Syngrapha interrogationis (Linnaeus, 1758)

Host plants:
The caterpillars usually feed on Vaccinium species, especially Vaccinium myrtillus and Vaccinium uliginosum.

Habitat:
Syngrapha interrogationis is associated with acidophilous and coniferous, humid woodlands such as moor woodlands or montane spruce forests with Vaccinium undergrowth. It is also found in Vaccinium heathland in the mountains.

Life cycle:
The caterpillar hibernates and is fully-grown in May or early June. They live openly on mostly low growing Vaccinium. The moths are on the wing between late June and early September, according to the location and year.

Endangerment factors:
Syngrapha interrogationis is endangered through the intensification in forestry which results in ever darker, uniformous forests, locally also through tourism and usage of wind energy.

Remarks:
Syngrapha interrogationis has an holarctic distribution (North America, Europe, northern Asia). In Europe it is common in the north and becomes more and more local and restricted to mountains in the south where it occurs to the Pyrenees, middle Italia and Bulgaria.