Leptidea morsei (Fenton, 1882)

Host plants:
The larvae usually feed on Lathyrus niger, locally also on closely related other Lathyrus species.

Habitat:
Leptidea morsei is a typical inhabitant of open, light woodlands, especially warm, mesotrophic and mesophilous oak woodlands, where the host plant occurs in the understory. Oaks are light forest species which let more light through ther canopy than e.g. beech or marple. Leptidea morsei is also known from riparian woodland.

Life cycle:
This largest European Leptidea species usually occurs in very low densities and thus needs large habitats. The butterfly appears most often in two generations: the first from late April (sometimes already from mid-April) until mid-June and the second one between late June and August. In cool regions there may be a single generation in June/July only. Males patrol along forest tracks and other woodland edges. Oviposition usually takes place singly on the underside of a leaf of not too small plants. The larva develops on a single plant and does not change it. The decvelopment is fast with three larval moults only. Larvae on living plants which resulted in non-hibernation pupae pupated on the host plant without migration phase.

Endangerment factors:
Leptidea morsei is heavily endangered in eastern central Europe (e.g. E-Austria) due to abandonment of traditional forest management (e.g. mixed coppice, fuel wood), afforestation with dark forest species such as beech or maple and eutrophication. Leptidea morsei is listed in the annexes of the Flora-Fauna-Habitat directive of the European Union, but this would only be helpful if the resulting area management plans were proper translated in actual an sustainable field measures.

Remarks:
Leptidea morsei occurs from eastern central Europe (E-Austria, Czech Republic, Slovenia) eastward across E-Europe and temperate Asia to N-Japan. In Europe, it is principally a lowland species which does usually not occur above 1000m. In Asia, however, it reaches locally 2000m.