitary, while the larvae live gregariously in communal webs during their early stages.
Diet
Adults primarily feed on exuding tree sap and rotting fruit, less frequently on floral nectar (e.g., willow catkins). Larvae feed on the leaves of deciduous trees.
Spawning substrate
Twigs of deciduous trees such as willows (Salix), elms (Ulmus), poplars (Populus), or fruit trees.
Overwintering
Overwinters as an imago (adult butterfly) in sheltered locations such as hollow trees, cellars, or attics.
Ecology
Ecological role
Pollinator in spring; larvae serve as a food source for birds and parasitic wasps; adults are preyed upon by birds and bats.
Natural predators
Birds, bats, orb-weaver spiders, ichneumon wasps (parasitoids of the larvae).
Competitor species
Other nymphalids like the Small Tortoiseshell (Aglais urticae) or the Camberwell Beauty (Nymphalis antiopa) when feeding at sap sites.
Ecosystem service
Pollination of early-flowering woody plants.
Threats
Habitat loss due to intensive forestry, decline of elm trees (Dutch elm disease), removal of softwoods, and use of pesticides.
Scientific profile
Profile
Distinguishing features
Larger than Aglais urticae; features four black spots on the costal margin of the forewings (A. urticae has three). The ground color is a more yellowish-brown rather than bright orange. Legs are light-haired. Unlike Nymphalis xanthomelas, the legs of N. polychloros are dark brown to black, and it lacks the distinct white spots on the forewing costa (Source: Lepiforum, BfN).
Habitat
Open deciduous forests, forest edges, orchards, avenues, parks, and large gardens with mature trees. Prefers warm, sunny locations.
Protection & threats
Main threats
Decline of elms due to Dutch elm disease, intensification of forestry (removal of softwoods), loss of traditional orchards, and the use of insecticides.
Population trend
Highly fluctuating; on the early warning list (V) in Germany, regionally endangered (RL 3). In recent years, there have been signs of slight recovery in some regions.
Conservation measures
Preservation and promotion of softwoods (willows, aspens) in forests, protection of elm stands, maintenance of traditional orchards, and avoidance of pesticides near forest edges.