How to recognise central European glow-worm species
Raphaël de Cock
Common European Glow-worm Central European Firefly Lesser Glow-worm
Lampyris noctiluca Lamprohiza splendidula Phosphaenus hemipterus
Figure 1. Three central European glow-worm species: males, females and ventral view on their light organ patterns (black coloured zones). Source: after Geisthardt 1971
Figure 2. Glow-worm larvae:
1. Lampyris noctiluca
2. Lamprohiza splendidula
3. Phosphaenus hemipterus
Lampyris noctiluca L.
Female: 15-20 (25?) mm, wingless, colour: brown segments connected with pinkish skin, light organs only in the last three body segments. See Figure 1 and the following links:
Male: 15 mm, winged, colour: brown, looks like other beetles, vague translucent windows in head shield, huge eyes, glows from pair of tiny (larval) light organs in the penultimate segment when disturbed but not at flight.
Larva: velvety jet-black with lateral yellow-pinkish dots on each segment corner, glows with slow pulses (about 10 seconds) when active at night and occasionally when disturbed.
Lamprohiza splendidula L.
Female: 10-15 mm, tiny reduced wing cases, colour: ivory yellow, bears more than 4 ventro- lateral light organs spread all over the abdomen that also shine dorsally through the body (usually a bright pair in the 2nd abdominal segment and another pair in the 6th segment with in between these two pair a variable amount of smaller lateral lights), and ventrally very bright adult lanterns at the end of the body.
Male: 10 mm, lookalike of male Lampyris noctiluca but smaller, clear transparent windows in head shield and 2 bright luminous bands in the last ventral segments, glows brightly at flight, hence its name “firefly”
Larva: dorsally brownish, ventrally yellowish, flattened, reminiscent in overall shape to woodlouse, broadened segments, several light organs that shine dorsally through the cuticle (usually a bright pair in the 2nd abdominal segment and another pair in the 6th segment with in between these two pairs a variable amount of smaller lateral lights), glows only when disturbed/stimulated (hard sounds or when touched)
Phosphaenus hemipterus Fourcroy
Female: 10mm, colour brown and pink (mini female Lampyris noctiluca), but lacks adult light organs, normally doesn’t glow spontaneously, only when disturbed from a ventral pair of light organs in the penultimate segment, lives hidden.
Male: 7-10mm, colour: black, pinkish skin & spot between head and legs, huge antennae, shortened wing cases, flightless, crawls by daylight between stones, over paths, bare patches and along walls.
Larva: brownish, ventrally pinkish, more slender than larval Lampyris noctiluca, a ventral pair of light organs in penultimate segment, glows when disturbed or in pulses (especially late in summer and in autumn).
See a picture of the larvae of the three species at http://bio-www.uia.ac.be/bio/deco/glmlarvn.jpg