Carabid beetle  (Carabus olympiae)

Carabus olympiae is classified as Vulnerable (VU) on the IUCN Red List (1).

A large, colourful beetle, Carabus olympiae is unusual in being endemic to just one small area of the Italian Alps (2). As in other ground beetles (Carabidae), the body is rather long and flattened, with a clearly differentiated head, thorax and abdomen, long, slender legs, and quite prominent mandibles and palps (3) (4).

Although not as spectacularly coloured as some of its relatives, Carabus olympiae is still an attractive insect, with a dark purplish-blue head and pronotum, the margins of which have a golden sheen, and brilliant, metallic, golden-green elytra, with coppery or purple margins (2).

Carabus olympiae is endemic to a small area of the upper Val Sessera, on the northern slope of the Moncerchio, in the Italian Alps (1) (2). Attempts to introduce the species to parts of the French Alps are thought to have been largely unsuccessful (2).

Believed to have originally been a forest-dweller, Carabus olympiae now occurs in more open habitats, ranging from beech forest to open shrubland, at elevations of around 800 to 2,000 metres (2). It may have a preference for beech forest as well as areas of alpen rose (Rhododendron ferrugineum) and bilberry (Vaccinium myrtillus) (2) (5) (6), but avoids pastures (5).

Most active at night (2) (5), particularly during periods of thunderstorms and high humidity (2), Carabus olympiae is a voracious predator. Both adults and larvae actively hunt for invertebrate prey, and are thought to have a preference for molluscs, in particular the snail Arianta arbustorum (2) (3) (4).

The main period of activity of Carabus olympiae runs from June to September (2), peaking in July (5), with the eggs laid in late spring or early summer. The number of eggs is relatively low, with each female laying a maximum of around 29. The larvae of Carabus olympiae pass through three developmental stages before pupating, with total development taking approximately one to one and a half months. The young adults emerge at the end of the summer and feed for about a month, building up fat reserves before entering diapause during the winter (2) (4). Eggs laid late in the year may pass the winter as larvae, and it is possible that some individuals of this species may delay reproduction if conditions are unfavourable, or even reproduce in more than one successive year (2).

Although the very restricted range of this species is believed to have resulted from natural processes occurring after the last ice age, its limited distribution makes Carabus olympiae particularly vulnerable to extinction. The population also fluctuates widely from year to year, and is generally much lower than in related, more widespread species (2).

The main threat to Carabus olympiae is tourist development, in particular for the skiing industry, with the construction of ski runs and pistes severely altering the habitat, and associated roads and traffic also causing damage (2) (5) (7). Potential plans for a hydroelectric dam and for the construction of an artificial lake to feed snow-cannons have also further threatened the area (2).

In addition, activities such as cattle grazing may alter the density of shrubs, potentially affecting Carabus olympiae (6), and the removal of old and dead trees as part of forest management may remove important habitat for the larvae of this and other beetle species (2).

Carabus olympiae is listed on Annex II of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) (8), and as a priority species on Annexes II and IV of the EC Habitats Directive (9). Although efforts have been made to extend the range of the species by introducing it to parts of the French Alps, these do not appear to have been successful (2).

Conservation measures needed for this rare and unique beetle include better protection for the sites where it occurs, and further surveys to determine whether small populations exist in any other areas (2). It will also be important to properly manage the habitat of Carabus olympiae, in particular by managing the availability of shrub cover, controlling grazing pressure, and developing more environmentally friendly ways of constructing ski pistes (5) (6) (7).

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about Carabus olympiae and other carabid beetles, see:

• Carabidae of the World:
  http://www.carabidae.ru/
• Council of Europe. (1996) Background Information on Invertebrates of the Habitats Directive and the Bern Convention. Part 1 - Crustacea, Coleoptera and Lepidoptera. Council of Europe Publishing, Strasbourg.