- Subfamily: Melitaeinae - Melitaeini
- Wingspan: 40-50 mm
- Flight period: May - Sep
- Spread: Common
- Host plants: Orobanchaceae - Plantaginaceae - Scrophulariaceae
The Melitaea athalia also called Heath Fritillary is a common and widespread butterfly, of medium size, with a wingspan of 40 - 50 mm.
It is easily confused with the congener Melitaea nevadensis (Oberthür, 1904) or according to the new nomenclature Melitaea celadussa Fruhstorfer , 1910. *
Melitaea athalia and Melitaea nevadensis/celadussa are genetically and morphologically distinct at the genital level.
The Melitaea athalia in Italy is found only in the extreme north east (Trentino, Veneto and Friuli Venezia Giulia) the Melitaea nevadensis / celadussa in the rest of the peninsula,
even if some hybridization bands are known. ** At European level it is absent only from Ireland ****
Melitaea athalia has a marked variability in appearance which makes it difficult to identify.
Most of the specimens have the back of the wings of orange color, intersected by lines, lunulae and drawings of dark brown color. The edge of the wings is white with brown checks. The lower part of the hind wings has cream-white and orange concentric bands, among which the central clear band is the most lively and showy. One of the characters useful to distinguish this species is the double black line that runs along the margin of the rear wing, which, together with the curved shape of the edge of the front wing and the geographical position, give its identification a good margin of certainty.
Rather constant character is the brown color of the labial palps when seen from above. ***
It frequents different habitats from dry to wet meadows, mountain and plain clearings, wooded areas, from the basal to the alpine level. With one or two generations depending on the latitude, it lays a large number of eggs. The adults live in concentrated colonies which allows to find a large number of specimens in restricted areas. They are visible from May to late September.
The eggs are laid on host plants but sometimes also on nearby essences. They hatch after about three weeks. When they hatch, the caterpillars all remain together in a small silky nest which they abandon after about 15 days and then disperse and complete growth. It overwinters in the larva stage. The adult caterpillar, 25 mm long, is black with yellow-orange tubercles arranged in several parallel rows and covered with blackish hairs.
There are also several host plants, (Orobanchaceae - Plantaginaceae - Scrophulariaceae) mainly Melampyrum and Plantago but also Veronica, Digitalis, Linaria and Achillea. The presence of the caterpillar has also been recorded on other plants.
* An updated checklist of the European Butterflies (Lepidoptera, Papilionoidea)
** http://www.iucn.it/ - http://www.farfalleitalia.it/
*** P. Paolucci, Le farfalle dell’Italia nordorientale, Sommacampagna, Cierre, 2010, p.196