Big blue runner(Procerus scabrosus) [bg: golyam sin begach] is a shiny blue-violet beetle, the bottom side of it is black with metallic lustre. The elytra are lengthways rough, covered with granular structure. The coloration varies from blue to violet and sometimes can be green or almost black. This beetle is relatively large, with a length of 40-56 mm.
It can be found on the soil surface, often in the foliage, mostly in deciduous, but sometimes also in mixed forests as well as in gardens and parks. It runs quick, hence its name. But when disturbed the beetle splatters around acrid fluid coming out of its belly. Catching one of them, you must be careful not to get this liquid in the eyes, because it can cause blindness. The blue runner is a predator; it feasts on terrestrial molluscs, especially slugs, so if the year is rainy and the population of slugs increases proportionally increases the beetle population. The fed up beetles sometimes bury in the soil for several days.
The big blue runner breeds in the spring, usually in April. The newly hatched larva is white, but after 10-12 hours becomes violet-black colour. About 30-40 hours after hatching, the larva begins to feed on terrestrial molluscs, like the adult insect, and then turns to pupa in a special chamber deep down the soil. The imago is wintering (adult insects). Life expectancy of the imago is 2-3 years.
In Bulgaria the big blue runner is a [color=red]protected species, listed in the European Red book.[/color] It occurs in southern Bulgaria, Strandzha Mountain, Eastern Rhodopes and Stara Planina (Balkan Mountain).