Calamia tridens (Hufnagel, 1766)

Host plants:
Grasses, on the eastern Swabian Alb especially Festuca ovina agg. (Festuca guestfahlica).

Habitat:
Calamia tridens is a typical inhabitant of warm nutrient-poor grasslands on lime or sand. These mostly show open ground spots, stones or rocks.

Life cycle:
The eggs overwinter. The caterpillars live in a slight webbed shelter in the center of the Festuca-clumps. I found young to half-grown caterpillars in late May and in June, especially at the hottest spots in dry limestone juniper grasslands. At the same places, I also observed larvae of Hesperia comma. I observed there mature larvae in July (9. July 2013). The moth (flight period mainly in the second half of July and in August) feeds often during the day on thistles like Carduus acanthoides or rests on the ground or in the bushes. I have beaten an adult out of a oak tree in 2m height (all observations in eastern Swabian Alb).

Endangerment: strongly endangered

Endangerment factors:
Calamia tridens is threatened and has already been pushed back severely by abandonment of traditional extensive grazing (transhumance) and other extensive grazing systems, and by eutrophication, agricultural intensification and partly overbuilding (e.g. in the Upper Rhine Valley).

Remarks:
Calamia tridens is still represented relatively well e.g. on the eastern Swabian Alb. In Valais I found moths quite often up to about 2000m asl on steppe slopes.

The overall distribution ranges from Spain across large parts of Europe (except in the Far North and in some southern regions) to Central Asia.