Photo 1. A Charissa moth, photographed in autumn 2016. The patterns and colours of its wings are perfectly adapted to the limestone rock surface on which it rests.  (Photo by Patrik Krstinić)

A GEOMETER MOTH ON THE ROCKY SHORE OF PRVIĆ ISLAND

The coastal limestone cliffs of Prvić Island are characterized by a rolling micro-relief, a diversity of colours and a biological “diversity” of coatings of microorganisms. Some of the smaller recesses caused by the erosion of limestone have taken on a grey colour, probably because of the biofilms of microorganisms that make up the epilithic and endolithic coatings on the rocks. The protruding parts of the rocks, in between these recesses, are of a contrasting, lighter colour and seem to have no dense overgrowth of microorganisms. A geometer moth, probably of the genus Charissa, either unintentionally or not, has perfectly adapted the colours of its body to the colour of the surface against which its wings are pressed, as it rests during the day in this habitat. Grey spots and lighter, ochre spots alternate on its wings imitating the alternating greyish recesses and lighter protrusions of the limestone rock.

Marko Randić

Photo 2. The rock habitat in which the Charissa moth was found. (Photo by Patrik Krstinić)