The larvae feed on Plantago species, Scrophulariaceae like Veronica and Digitalis, Asteraceae (own observations on Centaurea and Artemisia in the Italian Valle di Susa) and Stachys recta.
Melitaea didyma inhabits nutrient-poor grasslands, rocky slopes, hot and meagre embankments and especially xerothermic calcareous grasslands from the lowlands up to 2000m above sea level (but lacks mostly in the northern Alps).
Melitaea didyma flies in in Central Europe in a single generation between late June and early August. In the south (e.g. Provence) in some lower regions there will be added a second generation (adults in May/June and August/September).
Fully-grown caterpillars are found in the case of a single generation in May/June. In the Swabian Alb, I found it on Plantago, Veronica, Verbascum and Stachys recta. In the south, they can be already found in April. The larvae seem to follow different strategies: some are mature quite early, others start feeding after hibernation not until early May (observations in the Valle di Susa).
Melitaea didyma is in strong decline north of the Alps, since it depends on xerothermic grasslands. The butterfly has a large population dynamics and is very sensitive to isolation. Melitaea didyma is still common as long as there is enough habitat in a dense network available as in the Southern Alps, some inner-alpine dry valleys or in Northern Greece.
The distribution covers North Africa, south and Central Europe and temperate Asia to Western China.