Host plants:
The caterpillars live polyphagous in the herb layer. Galium is a rather often hostplant.
Habitat:
The most common is Diacrisia sannio found in seasonally dry, higher growing grasslands (e.g. juniper heath). It also occurs in clearings, fens and similar habitats. It lacks very hot and dry, low growing places and throughout the settlement area and cultivated land, where no natural rest areas remain.
Life cycle:
The half-grown caterpillar overwinters and is found in the fall often exposed to old seed heads, blades of grass, etc. In May, the caterpillar is fully-grown. Moths are often encountered in June/July. In lower and warm habitats Diacrisia sannio often has a partial second generation in August.
While the males are easily flushed in the sunshine and resettle a few meters further, the the languid females are seen much less frequently.
Endangerment factors:
Even this relative undemanding species is declining in many regions due to darkening processes in forests and the decreasement of extensive, little cut areas. But it is also found on clearcuts and not seriously threatened in particular in areas with many extensively managed grasslands as for example in the Jurassic landscapes of Southern Germany..
Remarks:
Diacrisia sannio is widely distributed in Europe (but missing in the far south) and Asia.