A large white butterfly gliding slowly over a sunny slope, its wings marked with red spots: Parnassius apollo, the Apollo butterfly, is one of the most beautiful encounters you can have in the mountains. It is also a delicate, protected species, declining across much of Europe.
I photographed this butterfly at the top of Monte Grappa on a beautiful day, and had a speck and alpine cheese sandwich for lunch. A butterfly like that and a lunch like that: it’s hard to ask for more!
How to identify the Apollo butterfly
It belongs to the Papilionidae family, the same as the swallowtails, but unlike them it has no “tails” on its hindwings. It is large for a European butterfly: the wingspan is about 6-9 cm, and the female is generally larger than the male. The wings are white, with black spots on the forewings and the characteristic black-edged red spots on the hindwings. The pattern varies greatly from one individual to another and from one population to another.
Its flight also helps to identify it: slow and heavy, often broken up by stops on flowers.
Similar species
Two other species of the same genus live in our mountains. Parnassius mnemosyne is almost entirely white with a few black spots and lacks the Apollo’s red, while Parnassius phoebus, the small Apollo, is more closely tied to high altitudes.
Where Parnassius apollo lives in Italy
It favours open, sunny habitats at medium and high altitudes, with meadows, stony slopes and exposed rock. In Italy it is found between about 400 and 2,500 metres, but it is much more frequent above 1,000. It is fairly common in the Alps, while in the Apennines its presence is patchier, with isolated populations. It also lives in places that are surprising for a mountain butterfly, such as Aspromonte and the mountains of Sicily.
The best time to see it is generally from June to August, with differences depending on the altitude and climate of each area. There is only one generation a year.
What it eats: from Sedum to mountain flowers
The caterpillar is very selective: it feeds almost exclusively on succulents of the Crassulaceae family, especially the genus Sedum, such as Sedum album and Sedum telephium, and sometimes on Sempervivum. This is why the butterfly’s presence depends closely on that of its host plant.
The adult, on the other hand, feeds on the nectar of various flowers. In a study in Aspromonte it mainly visited Asteraceae and Campanulaceae, the same flowers frequented by bees and other butterflies.
The life cycle of the Apollo butterfly
During mating, the male leaves a secretion on the female’s abdomen that hardens, called a sphragis, which prevents her from mating again. The female then lays her eggs one at a time, on the host plant or on other nearby surfaces.
Winter is spent in the egg, with the small caterpillar already formed inside, which emerges at the start of spring. The caterpillar is black with conspicuous orange spots and feeds for about 10 weeks. Like other Papilionidae, if disturbed it can extend an organ behind its head, the osmeterium, which gives off an unpleasant smell. The chrysalis stage lasts about two or three weeks, and the adult butterfly in turn lives for only 2-3 weeks. The whole cycle takes a year, even though the butterfly is only seen in flight for a few months.
Why is Parnassius apollo protected?
It is one of the most threatened European butterflies: according to one estimate, it has declined by 20-50% over the last 25 years. It is listed in Annex IV of the Habitats Directive, Appendix II of CITES and Appendix II of the Bern Convention, so it must not be caught or collected.
The main threat is the change to its habitat. When traditional grazing is abandoned, shrubs and woodland close over the meadows and Sedum disappears. Global warming also weighs on a species tied to cold winters and sunny summers. In the past, in some areas, collecting has also played a part.
Protecting it means protecting much more. The Apollo is considered an “umbrella species”: safeguarding its habitats also protects many lesser-known species that live in the same places.
Why is it called that?
The scientific name recalls Greek myth: Parnassus is the mountain dedicated to the god Apollo, considered the sacred home of poets. A fitting name for such an elegant butterfly that lives in the mountains.
If you come across one, enjoy the show: watch and photograph it calmly, without catching it and without trampling the plants around it. You can find other small inhabitants of the natural world in my gallery dedicated to insects and in the macro world.
