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53-528: See text 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

106-444: A prepupal stage, and precedes adulthood ( imago ) in insects with complete metamorphosis. The pupa is a non-feeding, usually sessile stage, or highly active as in mosquitoes. It is during the pupal stage that the adult structures of the insect are formed while the larval structures are broken down. The adult structures grow from imaginal discs . The pupal stage may last weeks, months, or even years, depending on temperature and

159-754: A dominant part of soil fauna community, particularly in wet soil habitats but also in agricultural land and in early stages of succession . Some species will use humic soils to develop as larvae on land; usually using decaying vegetation or sometimes living vegetation to survive. One genus of chironomids, Camptocladius , are known to develop as larvae in cow dung. There are also some that are known to burrow deep into soil in cases of temporary aquatic habitats or droughts. Chironomid adults are predominately found in terrestrial habitats. Chironomidae have variable feeding ecology: most species feed on algae and other small soil organisms they can filtrate. Some commensal species feed off of algae on their hosts, which also provides

212-473: A key role in homologous recombination, a process required for the accurate repair of DNA double-strand breaks. Many species of chironomids have adapted high tolerances to desiccation, particularly those inhabiting temporary aquatic habitats or places where droughts frequently occur. Anhydrobiosis, which is the resultant of complete desiccation, is the loss of most or all water in the body. Although its more common in terrestrial species, tolerance for drought within

265-543: 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. Alternatively, DNA barcoding

318-459: A protective covering for the pupa. Cocoons may be tough or soft, opaque or translucent, solid or meshlike, of various colors, or composed of multiple layers, depending on the type of insect larva producing it. Many moth caterpillars shed the larval hairs ( setae ) and incorporate them into the cocoon; if these are urticating hairs then the cocoon is also irritating to the touch. Some larvae attach small twigs, fecal pellets or pieces of vegetation to

371-460: A rainy season in aquatic environments, which would cause an increase in associated taxa, such as Ephemeroptera. There have been reports of phoretic associates with predatory aquatic insects as well in chironomids. These relationships, although uncommon, represent more steady hosts for chironomids if they are accessible. Phoresy on a predatory host has been suggested to mean a more mobile, and protective host, resulting in an easier development stage for

424-588: A result of limited mobility and defensive morphology. Although they do not have appendages designed for swimming, and most free-living movement is done through undulations, Chironomids do possess strong appendages that help them grasp onto a host. Larval Commensal chironomids have been known to compete for space on the host. This competition happens on an interspecies level, but also with other commensal and or phoretic organisms. Chironomids have been reported to compete with ciliated protozoan Ephemera danica , although this competition has resulted in niche-partitioning on

477-711: A suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae . This group is paraphyletic and contains all flies except for species from suborder Brachycera (the name meaning "short-horns"), which includes more commonly known species such as the housefly or the common fruit fly . The equivalent clade to Nematocera is the whole Diptera, with Brachycera as a subclade. Families in Nematocera include mosquitoes , crane flies , gnats , black flies , and multiple families commonly known as midges . The Nematocera typically have fairly long, fine, finely-jointed antennae. In many species, such as most mosquitoes,

530-572: A variety of behaviors during their development. Due to their species ambiguity and this diversity of behaviors, there is much controversy in research on their feeding habits, particularly as adults. 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

583-461: A very wide range of environmental stresses. They are found in high abundances in many of the habitats they live in, and represent important food sources for a variety of organisms. In addition, they are found representing a significant number of symbiotic relationships with other aquatic insects, terrestrial insects, and some plants. They are distributed, and in most cases found in high abundance globally. They are found in wide variety of habitats, from

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636-407: Is a hard skin called a chrysalis. Because chrysalises are often showy and are formed in the open, they are the most familiar examples of pupae. Most chrysalides are attached to a surface by a Velcro -like arrangement of a silken pad spun by the caterpillar , usually cemented to the underside of a perch, and the cremastral hook or hooks protruding from the rear of the chrysalis or cremaster at

689-589: Is able to distinguish most species in many taxonomic groups using divergence patterns of commonly-studied gene regions. The oldest chironomid fossil , Aenne triassica , dates back to the Late Triassic epoch . By the Late Cretaceous , chironomids were highly diverse. Tanytarsins appear in the fossil record during the Middle Eocene . Chironomids as a group are very diverse in their life histories, and exhibit

742-560: 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. Nematocera The Nematocera (the name meaning "thread-horns") are

795-496: 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. 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 making undulating movements. Adults can be pests when they emerge in large numbers. They may cause difficulty during driving if they collide with

848-644: Is not found in all individuals within a species. It is hypothesized that this overwintering difference in behavior occurs when temperature are at their lowest, and perhaps has to do with the presence of ice cover in the habitat. 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

901-441: 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 of certain species apply the resources obtained in feeding differently. Generally, Males expend

954-456: Is the pupal stage of butterflies . The term is derived from the metallic–gold coloration found in the pupae of many butterflies, referred to by the Ancient Greek term χρυσός ( chrysós ) for gold. When the caterpillar is fully grown, it makes a button of silk which it uses to fasten its body to a leaf or a twig. Then the caterpillar's skin comes off for the final time. Under this old skin

1007-512: Is the stage between the larva and adult stages. The chrysalis generally refers to a butterfly pupa although the term may be misleading as there are some moths whose pupae resembles a chrysalis, e.g.: the plume winged moths of the family Pterophoridae and some geometrid moths. A cocoon is a silk case that the larvae of moths, and sometimes other insects, spin around the pupa. A cocoon is a casing spun of silk by many moths and caterpillars , and numerous other holometabolous insect larvae as

1060-458: Is very low. 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 . Chironomid larvae can also be found in some terrestrial habitats. Many species that are terrestrial are found living in soil as

1113-463: The Ancient Greek word kheironómos , "a pantomimist". This is a large taxon of insects. Some estimates of the species numbers suggest well over 10,000 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

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1166-541: The Chironomidae is similar in both terrestrial and aquatic species. A species from Africa was found with extreme tolerance to desiccation. This species was able to completely desiccate, and within 48 hours movement was found after rehydration. This same species is able to withstand this pause in development for an extended period of time, with records of it surviving up to 17 years completely dehydrated. Chironomids can be both beneficial and nuisance to humans. In many areas of

1219-536: The Chironomidae. The group includes the wingless Belgica antarctica , the largest terrestrial animal of Antarctica . Their larvae produce silk , and Chironomus has been studied as an alternative source of silk other than the silk moth , as it is possible to extract it without killing the animal ( Ahimsa silk ). 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

1272-420: The adult male mates with a female pupa about to emerge, or with the newly moulted female; this is accompanied by other actions such as capping of the reproductive system of the female with the sphragis , denying access to other males, or by exuding an anti-aphrodisiac pheromone. Pupae are usually immobile and are largely defenseless. To overcome this, pupae often are covered with a cocoon, conceal themselves in

1325-552: 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 . In Kansas, they are known as "midges." However, they are not mosquitoes of any sort, and the term " sandflies " generally refers to various species of biting flies unrelated to

1378-475: The benefit of protection and additional mobility; particularly when their chosen host site is another predatory larval species. Some species are parasitic, and pierce the integument of its host in order to feed off of its hemolymph. 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

1431-429: The cloud of males to find a mate. These families belong to the suborder Nematocera: Eclosion The pupae of different groups of insects have different names such as chrysalis for the pupae of butterflies and tumbler for those of the mosquito family. Pupae may further be enclosed in other structures such as cocoons , nests , or shells . The pupal stage follows the larval stage, or in some cases

1484-480: The commensal organism. Some chironomids can withstand high temperatures without the need to desiccate and pause development. A Japanese species of chironomid, Tokunagayusurika akasumi, have adapted to aestivation in sediments below their habitats in the event of high temperatures. Chironomids as a whole are a relatively cold-tolerant group. Overwintering of species is found in almost all its subfamilies. Most of them cocoon during their pupation to overwinter, but this

1537-406: The environment, or form underground. Some species of Lycaenid butterflies are protected in their pupal stage by ants. Another means of defense by pupae of other species is the capability of making sounds or vibrations to scare potential predators. A few species use chemical defenses including toxic secretions. The pupae of social hymenopterans are protected by adult members of the hive. Based on

1590-622: 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 , particularly 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

1643-468: The exuvia is so thin and membranous that it becomes "crumpled" as it is shed. Measuring the timing of this emergence is of interest to chronobiologists because the process is regulated by circadian clocks in many species, necessitating different assays to measure eclosion timing. In a few taxa of the Lepidoptera, especially Heliconius , pupal mating is an extreme form of reproductive strategy in which

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1696-665: The families Nepidae , Notonectidae , and Corixidae eat Chironomidae in their aquatic phases. Additionally, predatory water beetles in families such as the Dytiscidae and Hydrophilidae have been found to feed on larval chironomids. Flying midges in their adult stage are eaten by fish and insectivorous birds, such as swallows and martins . They are also thought to be an especially important food source for tufted duck chicks during their first few days of life. They also are preyed on by bats and flying predatory insects, such as Odonata and dance flies . They form an important fraction of

1749-571: The female antennae are more or less threadlike, but the males have spectacularly plumose antennae. The larvae of most families of Nematocera are aquatic, either free-swimming, rock-dwelling, plant-dwelling, or luticolous . Some families however, are not aquatic; for instance the Tipulidae tend to be soil-dwelling and the Mycetophilidae feed on fungi such as mushrooms. Unlike most of the Brachycera,

1802-457: The forewings to help make its way out. Having emerged from the chrysalis, the butterfly will usually sit on the empty shell in order to expand and harden its wings. However, if the chrysalis was near the ground (such as if it fell off from its silk pad), the butterfly would find another vertical surface to rest upon and harden its wings (such as a wall or fence). Moth pupae are usually dark in color and either formed in underground cells, loose in

1855-700: The glaciated areas of the tallest mountains, to the deepest bodies of freshwater. Larval stages of the Chironomidae can be found in almost any aquatic or semiaquatic habitat. In fact, in many freshwater aquatic habitats, especially polluted ones, chironomids are often one of the most abundant insects found. Aquatic habitats can be marine or freshwater, the latter including treeholes , bromeliads , interstitial and benthic zones, as well as man-made sewage and artificial containers. They can also be found inhabiting plant held waters, intertidal zones, interstitial zones. Many species of chironomids are found residing in sediments or benthic levels of water bodies, where Dissolved oxygen

1908-440: The hosts body. These species do not compete for food, but rather for ideal spaces on the host. In these competitive relationships, Chironomids generally choose larger host body sizes, while the protozoans might prefer smaller hosts. In host sites that contained both species, potential micro niches were observed, as these organisms were observed to deliberately space themselves out. Generally however, it seemed that chironomids beat out

1961-520: The larvae of Nematocera have distinct heads with mouthparts that may be modified for filter feeding or chewing, depending on their lifestyles. The pupae are orthorrhaphous which means that adults emerge from the pupa through a straight, longitudinal seam in the dorsal surface of the pupal cuticle. The bodies and legs of most adult Nematocera are elongated, and many species have relatively long abdomens. Males of many species form mating swarms like faint pillars of smoke, competing for females that visit

2014-575: The macro zoobenthos of most freshwater ecosystems. They are highly tolerant to low dissolved oxygen levels and changing salinity levels, both of which are often resultant from human pollution. Thus, 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 and paleoentomologists as potential indicators of past environmental changes, including past climatic variability. Although,

2067-407: The morning. In mosquitoes, the emergence is in the evening or night. In fleas, the process is triggered by vibrations that indicate the possible presence of a suitable host. Prior to emergence, the adult inside the pupal exoskeleton is termed pharate . Once the pharate adult has eclosed from the pupa, the empty pupal exoskeleton is called an exuvia ; in most hymenopterans (ants, bees and wasps)

2120-484: The most economically important of all lepidopterans. The silk moth is the only completely domesticated lepidopteran; it does not exist in the wild. Insects that pupate in a cocoon must escape from it, and they do this either by the pupa cutting its way out, or by secreting enzymes , sometimes called cocoonase , that soften the cocoon. Some cocoons are constructed with built-in lines of weakness along which they will tear easily from inside, or with exit holes that only allow

2173-403: 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

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2226-449: The outside of their cocoon in an attempt to disguise it from predators. Others spin their cocoon in a concealed location—on the underside of a leaf , in a crevice , down near the base of a tree trunk , suspended from a twig or concealed in the leaf litter . Contrary to popular belief, larvae do not completely liquify inside the cocoon. The silk in the cocoon of the silk moth can be unraveled to harvest silk fibre which makes this moth

2279-476: The postmortem interval assessment. 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

2332-436: The presence or absence of articulated mandibles that are employed in emerging from a cocoon or pupal case, the pupae can be classified in to two types: Based on whether the pupal appendages are free or attached to the body, the pupae can be classified as one of three types: A chrysalis ( Latin : chrysallis , from Ancient Greek : χρυσαλλίς , chrysallís , plural: chrysalides , also known as an aurelia ) or nympha

2385-517: The protozoan in abundance on a host. A number of biotic and abiotic factors may affect host choice in chironomids. There is evidence that this choice is pressured by hydrological factors. A higher number of chironomids associating phoretically with Ephemeroptera during a rainy season. In the dry season, host choices seemed to diversify a great deal, with many hosts only being found in a dry season. It has been suggested that this may be due to an influx of vegetative debris and detritus that characterizes

2438-454: 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

2491-503: The results of these tests are often controversial, and there are disagreements as to how beneficial they can be in the paleoentomology world. A significant portion of the Chironomidae larvae have been reported in commensal relationships with other organisms in their ecosystems. Although little is known about host choice and preference, it's been reported widely that Ephemeroptera are typically their most commonly reported host sites. Larval Chironomids often partake in commensal behaviors as

2544-417: The soil, or their pupa is contained in a protective silk case called a cocoon . The pupa of some species such as the hornet moth develops sharp ridges around the outside called adminicula that allow the pupa to move from its place of concealment inside a tree trunk when it is time for the adult to emerge. Pupa, chrysalis, and cocoon are frequently confused, but are quite distinct from each other. The pupa

2597-438: The species of insect. For example, the pupal stage lasts eight to fifteen days in monarch butterflies . The pupa may enter dormancy or diapause until the appropriate season to emerge as an adult insect. In temperate climates pupae usually stay dormant during winter, while in the tropics pupae usually do so during the dry season . Insects emerge (eclose) from pupae by splitting the pupal case. Most butterflies emerge in

2650-526: The tip of the pupal abdomen by which the caterpillar fixes itself to the pad of silk. ( Gr. kremastos 'suspended') Like other types of pupae, the chrysalis stage in most butterflies is one in which there is little movement. However, some butterfly pupae are capable of moving the abdominal segments to produce sounds or to scare away potential predators . Within the chrysalis, growth and differentiation occur. The adult butterfly emerges (ecloses) from this and expands its wings by pumping haemolymph into

2703-480: The windshield, creating an opaque coating which obscures the driver's vision. 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. These allergic reactions have been shown to be caused by the haemolglobins that are primarily found in Chironomidae larval stages. Chironomids are highly versatile species that can tolerate

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2756-401: The wing veins. Although this sudden and rapid change from pupa to imago is often called metamorphosis , metamorphosis is really the whole series of changes that an insect undergoes from egg to adult. When emerging, the butterfly uses a liquid, sometimes called cocoonase , which softens the shell of the chrysalis. Additionally, it uses two sharp claws located on the thick joints at the base of

2809-577: The world, anglers and aquarium hobbyists use them as bait or a food source, particularly bloodworms. They are also historically important food sources for some communities in Africa. Some Chironomid larvae thrive in very heavily polluted habitats. These habitats are often man-made, and result in little to no biodiversity, which implies no natural predators present to keep midge populations at natural levels. These conditions often worsen emergence events, which also take place near human-dominated habitats. The family

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