Corethrellidae are a family of biting

midges A midge is any small fly, including species in several families of non-mosquito nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midg ...

, small flying insects belonging to the order

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...

, females of which feed on the blood of

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

s. The members of the family are sometimes known as frog-biting midges. The family currently consists of just one

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

, totalling 115 extant and 10 fossil species worldwide. Most

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

species are found in the lower latitudes, usually associated around the

tropics The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

. They are tiny flies with a wing length of 0.6-2.5 mm. The

wing venation Insect wings are adult outgrowths of the insect exoskeleton that enable insect flight, insects to fly. They are found on the second and third Thorax (insect anatomy), thoracic segments (the mesothorax and metathorax), and the two pairs are often ...

is similar to

Culicidae Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

(R 4 branched, M 2 branched, Cu 2 branched) with branches of Rs and M nearly parallel. R1 is, however, closer to Sc or almost midway between Sc and R2. They were, from 1962 until 1989, placed as a tribe Corethrellini within the Chaoborinae, a subfamily of Culicidae. Adult female ''Corethrella'' are attracted to the mating calls of male

s, their chosen host taxa. As obligate external parasites, the midges feed almost exclusively on the blood of these frogs. Because of this, ''Corethrella'' follow typical distribution patterns of external parasites and are restricted to only areas with abundant populations of their host frogs. Female midges most likely detect their hosts using a specialized organ called a

Johnston's organ Johnston's organ is a collection of sensory cells found in the pedicel (the second segment) of the antennae in the class Insecta. Johnston's organ detects motion in the flagellum (third and typically final antennal segment). It consists of sc ...

, a collection of sensory cells found on the second antenna segment. There is evidence of host specificity and selection of particular biting sites for some species. ''Corethrella'' species have been observed sucking blood from individuals of the tree frog genus ''

Hyla ''Hyla'' is a genus of frogs in the tree frog family Hylidae. As traditionally defined, it was a wastebasket genus with more than 300 species found in Europe, Asia, Africa, and across the Americas. After a major revision of the family, most of t ...

''. Specifically, the North American tree frog species '' Hyla avivoca'', '' Hyla cinerea'' and '' Hyla gratiosa'' were recorded as confirmed corethrellid hosts in a 1977 study. A few, select species are known

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

s of frog-specific species of the parasitic protozoan ''

Trypanosoma ''Trypanosoma'' is a genus of kinetoplastids (class Trypanosomatidae), a monophyletic group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Euglenozoa. The name is derived from the Ancient Greek ''trypano-'' (b ...

''. Corethrellid parasitism is thus a recorded cause of

trypanosomiasis Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus ''Trypanosoma''. In humans this includes African trypanosomiasis and Chagas disease. A number of other disea ...

among host frog populations. The family contains members that date to the lower

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Period some 110 million years ago. At least one species, ''

Corethrella andersoni ''Corethrella'' is a genus of midges that are classified in the family (biology), family Corethrellidae. Systematics The genus currently comprises 125 extant and 10 fossil species. Extant species Subgenus ''Corethrella'' Coquillett, 1902 # ...

'', has been found in Burmese

amber Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia ...

deposits dating from this time.

References

Bibliography

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External links

Corethrellidae Corethrellidae are a family of biting midges, small flying insects belonging to the order Diptera, females of which feed on the blood of frogs. The members of the family are sometimes known as frog-biting midges. The family currently consists of ...

in Italian {{Taxonbar, from=Q1627654 Nematocera families Culicoidea Monogeneric Diptera families