Lasiocampa quercus (Linnaeus, 1758)

Host plants:
The caterpillars feed on many herbs and shrubs or dwarf shrubs, especially Salix, Vaccinium, Calluna, Alnus, Rubus and Fabaceae.

Habitat:
In the lowlands, Lasiocampa quercus inhabits mostly heath moors, bushy grasslands near the woodlands, open riparian forests and other woody areas. In the mountains Lasiocampa quercus is one of the most common and widespread species upt to about 2300m above sea level, especially in the dwarf shrub belt.

Life cycle:
Lasiocampa quercus has a very variable life cycle with two main lines:
In the plains the moths fly in one quite late generation per year in July and August. The young caterpillar overwinters and can be found on shrubs and lower trees such as willow and alder in the autumn (September, October) and early spring (March-April). But the true hibernation apparently occurs on the ground. Pupation takes place in June in a cocoon in the litter layer, and rarely also increased.

In the higher mountains, the cycle is generally at least biennially. First hibernates the young to half-grown caterpillar, then in the second year the pupa. After the first winter the then larger caterpillars are observed quite frequently. Next spring, the butterflies fly very early between late May and July (as in early June at 2000m asl in the Silvretta area), sometimes even later.
Whether there also occur twice overwintering caterpillars and how many pupae can hatch without hibernation or how many pupae hibernate two times remains to be investigated.

Endangerment: regionally endangered or decreasing

Endangerment factors:
In the lowlands Lasiocampa quercus is in decline due to the destruction of open, sunny shrub formations and increasing dark forest management. In the Alps, Lasiocampa quercus is still very common and not threatened.

Remarks:
The males are diurnal, in the mountains (whether also in the lowlands?) also the females (some personal observations).

Lasiocampa quercus is widespread in most of Europe and many parts of the temperate to cold Asia, in Europe particularly common in the mountains and in Scandinavia.