Coleoptera - Beetles

Rutpela (Strangalia) maculata (Poda, 1761): one of the most common coleopters in Alpago, frequently found on Umbelliferous plants. (Photo E.Gatti)

     In the display case for Carabid Coleopters there is a pair (male and female)and the larva of Carabus (Procerus) gigas Creutzer, 1799: this is a species with a very wrinkled, black, upper tegument, whereas its larva is black with a fine shade of blue. This is the biggest Carabid in Italian fauna, reaching 6.5 cm in length. In Italy it is mainly found in Friuli Venezia Giulia and the Belluno area, and it is particularly frequent in all parts of Alpago. The C. gigas seems to be able to form hybrids with the similar Carabus (Procustes) coriaceus Linne, 1758, (see show case), something rare among coleopters.
     In the adjacent show case, among other species is the Pterostichus (Oreophilus) multipunctatus Dejean 1828. It is interesting for its present day distribution, relic of a period when, before the Quaternary era, it once occupied a much larger area; now, however, besides living in the west-central Alps, it is found in two local areas, Mount Grappa and Mount Cavallo. Here the P. multipunctatus was saved from destruction by the quaternary glaciers because these two mountainous areas stuck out above the ice and acted as a refuge.
     In another show case of Coleopters we can see the conspicuous Lucanus cervus (Linne, 1758), more commonly known as the “Stag beetle”.
     This name comes from the male’s elongated jaws which look like a stag’s antlers: it is the biggest European coleopter, reaching 8.5 cm in length.
Its larva thrives in the dying, rotting wood of oak trees. The past habit of taking old, unhealthy wood out of the forest led to the habitat of this species becoming rare and, consequently, the species itself.
     Another show case contains further Coleopters of a certain importance: Donacia (Fabricus, 1775) and Plateumaris (Thomson, 1859). The ecological impotance of the Donacia comes from their being associated with wetlands (marsh reedbeds and water lilies) found in Alpine pools, ponds and dead-end river beds.
     These environments are disappearing as the wetlands are reclaimed and Alpine pastures are abandoned. Thus plant and animal species of these habitats are facing extinction
     Three species of Donacia have been found in Alpago:
- Donacia reticolata (Gyllenhal, 1817), found in the “Lamaraz” (wetland) at S. Anna near Tambre at 1,050 metres altitude and in the wetland alongside the Lake of Santa Croce near Farra d’Alpago at the altitude of 370 metres. It is found on the following plants: Sparganium, Carex and Typha latifoglia; we have also found it on Phragmites australis.
- Donacia acquatica (Linne, 1758) found in the “Lamaraz” at S.Anna at 1,050 metres above sea level. It feeds on Sparganium simplex, Ranunculus and Carex.
Plateumaris consimilis (Schrank, 1781) found in various parts of Alpago: Tambre at 920 metres, Lamaraz at S. Anna at 950 metres, Pianon (Tambre) at 950 metres, Casera Cate (Chies d’Alpago) at 1,050 metres, Pian Formosa (Chies d’Alpago) at 1,100 metres and S. Daniele (Chies d’Alpago) at 720 metres, Lake of Santa Croce wetland (Farra d’Alpago) at 270 metres.
Its colouring is variable, from metallic green to bronze, blue and sometimes deep red. It feeds on the pollen of different Carex plants and probably also on Caltha palustris.

     Coleopters can be distinguished from other groups of insects by their stiff wing-cases that cover the abdomen, and wings which open sideways when the insect takes flight, allowing the wings to stretch out.
Their insect order has the largest number of species in the world – about 400,000 of the insect species described to date are coleopters.