Map butterfly

The Map butterfly (Araschnia levana) belongs to the Nymphalidae family of butterflies. It is widely known in entomology for its remarkable seasonal polyphenism, where individuals of the spring generation appear reddish-orange, while those of the summer generation are predominantly black with white bands.

The larvae feed primarily on stinging nettle (Urtica dioica). While not a major pest in industrial agriculture, the species can become a nuisance in medicinal herb gardens or nurseries where nettle is cultivated as a crop, as the larvae are gregarious feeders capable of defoliating entire patches of host plants.

The biological cycle consists of two or occasionally three generations per year. Overwintering occurs in the pupal stage. Females deposit their eggs in chains on the underside of leaves. Once the larvae hatch, they remain in groups, feeding voraciously and progressing through several instars before pupating on the stems or nearby structures.

The damage caused by Araschnia levana includes skeletonization and complete consumption of leaf tissue. This significantly reduces the photosynthetic area of the plant. In the context of medicinal herb production, such damage directly translates to reduced yield and diminished quality of the harvested biomass.

Effective management strategies include cultural practices such as regular scouting and physical removal of egg clutches or larval clusters. In instances of high infestation, biological control using Bacillus thuringiensis sprays is highly recommended as it targets the caterpillars specifically while minimizing environmental impact on non-target species.