- Subfamily: Coliadinae - Gonepterygini
- Wingspan: 50-65 mm
- Flight period: Gen - Dec
- Spread: Common
- Host plants: Rhamnaceae
The Gonepteryx rhamni also known as Brimstone is a medium/large butterfly of the Pieridae family with a wingspan of 50-65 mm.
It is distributed throughout Europe (also present in North Africa, Asia up to the Far East), in Italy it is also present in the Islands. *
The dimorphism is quite evident, the male has sulfur yellow wings, especially the upper side, while the female has a white color with greenish reflections and they both have an orange dot in the center of each wing. In females, the underside of the wings tends to a cabbage green color with a brown / orange dot in the center of each wing, in the males the lower pages are lemon yellow always with a brown / orange point.**
The shape and appearance of the wings are very similar to a leaf, very useful from the mimetic point of view.
Gonepteryx rhamni is one of the longest-living butterflies, up to thirteen months, although most of this time is spent in some sort of hibernation. It is often the first butterfly that can be encountered in spring, even in late January or February if there are particularly sunny and hot days. Univoltine butterfly, the eggs are laid singly on the leaves of Rhamnus cathartica (Spino cervino) or Rhamnus frangula (Buckthorn).
The larvae and pupae are both green in color and very well camouflaged which makes them difficult to find in nature. After the emergence from the pupal stage, the adult switches to the summer nectar diet in order to create energy reserves for the winter. At the end of August they begin their long sleep.
The larvae feed solely on Rhamnaceae, in particular Rhamnus cathartica (The Common buckthorn) or Rhamnus frangula (Buckthorn).
* Lepidoptera mundi https://lepidoptera.eu/ - Fauna Europea https://fauna-eu.org/
** Bestimmungshilfe für die in Europa nachgewiesenen Schmetterlingsarten - http://lepiforum.de/