The heath fritillary (Melitaea athalia) is a medium sized butterfly, can reach a wingspan of 44-50 mm. It is easily confused with the congenera Melitaea nevadensis (Oberthür, 1904).
Melitaea athalia and Melitaea nevadensis, are genetically and morphologically distinct at the genital level.
The Melitaea athalia in Italy is located only in the extreme north east (Trentino, Veneto and Friuli) nevadensis in the rest of the peninsula, although some hybridization bands are known.
It has a strong variability in appearance that makes it difficult to identify.
Most of the specimens have the back of the orange wings, intersected by lines, lunules, and dark brown designs. The margin of the wings is white with brown chess.
The bottom of the rear wings features concentric white-cream and orange bands, including the central light band being the most lively and vivid.
One of the signs useful to distinguish this species is the double black line running along the edge of the rear wing, which in conjunction with the curved shape
of the fore wing margin, and the geographical position give it a good margin of certainty for its identification.
It frequents different habitats, from dry meadows to damp meadows, mountain and plain clearings, tree-lined areas, from basal plans to alpine areas.
With one or two generations, depending on latitude, there is a large number of eggs.Adults live in concentrated colonies, which allows a large number of specimens to be found in little areas.
They are visible from May to September.
Eggs are laid on host plants but sometimes on nearby plants. They open after about three weeks. The caterpillars are all together in a small silk nest that they abandon
after about 15 days to disperse and finish growth. Overwinter at larva stadium.
The adult caterpillar of two and a half centimeters length is black with orange yellow tubercles arranged on several parallel rows and covered with black hair.
There are a lots of host plants, mainly Melampyrum and Plantago, but also Veronica, Digitalis, Linaria and Achillea. The presence of the caterpillar was also recorded on other plants.