Zygaena trifolii (Esper, 1783)

Host plants:
Lotus corniculatus and - most commonly - Lotus uliginosus

Habitat:
Primarily Zygaena trifolii inhabits wet meadows, fens (often very small remnant habitats) and ditch verges. Farther north in Central Europe it is also found in dry grasslands (according to literature).

At Schwäbisch Gmünd (Southern Germany) Zygaena trifolii appeared numerously in 2010 in a road embankment that had been sown with grasslands species about 6 years ago in the north of the city, where also occur Zygaena filipendulae, Cupido argiades, Polyommmatus semiargus and Hadena perplexa. Unfortunately, in the next few years the senselessly planted trees will destroy the habitat again.

Life cycle:
I found half-grown caterpillars in the northern foreland of the Alps near Memmingen in mid-May together with mature larvae of Boloria eunomia. Generally they are fully-grown in June (many observations in southern Germany). The moth flies in July and August. Zygaena trifolii uses almost all available flowers, but particularly Lotus uliginosus, Betonica officinalis and Cirsium. This species can overwinter as a caterpillar more than once as it is the case with most Zygaena.

In southern France (Mediterranean coast near Perpignan) I observed a few individuals in mid-October 2013 which should belong to a partial second generation. This also occurs in Spain.

Endangerment: endangered

Endangerment factors:
Zygaena trifolii can reproduce in rather small wetlands. But these are particularly vulnerable to eutrophication (buffer areas needed!), succession and neophyts such as Solidago canadensis. In addition, such habitats are often incorporated into fields and meadows, misused as deposits for timber or afforestated.

Remarks:
Zygaena trifolii is easily confused with Zygaena lonicerae.
The distribution is southwestern European (Atlanto-Mediterranean type). The moth occurs from Northwest Africa across the Iberian Peninsula and France to England, Germany, Poland and Denmark. In Austria it is only found in the west (Vorarlberg). In southern Italy there are apparently small populations in Sicily.