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46-457: Tipulidae is a family of large crane flies in the order Diptera . There are more than 30 genera and 4,200 described species in Tipulidae, common and widespread throughout the world. A crane fly can usually be identified as a member of Tipulidae by its maxillary palps, which is the pair appendages that hang down from the front of its head. If the fourth segment (the farthest from the body) of

92-431: A class of simple eyes. Many kinds of holometabolous larvae bear no other form of eyes until they enter their final stage of growth. Adults of several orders of hexapods also have stemmata, and never develop compound eyes at all. Examples include fleas , springtails , and Thysanura . Some other Arthropoda , such as some Myriapoda , rarely have any eyes other than stemmata at any stage of their lives (exceptions include

138-413: A clue to their ontogenetic role is their lateral position on the head; ocelli, that in other ways resemble stemmata, tend to be borne in sites median to the compound eyes, or nearly so. Among some researchers, this distinction has led to the use of the term "lateral ocelli" for stemmata. A number of genetic pathways are responsible for the occurrence and positioning of the ocelli. The gene orthodenticle

184-458: A distinct retina, lens, and cornea. Many snails and slugs also have ocelli, either at the tips or bases of their tentacles. Some other gastropods, such as the Strombidae , have much more sophisticated eyes. Giant clams have ocelli that allow light to penetrate their mantles . Spiders do not have compound eyes, but instead have several pairs of simple eyes with each pair adapted for

230-409: A family of sawflies) are only "simple" in that they represent immature or embryonic forms of the compound eyes of the adult. They can possess a considerable degree of acuity and sensitivity, and can detect polarized light. They may be optimized for light sensitivity, as opposed to detailed image formation. In the pupal stage, such stemmata develop into fully fledged compound eyes. One feature offering

276-580: A few minutes to hours and may be accomplished in flight. The female immediately oviposits , usually in wet soil or mats of algae . Some lay eggs on the surface of a water body or in dry soils, and some reportedly simply drop them in flight. Most crane fly eggs are black in color. They often have a filament, which may help anchor the egg in wet or aquatic environments. Crane fly larvae (leatherjackets) have been observed in many habitat types on dry land and in water, including marine , brackish , and fresh water . They are cylindrical in shape, but taper toward

322-473: A name which is also used for arachnids of the family Pholcidae and the order Opiliones . The larvae of crane flies are known commonly as leatherjackets. Crane flies first appeared during the Middle Triassic , around 245 million years ago, making them one of the oldest known groups of flies, and are found worldwide , though individual species usually have limited ranges. They are most diverse in

368-404: A number of neighbouring retinulae. Some jellyfish , sea stars , flatworms , and ribbonworms have the simplest "eyes" – pigment spot ocelli – which have randomly distributed pigment, and which have no other structure (such as a cornea , or lens ). The apparent "eye color" in these animals is red or black. Certain groups such as box jellyfish have more complex eyes, including some with

414-870: A relict group that was much better represented in the Tertiary . Tipulidae probably evolved from ancestors in the Upper Jurassic , the Architipulidae, and representatives of the Limoniidae are known from the Upper Triassic . Numerous common names have been applied to the crane fly. Many of the names are more or less regional in the U.S., including mosquito hawk, mosquito eater, gallinipper, and gollywhopper. They are also known as "daddy longlegs" in English-speaking countries outside

460-443: A single lens collects and focuses an entire image onto the retina (analogous to a camera ). By other criteria, the presence of a complex retina distinguishes the vertebrate camera eye from the simple stemma or ommatidia which make up compound eyes. Additionally, not all invertebrate ocelli and ommatidium have simple photoreceptors . Many have various forms of retinula (a retina-like cluster of photoreceptor cells), including

506-425: A slender body and long, stilt-like legs that are deciduous, easily coming off the body. Like other insects, their wings are marked with wing interference patterns which vary among species, thus are useful for species identification. They occur in moist, temperate environments such as vegetation near lakes and streams. They generally do not feed, but some species consume nectar, pollen and/or water. The wingspan

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552-409: A specific task or tasks. The principal and secondary eyes in spiders are arranged in four, or occasionally fewer, pairs. Only the principal eyes have moveable retinas. The secondary eyes have a reflector at the back of the eyes. The light-sensitive part of the receptor cells is next to this, so they get direct and reflected light. In hunting or jumping spiders, for example, a forward-facing pair possesses

598-445: Is absent. The sideways-facing ocelli can be called "lateral ocelli", referring to their direction and position in the triplet, however this is not to be confused with the stemmata of some insect larvae, which are also known as lateral ocelli. A dorsal ocellus consists of a lens element ( cornea ) and a layer of photoreceptors ( rod cells ). The ocellar lens may be strongly curved or flat. The photoreceptor layer may also be separated from

644-515: Is allelic to ocelliless, a mutation that stops ocelli from being produced. In Drosophila , the rhodopsin Rh2 is only expressed in simple eyes. While (in Drosophila at least) the genes eyeless and dachshund are both expressed in the compound eye but not the simple eye, no reported 'developmental' genes are uniquely expressed in the simple eye. Epidermal growth factor receptor ( Egfr ) promotes

690-462: Is an enduring urban legend that crane flies are the most venomous insects in the world; however, they have neither venom nor the ability to bite. The myth probably arose due to their being confused with the cellar spider as they are also informally called "daddy longlegs", and although the arachnid does possess venom , it is not especially potent. Despite widely held beliefs that adult crane flies (or "mosquito hawks") prey on mosquito populations,

736-441: Is consistent with the more derived larval characters similar to those of 'higher' Diptera. The Pediciidae and Tipulidae are sister groups (the "limoniids" are a paraphyletic clade ). Specifically, Limoniidae has recently been treated by numerous authors at the rank of family, but subsequent phylogenetic analyses revealed that the remaining groups of tipulids render the group paraphyletic . The Cylindrotomidae appear to be

782-888: Is generally about 1.0 to 6.5 cm ( 1 ⁄ 2 to 2 + 1 ⁄ 2  in), though some species of Holorusia can reach 11 cm ( 4 + 1 ⁄ 4  in). The antennae have up to 19 segments. It is also characterized by a V-shaped suture or groove on the back of the thorax (mesonotum) and by its wing venation. The rostrum is long and in some species as long as the head and thorax together. Larvae occur in various habitats including marshes, springs, decaying wood, moist soil, leaf litter, fungi, vertebrate nests and vegetation. They usually feed on decaying plant matter and microbes associated with this, but some species instead feed on living plants, fungi or other invertebrates. Tipuloidea are medium to large-sized flies ( 7–35 mm, 1 ⁄ 4 – 1 + 1 ⁄ 2  in) with elongated legs, wings, and abdomen. Their colour

828-428: Is usually present. The wing has two anal veins. Sternite 9 of the male genitalia has, with few exceptions, two pairs of appendages. Sometimes appendages are also present on sternite 8. The female ovipositor has sclerotized valves and the cerci have a smooth or dentate lower margin. The valves are sometimes modified into thick bristles or short teeth. The larva is elongated, usually cylindrical. The posterior two-thirds of

874-421: Is yellow, brown or grey. Ocelli are absent. The rostrum (a snout) is short to very short with a beak-like point called the nasus (rarely absent). The apical segment of the maxillary palpi is flagelliform ( whip -like) and much longer than the subapical segment. The antennae have 13 segments (exceptionally 14–19). These are whorled, serrate, or ctenidial ( comb -like). There is a distinct V-shaped suture between

920-521: The mite family Ascidae . This is known as phoresis . Some members of the tipulid genus Tipula , such as the European crane fly, Tipula paludosa and the marsh crane fly T. oleracea are agricultural pests in Europe. The larvae of these species live in the top layers of soil where they feed on the roots , root hairs , crown, and sometimes the leaves of crops, stunting their growth or killing

966-524: The pitch and the pitch took unaccustomed spin for much of the season. The phylogenetic position of the Tipuloidea remains uncertain. The classical viewpoint that they are an early branch of Diptera —perhaps (with the Trichoceridae ) the sister group of all other Diptera—is giving way to modern views that they are more highly derived. This is thanks to evidence from molecular studies, which

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1012-427: The tropics but are also common in northern latitudes and high elevations. More than 15,500 species and over 500 genera of crane flies have been described, the majority by Charles Paul Alexander , who published descriptions of 10,890 new species and subspecies, and 256 new genera and subgenera over a period of 71 years, from 1910 to 1981. An adult crane fly, resembling an oversized male mosquito , typically has

1058-615: The U.S., not to be confused with the U.S. usages of "daddy long legs" that refer to either arachnids of the order Opiliones or the family Pholcidae . The larvae of crane flies are known commonly as leatherjackets. They are also known as Jenny long legs in Scotland. In Ireland, they are generally called 'daddy long legs' in English, whereas in Irish they are commonly known as Pilib an Gheataire , which means Skinny Philip. There

1104-426: The abdomen are glabrous , often partially sclerotized and bearing posterior spiracles. The spiracular disc is usually surrounded by lobe-like projections and anal papillae or lobes. Adults have a lifespan of 10 to 15 days. The adult female usually contains mature eggs as she emerges from her pupa , and often mates immediately if a male is available. Males also search for females by walking or flying. Copulation takes

1150-411: The adult crane fly is anatomically incapable of killing or consuming other insects. Although the adults of some species may feed on nectar, the adults of many species have such short lifespans that they do not eat at all. Ocelli The structure of an animal's eye is determined by the environment in which it lives, and the behavioural tasks it must fulfill to survive. Arthropods differ widely in

1196-638: The best resolution (and even some telescopic ability) to help spot prey from a distance. Nocturnal spiders' eyes are very sensitive in low light levels and are large to capture more light, equivalent to f/0.58 in the rufous net-casting spider . The term "ocellus" (plural ocelli) is derived from the Latin oculus (eye), and literally means "little eye". In insects, two distinct ocellus types exist: dorsal (top-most) ocelli, and lateral ocelli (often referred to as ocelli and stemmata , respectively), most insects have dorsal ocelli while stemmata are found in

1242-585: The compound eyes. Additionally, given the relatively simple neural arrangement of the eye (small number of synapses between detector and effector ), as well as the extremely large diameter of some ocellar interneurons (often the largest diameter neurons in the animal's nervous system), the ocelli are typically considered to be "faster" than the compound eyes. One common theory of ocellar function in flying insects holds that they are used to assist in maintaining flight stability. Given their underfocused nature, wide fields of view , and high light-collecting ability,

1288-405: The conclusion that, with some exceptions in predatory insects, the ocelli are incapable of perceiving proper images and are thus solely suitable for light-metering functions. Given the large aperture and low f -number of the lens, as well as high convergence ratios and synaptic gains (amplification of photoreceptor signals), the ocelli are generally considered to be far more sensitive to light than

1334-412: The dorsal ocelli vary markedly throughout insect orders. They tend to be larger and more strongly expressed in flying insects (particularly bees, wasps, dragonflies and locusts) where they are typically found as a triplet. Two ocelli are directed to either side of the head, while a central (median) ocellus is directed forwards. In some terrestrial insects (e.g. some ants and cockroaches), the median ocellus

1380-402: The exceptional acrobatic abilities of these animals. Research on the ocelli is of high interest to designers of small unmanned aerial vehicles . Designers of these craft face many of the same challenges that insects face in maintaining stability in a three-dimensional world. Engineers are increasingly taking inspiration from insects to overcome these challenges. Stemmata (singular stemma) are

1426-435: The family Tipulidae: This Tipulidae article is a stub . You can help Misplaced Pages by expanding it . Crane fly A crane fly is any member of the dipteran superfamily Tipuloidea , which contains the living families Cylindrotomidae , Limoniidae , Pediciidae and Tipulidae , as well as several extinct families. "Winter crane flies", members of the family Trichoceridae , are sufficiently different from

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1472-748: The front end, and the head capsule is often retracted into the thorax. The abdomen may be smooth, lined with hairs, or studded with projections or welt-like spots. Projections may occur around the spiracles. Larvae may eat algae, microflora, and living or decomposing plant matter, including wood. Some are predatory. Larval habitats include all kinds of freshwater, semiaquatic environments. Some Tipuloidea, including Dolichopeza , are found in moist to wet cushions of mosses or liverworts. Ctenophora species are found in decaying wood or sodden logs. Nephrotoma and Tipula larvae are found in dry soils of pasturelands, lawns, and steppe. Tipuloidea larvae are also found in rich organic earth and mud, in wet spots in woods where

1518-443: The habitats in which they live, as well as their visual requirements for finding food or conspecifics , and avoiding predators. Consequently, an enormous variety of eye types are found in arthropods to overcome visual problems or limitations. Use of the term simple eye is flexible, and must be interpreted in proper context; for example, the eyes of most large animals are camera eyes and are sometimes considered "simple" because

1564-490: The head capsule is enclosed or retracted within the prothoracic segment. The larva is metapneustic (with only one pair of spiracles , these on the anal segment of the abdomen), but often with vestigial lateral spiracles (rarely apneustic). The head capsule is sclerotized anteriorly and deeply incised ventrally and often dorsolaterally. The mandibles are opposed and move in the horizontal or oblique plane. The abdominal segments have transverse creeping welts. The terminal segments of

1610-450: The humus is saturated, in leaf litter or mud, decaying plant materials, or fruits in various stages of putrefaction. Larvae can be important in the soil ecosystem, because they process organic material and increase microbial activity. Larvae and adults are also valuable prey items for many animals, including insects, spiders , fish , amphibians , birds , and mammals . Adult crane flies may be used for transport by aquatic species of

1656-420: The large and well-developed compound eyes of the house centipedes, Scutigera ). Behind each lens of a typical functional stemma lies a single cluster of photoreceptor cells, termed a retinula. The lens is biconvex , and the body of the stemma has a vitreous or crystalline core. Although stemmata are simple eyes, some kinds (such as those of the larvae of Lepidoptera and especially those of Tenthredinidae ,

1702-768: The larvae of some insect orders. Despite the shared name, they are structurally and functionally very different. Simple eyes of other animals may also be referred to as ocelli, but again the structure and anatomy of these eyes is quite distinct from those of insect dorsal ocelli. Dorsal ocelli are light-sensitive organs found on the dorsal surface or frontal surface of the head of many insects, including Hymenoptera ( bees , ants , wasps , sawflies ), Diptera (flies), Odonata ( dragonflies , damselflies ), Orthoptera ( grasshoppers , locusts ) and Mantodea (mantises). These ocelli coexist with compound eyes; thus, most insects possess two anatomically separate and functionally different visual pathways. The number, forms, and functions of

1748-470: The lens by a clear vitreous humour . The number of photoreceptors also varies widely, but may number in the hundreds or thousands for well-developed ocelli. In bees, locusts, and dragonflies, the lens is strongly curved; while in cockroaches it is flat. Locusts possess vitreous humour while blowflies and dragonflies do not. Two somewhat unusual features of ocelli are particularly notable and generally common between insect orders. These two factors have led to

1794-484: The maxillary palp is longer than the other three combined, then it is likely to be a member of Tipulidae. Also, there are usually 13 segments in the antennae of large crane flies, compared to 14 or 16 in the common limoniid crane flies . The oldest fossils that can be assigned confidently to Tipulidae sensu stricto are those of the genus Tipunia , which date to the Late Jurassic . These 39 genera belong to

1840-413: The mesonotal prescutum and scutum (near the level of the wing bases). The wings are monochromatic, longitudinally striped or marbled. In females the wings are sometimes rudimentary. The sub-costal vein (Sc) joins through Sc2 with the radial vein, Sc1 is at most a short stump. There are four, rarely (when R2 is reduced) three branches of the radial vein merging into the alar margin. The discoidal wing cell

1886-488: The ocelli are superbly adapted for measuring changes in the perceived brightness of the external world as an insect rolls or pitches around its body axis during flight. Locusts and dragonflies in tethered flight have been observed to try and "correct" their flight posture based on changes in light. Other theories of ocellar function have ranged from roles as light adaptors or global excitatory organs to polarization sensors and circadian entrainers . Recent studies have shown

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1932-442: The ocelli of some insects (most notably the dragonfly, but also some wasps) are capable of "form vision" similar to camera eyes, as the ocellar lens forms an image within, or close to, the photoreceptor layer. In dragonflies it has been demonstrated that the receptive fields of both the photoreceptors and the second-order neurons can be quite restricted. Further research has demonstrated these eyes not only resolve spatial details of

1978-403: The ommatidia of most insects and the central eyes of camel spiders . Jumping spiders and some other predatory spiders with seemingly simple eyes also emulate retinal vision in various ways. Many insects have unambiguously compound eyes consisting of multiple lenses (up to tens of thousands), but achieve an effect similar to that of a camera eye, in that each ommatidium lens focuses light onto

2024-591: The plants. They are pests on a variety of commodities. Since the late 1900s, T. paludosa and T. oleracea have become invasive in the United States. The larvae have been observed on many crops, including vegetables, fruits, cereals, pasture, lawn grasses, and ornamental plants . In 1935, Lord's Cricket Ground in London was among venues affected by leatherjackets. Several thousand were collected by ground staff and burned, because they caused bald patches on

2070-660: The typical crane flies of Tipuloidea to be excluded from the superfamily Tipuloidea, and are placed as their sister group within Tipulomorpha . The classification of crane flies has been varied in the past, with some or all of these families treated as subfamilies, but the following classification is currently accepted. (Species counts are approximate, and vary over time.) In colloquial speech, crane flies are known as mosquito hawks or " skeeter-eaters ", though they do not actually prey on adult mosquitos or other insects. They are also sometimes called " daddy longlegs ",

2116-443: The world, but also perceive motion. Second-order neurons in the dragonfly median ocellus respond more strongly to upwards-moving bars and gratings than to downwards-moving bars and gratings, but this effect is only present when ultraviolet light is used in the stimulus; when ultraviolet light is absent, no directional response is observed. Dragonfly ocelli are especially highly developed and specialised visual organs, which may support

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