Compound eye of a dragonfly

A compound eye is a visual organ found in arthropods such as insects and crustaceans. It consists of one to thousands^[1] of ommatidia which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by the arthropod is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light.^[2] Image File history File links Download high-resolution version (1600x1067, 555 KB) Compound eyes of a dragonfly. ... Image File history File links Download high-resolution version (1600x1067, 555 KB) Compound eyes of a dragonfly. ... This article is about the insect. ... This article is about the biological unit. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... For the Dutch band, see Crustacean (band). ... The compound eye of insects is composed of hundreds of units called ommatidia. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... Light from a single point of a distant object and light from a single point of a near object being brought to a focus by changing the curvature of the lens. ... This article is about cellular photoreceptors. ... For other uses, see Eye (disambiguation). ... Image resolution describes the detail an image holds. ... In electrodynamics, polarization (also spelled polarisation) is the property of electromagnetic waves, such as light, that describes the direction of their transverse electric field. ...

Types

Drawing from Robert Hooke's, Micrographia of the compound eye of a grey drone fly.

Compound eyes are typically classified as either apposition eyes, that form multiple inverted images, or superposition eyes, that form a single erect image.^[3] Robert Hooke, FRS (July 18, 1635 – March 3, 1703) was an English polymath who played an important role in the scientific revolution, through both experimental and theoretical work. ... Hookes drawing of a flea Micrographia is a historical book by Robert Hooke, detailing the then twenty-eight year-old Hookes observations through various lenses. ...

e.g. A housefly's compound eyes

Superposition eyes

The second type is named the superposition eye. The superposition eye is divided into three types; the refracting, the reflecting and the parabolic superposition eye. The refracting superposition eye has a gap between the lens and the rhabdom, and no side wall. Each lens takes light at an angle to its axis and reflects it to the same angle on the other side. The result is an image at half the radius of the eye, which is where the tips of the rhabdoms are. This kind is used mostly by nocturnal insects. In the parabolic superposition compound eye design, seen in arthropods such as mayflies, the parabolic surfaces of the inside of each facet focus light from a reflector to a sensor array. Long-bodied decapod crustaceans such as shrimp, prawns, crayfish and lobsters are alone in having reflecting superposition eyes, which also has a transparent gap but uses corner mirrors instead of lenses. Suborders Suborder Schistonota  Superfamily Baetoidea    Siphlonuridae    Baetidae    Oniscigastridae    Ameletopsidae    Ametropodidae  Superfamily Heptagenioidea    Coloburiscidae    Oligoneuriidae    Isonychiidae    Heptageniidae  Superfamily Leptophlebioidea    Leptophlebiidae  Superfamily Ephemeroidea    Behningiidae    Potamanthidae    Euthyplociidae    Polymitarcydae    Ephemeridae    Palingeniidae Suborder Pannota  Superfamily Ephemerelloidea    Ephemerellidae    Leptohyphidae    Tricorythidae  Superfamily Caenoidea    Neoephemeridae    Baetiscidae    Caenidae    Prosopistomatidae Mayflies are insects which belong to the Order Ephemeroptera (from... Superfamilies Alpheoidea Atyoidea Bresilioidea Campylonotoidea Crangonoidea Galatheacaridoidea Nematocarcinoidea Oplophoroidea Palaemonoidea Pandaloidea Pasiphaeoidea Procaridoidea Processoidea Psalidopodoidea Stylodactyloidea True shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. ... Superfamilies and families Penaeoidea Aristeidae Benthesicymidae Penaeidae Sicyoniidae Solenoceridae Sergestoidea Luciferidae Sergestidae Wikispecies has information related to: Dendrobranchiata Prawns are shrimp–like crustaceans, belonging to the sub-order Dendrobranchiata [1]. Prawns are distinguished from the superficially similar shrimp by the gill structure which is branching in prawns (hence the name... Families Astacoidea   Astacidae   Cambaridae Parastacoidea   Parastacidae Crayfish, often referred to as crawfish or crawdad, are freshwater crustaceans resembling small lobsters, to which they are closely related. ... Subfamilies and Genera Neophoberinae Acanthacaris Thymopinae Nephropsis Nephropides Thymops Thymopsis Nephropinae Homarus Nephrops Homarinus Metanephrops Eunephrops Thymopides Clawed lobsters comprise a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. ... A mirror, reflecting a vase. ...

Compound eye of Antarctic krill as imaged by an electron microscope

Download high resolution version (1574x1505, 252 KB)Antarctic krill Euphausia superba (Photo by Gerd Alberti and Uwe Kils) GFDL goto large resolution File links The following pages link to this file: Scanning electron microscope Antarctic krill User talk:Jimbo Wales Eye Compound eye Image:Krilleyekils. ... Download high resolution version (1574x1505, 252 KB)Antarctic krill Euphausia superba (Photo by Gerd Alberti and Uwe Kils) GFDL goto large resolution File links The following pages link to this file: Scanning electron microscope Antarctic krill User talk:Jimbo Wales Eye Compound eye Image:Krilleyekils. ... Binomial name Dana, 1850 Antarctic krill are eaten by penguins(Euphausia superba) is a species of krill found in the Antarctic waters of the Southern Ocean. ... An electron microscope is a type of microscope that uses electrons as a way to illuminate and create an image of a specimen. ...

Other

The holoptic compound eyes of a syrphid fly (Eristalinus taeniops)

Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives acute vision. In the acute zone the eye are flattened and the facets larger. The flattening allows more ommatidia to receive light from a spot and therefore higher resolution. Holoptic refers to the way the eyes of a Diptera meet along the dorsal length of its head. ... A praying mantis, or praying mantid, is the common name for an insect of the order Mantodea. ... This article is about the insect. ...

There are some exceptions from the types mentioned above. Some insects have a so-called single lens compound eye, a transitional type which is something between a superposition type of the multi-lens compound eye and the single lens eye found in animals with simple eyes. Then there is the mysid shrimp Dioptromysis paucispinosa. The shrimp has an eye of the refracting superposition type, in the rear behind this in each eye there is a single large facet that is three times in diameter the others in the eye and behind this is an enlarged crystalline cone. This projects an upright image on a specialized retina. The resulting eye is a mixture of a simple eye within a compound eye. Any of various small, shrimplike, chiefly marine crustaceans of the order Mysidacea, the females of which carry their eggs in a pouch beneath the thorax. ...

Another version is the pseudofaceted eye, as seen in Scutigera. This type of eye consists of a cluster of numerous ocelli on each side of the head, organized in a way that resembles a true compound eye. Ocelli is one of the types of photoreceptor organs in animals. ...

The body of Ophiocoma wendtii, a type of brittle star, is covered with ommatidia, turning its whole skin into a compound eye. Binomial name Ophiocoma wendtii The brittlestar Ophiocoma wendtii inhabits coral reefs from Bermuda to Brazil. ... Orders ME Oegophiurida Ophiurida Phrynophiurida Brittle stars are echinoderms, closely related to starfish. ...

References

See also

• Rhabdom

Rhabdoms are transparent rods, found in the center of each ommatidium in the compound eye of arthropods. ...

External links

Wikimedia Commons has media related to:

Compound eye

• The Compound Eye
• Make Your Own Compound Eye by Stephanie Bailey
• Did you know that shrimps blink?