Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006

Ssp. genava, Switzerland, July 2006



Distribution

There remains considerable debate over the taxonomy of this species. To start with, there is ongoing dispute about whether it should be hermione or alcyone, and although hermione is currently the official name, some are petitioning the ICZN to rule for alcyone. On top of this, the status of the subspecies genava, from Switzerland and North Italy, is uncertain. Some insist it is a good species - and it is morphologically distinct in the number of Jullien organs - while orthodoxy seems to prefer subspecific rank. Most of the pictures above are of this subspecies/species, with just the three from Spain belonging to subspecies vandalusica.

This is a typical grayling, with all the grayling habits. It has a powerful, rather bouncing or swooping flight, often terminating in an abrupt landing on the ground, when it adjusts itself to minimise shadow, drops the forewing and believes it can't be seen. This is often true (that it can't be seen), though it is less brilliantly camouflaged than the grayling and seems less choosy about the substrate it lands on. It frequently lands on tree trunks too, and is certainly not exclusively attracted to rocky terrain, but I think I see it more on rocks than I do the woodland grayling.

Separating this species from the woodland grayling, with which it flies in some locations, is not easy. It is smaller - always less than 33mm from body to wingtip - but this is not always easy to judge in the field. The white, discal band on the underside hindwing is typically narrower and better defined outwardly - the outer contour more or less following the line of the inner. This also is a somewhat variable feature. As a rule, the apical eyespot on the underside forewing is neatly outlined in buff, with a defined, dark 'eyebrow' above. The eyebrow of woodland grayling is usually less neat and defined. None of these features - apart from the size - is really constant or diagnostic and the official line is that definitive identification is impossible without dissection or examination in vivo of the Jullien organs.

The rock grayling flies in a single brood from June to October. It feeds on various grasses, including Brachypodium species and sheeps' fescue, and hibernates as a caterpillar.