Glowworm or glow-worm is the common name for various groups of insect
larva
A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...
e and adult
larviform female
Larviform female is a biological phenomenon occurring in some insect species, where the females in the adult stage of metamorphosis resemble the larvae to various degrees, while the male appears more morphologically adult (as imagoes). The resembl ...
s that glow through
bioluminescence
Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorgani ...
. They include the European
common glow-worm and other members of the
Lampyridae
The Lampyridae are a family of elateroid beetles with more than 2,000 described species, many of which are light-emitting. They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production ...
, but bioluminescence also occurs in the families
Elateridae
Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, sp ...
,
Phengodidae and
Rhagophthalmidae among
beetle
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
s; as well as members of the genera ''
Arachnocampa
''Arachnocampa'' is a genus of nine fungus gnat species which have a bioluminescent larval stage, akin to the larval stage of glowworm beetles. The species of ''Arachnocampa'' are endemic to Australia and New Zealand, dwelling in caves and grotto ...
'', ''
Keroplatus'' and ''
Orfelia'' among
keroplatid fungus gnat
Fungus gnats are small, dark, short-lived gnats, of the families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae (order Diptera); they comprise six of the seven families placed in the superfamily Sc ...
s.
Beetles
Four families of beetles are
bioluminescent
Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some fungi, microorganisms inc ...
. The wingless
larviform female
Larviform female is a biological phenomenon occurring in some insect species, where the females in the adult stage of metamorphosis resemble the larvae to various degrees, while the male appears more morphologically adult (as imagoes). The resembl ...
s and larvae of these bioluminescent species are usually known as "glowworms". Winged males may or may not also exhibit bioluminescence. Their light may be emitted as flashes or as a constant glow, and usually range in colour from green, yellow, to orange.
The families are closely related, and are all members of the beetle superfamily,
Elateroidea
The Elateroidea are a large superfamily of beetles. It contains the familiar click beetles, fireflies, and soldier beetles and their relatives. It consists of about 25,000 species.
Description
Elateroidea is a morphologically diverse group ...
. Phylogenetic analyses have indicated that bioluminescence may have a single evolutionary origin among the families Lampyridae, Phengodidae, and Rhagophthalmidae; but is likely to have arisen independently among Elateridae.
* Family
Elateridae
Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, sp ...
– The click beetles. Of the estimated 10,000 species classified under this family, around 200 species from tropical regions of the Americas and some
Melanesia
Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from New Guinea in the west to the Fiji Islands in the east, and includes the Arafura Sea.
The region includes the four independent countries of Fiji, Vanu ...
n islands are bioluminescent. All of them are members of the subfamily Pyrophorinae, except for one species, ''
Campyloxenus pyrothorax'', which belongs to subfamily Campyloxeninae, and ''
Balgus schnusei
''Balgus'' is a genus of Central American click beetle (family Elateridae). They are one of several genera in the family which contain at least one bioluminescent species. The genus was originally placed in the family Eucnemidae, later transferre ...
'', in
Thylacosterninae
Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family (biology), family of beetles. Other names include elaters, sna ...
.
* Family
Lampyridae
The Lampyridae are a family of elateroid beetles with more than 2,000 described species, many of which are light-emitting. They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production ...
– True fireflies. Contains around 2,000 species found throughout the world. Some "glow worms" are in this family.
* Family
Phengodidae – Usually known as glowworm beetles. Contains around 230 species
endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to the
New World
The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...
. This family also includes
railroad worm
A railroad worm is a larva or larviform female adult of a beetle of the genus ''Phrixothrix'' in the family Phengodidae, characterized by the possession of two different colors of bioluminescence. It has the appearance of a caterpillar
...
s, which are unique among all terrestrial bioluminescent organisms in producing red light.
* Family
Rhagophthalmidae – Contains around 30 species found in
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
. The validity of this family has not been fully resolved. Rhagophthalmidae was formerly considered to be a subfamily under Phengodidae before being treated as a distinct family. Some authors now believe that it should be classified under Lampyridae.
Fungus gnats
Three genera of
fungus gnat
Fungus gnats are small, dark, short-lived gnats, of the families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae (order Diptera); they comprise six of the seven families placed in the superfamily Sc ...
s are bioluminescent, and known as "glowworms" in their larval stage. They produce a blue-green light.
The larvae spin sticky webs to catch food. They are found in caves, overhangs, rock cavities, and other sheltered, wet areas. They are usually classified under the family
Keroplatidae
Keroplatidae is a family of small flies known as fungus gnats. About 950 species are described, but the true number of species is undoubtedly much higher. The long-beaked fungus gnats, formerly placed in a separate family Lygistorrhinidae, hav ...
, but this is not universally accepted and some authors place them under
Mycetophilidae
Mycetophilidae is a family of small flies, forming the bulk of those species known as fungus gnats. About 3000 described species are placed in 150 genera, but the true number of species is undoubtedly much higher. They are generally found in the ...
instead. Despite the similarities in function and appearance, the bioluminescent systems of the three genera are not
homologous and are believed to have evolved separately.
* Genus ''
Arachnocampa
''Arachnocampa'' is a genus of nine fungus gnat species which have a bioluminescent larval stage, akin to the larval stage of glowworm beetles. The species of ''Arachnocampa'' are endemic to Australia and New Zealand, dwelling in caves and grotto ...
'' – around five species found only in
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
and
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
. The best-known member of the genus is the New Zealand glowworm, ''
Arachnocampa luminosa
''Arachnocampa luminosa'' (Skuse, 1891), commonly known as New Zealand glowworm or simply glowworm, is a species of fungus gnat solely endemic to New Zealand. The larval stage and the imago produce a blue-green bioluminescence. The species is kno ...
.'' The larvae are predatory and use their lights to lure prey into their webs.
* Genus ''
Orfelia'' – sometimes known as "dismalites". Contains a single species, ''
Orfelia fultoni'', found only in
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. Like ''Arachnocampa'' spp., their larvae may use their lights to attract prey like springtails and other small insects, but their main food is fungal spores.
* Genus ''
Keroplatus'' – found in
Eurasia
Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...
. Unlike ''Arachnocampa'' and ''Orfelia'', the larvae of ''Keroplatus'' feed only on fungal spores.
Their bioluminescence is believed to have no function and is
vestigial
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...
.
See also
*
Larviform
References
External links
{{wikiquote, Glowworms
Springbrook Glow Worms Research Centre.All about glow worms
rachnocampa flavain the Gold Coast hinterland, Queensland Australia.
All About Glow Worm in Tamborine, Gold Coast Descriptive information on Glow Worm Life Cycle and Where are found in Australia.
The UK Glow Worm Surveyhas county-by-county lists of glowworm sites in the UK.
Fly biology
Beetles by adaptation
Bioluminescent insects
Insect common names