Euthrix potatoria (Linnaeus, 1758)

Host plants:
The larvae feed on Poaceae and Cyperaceae. They are observed most often on Phragmites, Phalaris and Calamagrostis.

Habitat:
Euthrix potatoria inhabits wetlands, wet clearings, open woodlands, stream margins, fallow land and similar places.

Life cycle:
The eggs are laid on perennials, grasses or bushes in the habitat. I found eggs on willows of 1m in height as well as on Lythrum near the ground (in a garden). The half-grown caterpillar overwinters free on stems or branches. I found them occasionally resting on sallows (up to over 2m in height) while searching for Apatura. In spring, it is fully-grown in late May or June and can be observed resting on all sorts of plants or litter during the day. The moths fly from late June to August.

Endangerment: regionally endangered or decreasing

Endangerment factors:
Euthrix potatoria is in decline due to the disappearance of reedy marshes and wet forb communities and due to the often nonsensical mowing of all road and river edges. But it is also found in moist clearings etc., so that it is still not severly endangered in its strongholds. Euthrix potatoria does not tolerate mowing!

Remarks:
Euthrix potatoria lacks wide (dry) areas, such as large parts of the Swabian Alb. In the northern foreland of the Alps, however, it is widespread.

Euthrix potatoria occurs from Northern Spain across Central Europe and temperate Asia to the Pacific. In Europe it misses in the southern Mediterranean region as well as in Central and Northern Scandinavia.