Common Glow-worm Larva / Larva krijesnice

Description:

These are beetles, as evidenced by the hard cases which close over the wings when they are not in use. Lampyris noctiluca presents a conspicuous sexual dimorphism. The males are winged, with brown elytra, a clearer pronotum and a large brown spot in the middle, while females are larviforme, wings are missing and they are often twice the size of the males (up to 25 mm in length). These beetles use their bioluminescence to attract mates. The adult females are mostly famed for their glow, although all stages of their life cycle are capable of glowing. The flightless larviform females sit in grass and low vegetation at dusk (typically 22 - 23 h, although in shaded places such as woods it will be earlier), turning their rear-ends upwards. Greater chances of mating success result if they find an open area to display in where the light is more visible to males. They emit yellowish-green light from the translucent underside of their last three abdominal segments to attract the smaller males, which are winged. They will glow for 2 hours and then retreat back into their hiding place until the next night, or stop glowing as soon as they find a mate. The females can survive up to 10 consecutive nights doing this. The light can be seen by males up to 50 yards away. The light is emitted continuously, although they will wave their abdomens from side to side, which gives the impression of it brightening and dimming. Larvae are sometimes seen to glow, although they seem able to turn off their light more easily than the female, especially when disturbed. The insect can regulate its light production by controlling the oxygen supply to the light emitting membranes containing luciferin. The chemical reaction producing the light from luciferin is catalysed by luciferase, the exact chemical structure of which is determined by the glow worms individual genetic structure, which in turn determines subtle differences in the light produced from individual to individual. Virtually all of the energy produced is light; only 2% is heat. The males are sometimes attracted to man-made light fixtures. The peak glowing period is evenings in June and July.

Habitat:

The range of this beetle stretches from Portugal and Britain in the west, right across Europe and Asia to China in the east. It also survives further north than any other firefly, almost reaching the Arctic Circle. It is not found in North or South America. hey are found in old-growth grassland, especially on chalk and limestone soils. They are also found in verges, hedgebanks, and on heaths. The larvae live in sheltered places – under rocks and wood, but do crawl over different terrains.