The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many species superficially resemble mosquitoes, but they lack the wing scales and elongated mouthparts of the Culicidae.
The name Chironomidae stems from the Ancient Greek word kheironómos, "a pantomimist".
|Male Chironomus plumosus|
This is a large taxon of insects; some estimates of the species numbers suggest well over 10000 world-wide. Males are easily recognized by their plumose antennae. Adults are known by a variety of vague and inconsistent common names, largely by confusion with other insects. For example, chironomids are known as "lake flies" in parts of Canada and Lake Winnebago, Wisconsin, but "bay flies" in the areas near the bay of Green Bay, Wisconsin. They are called "sand flies", "muckleheads", "muffleheads", "Canadian soldiers", or "American soldiers" in various regions of the Great Lakes area. They have been called "blind mosquitoes" or "chizzywinks" in Florida. However, they are not mosquitoes of any sort, and the term "sandflies" generally refers to various species of biting flies unrelated to the Chironomidae.
The biodiversity of the Chironomidae often goes unnoticed because they are notoriously difficult to identify and ecologists usually record them by species groups. Each morphologically distinct group comprises a number of morphologically identical (sibling) species that can only be identified by rearing adult males or by cytogenetic analysis of the polytene chromosomes. Polytene chromosomes were originally observed in the larval salivary glands of Chironomus midges by Balbiani in 1881. They form through repeated rounds of DNA replication without cell division, resulting in characteristic light and dark banding patterns which can be used to identify inversions and deletions which allow species identification.
Larval stages of the Chironomidae can be found in almost any aquatic or semiaquatic habitat, including treeholes, bromeliads, rotting vegetation, soil, and in sewage and artificial containers. They form an important fraction of the macrozoobenthos of most freshwater ecosystems. They are often associated with degraded or low-biodiversity ecosystems because some species have adapted to virtually anoxic conditions and are dominant in polluted waters. Larvae of some species are bright red in color due to a hemoglobin analog; these are often known as "bloodworms". Their ability to capture oxygen is further increased by their making undulating movements.
Many reference sources in the past century or so have repeated the assertion that the Chironomidae do not feed as adults, but an increasing body of evidence contradicts this view. Adults of many species do, in fact, feed. The natural foods reported include fresh fly droppings, nectar, pollen, honeydew, and various sugar-rich materials.
The question whether feeding is of practical importance has by now been clearly settled for some Chironomus species, at least; specimens that had fed on sucrose flew far longer than starved specimens, and starved females longer than starved males, which suggested they had eclosed with larger reserves of energy than the males. Some authors suggest the females and males apply the resources obtained in feeding differently. Males expend the extra energy on flight, while females use their food resources to achieve longer lifespans. The respective strategies should be compatible with maximal probability of successful mating and reproduction in those species that do not mate immediately after eclosion, and in particular in species that have more than one egg mass maturing, the less developed masses being oviposited after a delay. Such variables also would be relevant to species that exploit wind for dispersal, laying eggs at intervals. Chironomids that feed on nectar or pollen may well be of importance as pollinators, but current evidence on such points is largely anecdotal. However, the content of protein and other nutrients in pollen, in comparison to nectar, might well contribute to the females' reproductive capacities.
Adults can be pests when they emerge in large numbers to even cause difficulty during driving as they can opaque the wind screen. They can damage paint, brick, and other surfaces with their droppings. When large numbers of adults die, they can build up into malodorous piles. They can provoke allergic reactions in sensitive individuals.
Larvae and pupae are important food items for fish, such as trout, banded killifish, and sticklebacks, and for many other aquatic organisms as well such as newts. Many aquatic insects, such as various predatory hemipterans in the families Nepidae, Notonectidae, and Corixidae eat Chironomidae in their aquatic phases. So do predatory water beetles in families such as the Dytiscidae and Hydrophilidae. The flying midges are eaten by fish and insectivorous birds, such as swallows and martins. They also are preyed on by bats and flying predatory insects, such as Odonata and dance flies.
The Chironomidae are important as indicator organisms, i.e., the presence, absence, or quantities of various species in a body of water can indicate whether pollutants are present. Also, their fossils are widely used by palaeolimnologists as indicators of past environmental changes, including past climatic variability. Contemporary specimens are used by forensic entomologists as medico-legal markers for the postmortem interval assessment.
A number of chironomid species inhabit marine habitats. Midges of the genus Clunio are found in the intertidal zone, where they have adjusted their entire life cycle to the rhythm of the tides. This made the species Clunio marinus an important model species for research in the field of chronobiology.
Anhydrobiosis is the ability of an organism to survive in the dry state. Anhydrobiotic larvae of the African chironomid Polypedilum vanderplanki can withstand prolonged complete desiccation (reviewed by Cornette and Kikawada). These larvae can also withstand other external stresses including ionizing radiation. The effects of anhydrobiosis, gamma ray and heavy-ion irradiation on the nuclear DNA and gene expression of these larvae were studied by Gusev et al. They found that larval DNA becomes severely fragmented both upon anhydrobiosis and irradiation, and that these breaks are later repaired during rehydration or upon recovery from irradiation. An analysis of gene expression and antioxidant activity suggested the importance of removal of reactive oxygen species as well as the removal of DNA damages by repair enzymes. Expression of genes encoding DNA repair enzymes increased upon entering anhydrobiosis or upon exposure to radiation, and these increases indicated that when DNA damages occurred, they were subsequently repaired. In particular, expression of the Rad51 gene was substantially up-regulated following irradiation and during rehydration. The Rad51 protein plays a key role in homologous recombination, a process required for the accurate repair of DNA double-strand breaks.
The family is divided into 11 subfamilies: Aphroteniinae, Buchonomyiinae, Chilenomyinae, Chironominae, Diamesinae, Orthocladiinae, Podonominae, Prodiamesinae, Tanypodinae, Telmatogetoninae, and Usambaromyiinae. Most species belong to Chironominae, Orthocladiinae, and Tanypodinae. Diamesinae, Podonominae, Prodiamesinae, and Telmatogetoninae are medium-sized subfamilies with tens to hundreds of species. The remaining four subfamilies have fewer than five species each.
Ablabesmyia is a genus of non-biting midges in the subfamily Tanypodinae of the bloodworm family Chironomidae.Belgica antarctica
Belgica antarctica, the Antarctic midge, is a species of flightless midge, endemic to the continent of Antarctica. At 2–6 mm (0.079–0.24 in) long, it is the largest purely terrestrial animal native to the continent, as well as its only insect.
It also has the smallest known insect genome as of 2014, with only 99 million base pairs of nucleotides (and about 13,500 genes).Chaoboridae
The Chaoboridae, commonly known as phantom midges or glassworms, are a family of fairly common midges with a cosmopolitan distribution. They are closely related to the Corethrellidae and Chironomidae; the adults are differentiated through peculiarities in wing venation.
If they eat at all, the adults feed on nectar. The larvae are aquatic and unique in their feeding method: the antennae of phantom midge larvae are modified into grasping organs slightly resembling the raptorial arms of a mantis, with which they capture prey. They feed largely on small insects such as mosquito larvae and crustaceans such as Daphnia. The antennae impale or crush the prey, and then bring it to the larval mouth, or stylet.
The larvae swim and sometimes form large swarms in their lacustrine habitats.Chironominae
Chironominae is a subfamily of midges in the non-biting midge family (Chironomidae).Chironomini
Chironomini is a tribe of midges in the non-biting midge family (Chironomidae).Chironomoidea
The Chironomoidea are a superfamily within the order Diptera, suborder Nematocera, infraorder Culicomorpha. This superfamily contains the families Chironomidae, Ceratopogonidae, Simuliidae, and Thaumaleidae. One of the more important characteristics used to define them is the form of the larval mouthparts.Chironomus
Chironomus is a genus of nonbiting midges in the subfamily Chironominae of the bloodworm family, Chironomidae, containing several cryptic species that can only be distinguished by experts based on the characteristics of their giant chromosomes. The larvae of several species inhabit the profundal zone where they can reach relatively high densities. They use a combination of hemoglobin-like proteins and undulatory movements in their burrows to obtain oxygen in poorly oxygenated habitats.Diamesa
Diamesa is a genus of non-biting midges in the subfamily Diamesinae of the bloodworm family Chironomidae.Diamesinae
Diamesinae is a subfamily of midges in the non-biting midge family (Chironomidae).Endochironomus
Endochironomus is a genus of non-biting midges in the subfamily Chironominae of the bloodworm family Chironomidae. It is found throughout Europe and North America.Glyptotendipes
Glyptotendipes is a genus of non-biting midges in the subfamily Chironominae of the bloodworm family Chironomidae.Midge
Midge is a term used to refer to many species of small flies. The term "midge" does not define any particular taxonomic group, but includes species in several families of non-mosquito Nematoceran Diptera. They are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midges, such as many Phlebotominae (sand fly) and Simuliidae (black fly), are vectors of various diseases. Many others play useful roles as prey items for insectivores, such as various frogs and swallows. Others are important as detritivores, participating in various nutrient cycles. The habits of midges vary greatly from species to species, though within any particular family, midges commonly have similar ecological roles.
Examples of families that include species of midges include:
Blephariceridae, net-winged midges
Cecidomyiidae, gall midges
Ceratopogonidae, biting midges (also known as no-see-ums or punkies in North America, and sandflies in Australia)
Chaoboridae, phantom midges
Chironomidae, non-biting midges (also known as muckleheads or muffleheads in the Great Lakes region of North America)
Deuterophlebiidae, mountain midges
Dixidae, meniscus midges
Scatopsidae, dung midges
Theumaleidae, solitary midgesOle A. Sæther
Ole Anton Sæther (9 December 1936 – 8 January 2013) was a Norwegian entomologist.He was scientific assistant and university lecturer at Department of Limnology, University of Oslo, from 1960 to 1966; research scientist at Freshwater Institute, Winnipeg, Manitoba, Canada from 1966-1977; and professor of systematic zoology in the Museum of Zoology at the University of Bergen from 1977 to his retirement in 2006.He specialized in aquatic Diptera, especially Chironomidae and Chaoboridae. He penned about 265 academic publications (more than 5500pages); authored or co-authored 3 subfamilies, 42 genera or subgenera and more than 300 species; and was a member of the editorial board of the journals Aquatic Insects and Acta Zoologicae Academiae Scientarum Hungaricae. He received an honorary degree at Nankai University in 2000, and was an honorary member of the Finnish Entomological Society.The festschrift Contributions to the Systematics and Ecology of Aquatic Diptera: A Tribute to Ole A. Sæther was released for his seventieth birthday. The genera Saetheria, Saetheriella, Saetheromyia, Saetherocladius, Saetherocryptus, Saetherops, Oleia, and Olecryptotendipes and the species Diamesa saetheri, Protanypus saetheri, Propsilocerus saetheri, Hydrobaenus saetheri, Limnophyes saetheri, Nanocladius saetheri, Orthocladius saetheri, Tanytarsus saetheri, and Tokunagaia oleantoni have been named after him. His contributions to Fauna Europaea, as an expert on Chironomidae, were much appreciated.
He resided in Ulriksdal 1, Bergen.Orthocladiinae
Orthocladiinae is a subfamily of midges in the non-biting midge family (Chironomidae). For lack of a better common name, they are simply referred to as orthoclads.Pentaneurini
Pentaneurini is a tribe of midges in the non-biting midge family (Chironomidae).Polypedilum
Polypedilum is a genus of non-biting midges in the subfamily Chironominae of the bloodworm family Chironomidae. This is probably the most species-rich of all chironomid genera. Larvae of Polypedilum may also be among the most abundant invertebrates in euthrophic ponds, reaching densities of up to 1200 larvae per square meter.Rasmus Carl Staeger
Rasmus Carl Staeger (1800–1875) was a Danish entomologist.
Staeger was born and died in Copenhagen, over the course of his life serving as a judge, financial advisor to the Danish government, and entomologist, focusing on Diptera. His foci were Dolichopodidae, Sepsidae and Chironomidae.Tanypodinae
Tanypodinae is a subfamily of midges in the non-biting midge family (Chironomidae). The larvae are generally carnivorous and their mouthparts are adapted for predation on small invertebrates (including other chironomid larvae) although 1st and 2nd instar larvae also feed on algae.Thaumaleidae
Thaumaleidae, the solitary midges or trickle midges, are a group of nematoceran flies related to the Ceratopogonidae, Chironomidae, and the Simuliidae. They are small, stocky, yellow to brown flies (3–4 mm). Very few species are known for this family (about 120 species in five genera). Larvae are found in films on rocks and the nonfeeding adults are usually found on foliage along the same streams in which the larvae are found. A few solitary midges are found in the Southern Hemisphere, but Thaumaleidae are generally an Holarctic family.
Extant Diptera families