Lampyris noctiluca
Encyclopedia
Lampyris noctiluca, the common glow-worm of Europe
(see also "glowworm
"), is a firefly
species
of the genus
Lampyris
. 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 millimetre or 0.984251968503937 in 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.
In Britain, this species is fairly common compared to its cousin Phosphaenus hemipterus – the lesser glow worm – which is very rare.
. It is not found in North or South America.
The flightless larviform female
s sit in grass and low vegetation at dusk (typically 22h00 to 23h00, 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.
s. 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.
Typically 50–100 are laid over 3 days, the adult not surviving to see them hatch. They are laid in fairly moist places, e.g. stem of grass or under moss.
The eggs are pale yellow, 1 mm across. They may glow faintly yellow and take between 27 and 45 days to hatch depending on the weather (colder=longer).
The eggs hatch after 2 or 3 weeks. Larvae and adult females look similar, however larvae have light spots on each of 12 segments, whereas adult females have a completely black back.
The predatory larva
e feed for two or three years on slugs and snail
s which they inject with a brown toxic digestive fluid, delivered by a series of nips and bites. The poison takes a while to work, and the larva has to be careful not to become stuck to any protective mucus that its prey may secrete. The prey is gradually paralysed and the digestive fluid turns part of it into a brown broth that the larva can lap up. The prey remains alive, and some partially eaten victims have been known to crawl away after the meal.
The slugs and snails are often 200 times the weight of the beetle larva. The larvae are nocturnal, and are most active during moist conditions, when their prey are most active.
The larvae may moult four to five times in their lifetime. They spend their winter under logs, stones, wood holes or leaf litter, their bodies drawn in like concertinas, hibernating as their food source becomes increasingly hard to find. They wake up in spring, and the cycle is repeated for one more year.
They become adults from May to July, eating little, surviving on food reserves built up during its time as a larva, and dying after reproducing.
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(see also "glowworm
Glowworm
Glowworm, or glow worm, is the common name for various groups of insect larvae and adult larviform females that glow through bioluminescence. They may sometimes resemble worms, but all are insects .-Classification:Major families are:* Lampyridae , found around the world...
"), is a firefly
Firefly
Lampyridae is a family of insects in the beetle order Coleoptera. They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuous crepuscular use of bioluminescence to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Lampyris
Lampyris
Lampyris is a genus of beetle in the firefly family . In most of western Eurasia, they are the predominant fireflies. They produce a continuous glow.; the larvae and larviform females are among those organisms commonly called "glowworms"....
. 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 millimetre or 0.984251968503937 in in length).
These beetles use their bioluminescence
Bioluminescence
Bioluminescence is the production and emission of light by a living organism. Its name is a hybrid word, originating from the Greek bios for "living" and the Latin lumen "light". Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in...
to attract mates. The adult females are mostly famed for their glow, although all stages of their life cycle are capable of glowing.
In Britain, this species is fairly common compared to its cousin Phosphaenus hemipterus – the lesser glow worm – which is very rare.
Distribution
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 CircleArctic Circle
The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. For Epoch 2011, it is the parallel of latitude that runs north of the Equator....
. It is not found in North or South America.
The glow
Larviform female
Larviform female is biological phenomenon occurring in some species, where the females in the adult stage of metamorphosis resemble the larvae to various degrees. Typically, the female is wingless and generally larger than the male...
s sit in grass and low vegetation at dusk (typically 22h00 to 23h00, 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
Luciferin
Luciferins are a class of light-emitting biological pigments found in organisms that cause bioluminescence...
. The chemical reaction producing the light from luciferin is catalysed by luciferase
Luciferase
Luciferase is a generic term for the class of oxidative enzymes used in bioluminescence and is distinct from a photoprotein. One famous example is the firefly luciferase from the firefly Photinus pyralis. "Firefly luciferase" as a laboratory reagent usually refers to P...
, 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
They are found in old-growth grassland, especially on chalk and limestone soilSoil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s. 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.
Life cycle
Once the females have attracted the males with their glow, they mate, lay eggs, and die.Typically 50–100 are laid over 3 days, the adult not surviving to see them hatch. They are laid in fairly moist places, e.g. stem of grass or under moss.
The eggs are pale yellow, 1 mm across. They may glow faintly yellow and take between 27 and 45 days to hatch depending on the weather (colder=longer).
The eggs hatch after 2 or 3 weeks. Larvae and adult females look similar, however larvae have light spots on each of 12 segments, whereas adult females have a completely black back.
The predatory larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e feed for two or three years on slugs and snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s which they inject with a brown toxic digestive fluid, delivered by a series of nips and bites. The poison takes a while to work, and the larva has to be careful not to become stuck to any protective mucus that its prey may secrete. The prey is gradually paralysed and the digestive fluid turns part of it into a brown broth that the larva can lap up. The prey remains alive, and some partially eaten victims have been known to crawl away after the meal.
The slugs and snails are often 200 times the weight of the beetle larva. The larvae are nocturnal, and are most active during moist conditions, when their prey are most active.
The larvae may moult four to five times in their lifetime. They spend their winter under logs, stones, wood holes or leaf litter, their bodies drawn in like concertinas, hibernating as their food source becomes increasingly hard to find. They wake up in spring, and the cycle is repeated for one more year.
They become adults from May to July, eating little, surviving on food reserves built up during its time as a larva, and dying after reproducing.
Threats to species numbers
Threats include habitat destruction, habitat fragmentation, pollution, distraction from artificial lights, insufficient grazing and climate change.External links
- Identification of European Glowworms
- Kendall Bioresearch
- The UK Glow Worm survey home page contains a wealth of information on this species
- UK Distribution
- Biological Records Centre
- Glow worms book by John Tyler
- Biolib
- Fauna Europaea
