The evolutionary ancestry of arthropods dates back to the Cambrian period. The group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians (or their constituent clades) in a superphylum Ecdysozoa. Overall, however, the basal relationships of animals are not yet well resolved. Likewise, the relationships between various arthropod groups are still actively debated. Today, arthropods contribute to the human food supply both directly as food, and more importantly, indirectly as pollinators of crops. Some species are known to spread severe disease to humans, livestock, and crops. (Full article...)
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Female P. fimbriata
Portia fimbriata, sometimes called the fringed jumping spider, is a jumping spider (family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adult males are 5.2 to 6.5 millimetres long. Both sexes have a generally dark brown carapace, reddish brown chelicerae ("fangs"), a brown underside, dark brown palps with white hairs, and dark brown abdomens with white spots on the upper side. Both sexes have fine, faint markings and soft fringes of hair, and the legs are spindly and fringed. However, specimens from New Guinea and Indonesia have orange-brown carapaces and yellowish abdomens. In all species of the genusPortia, the abdomen distends when the spider is well fed or producing eggs.
The hunting tactics of Portia are versatile and adaptable. All members of Portia have instinctive hunting tactics for their most common prey, but can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach. There are differences in the hunting tactics of the regional populations of P. fimbriata. Those in Australia's Northern Territory are poor at hunting jumping spiders and better against non-salticid web-building spiders and against insects. The Sri Lanka variant is fair against other jumping spiders, and good against web spiders and insects. P. fimbriata in Queensland is an outstanding predator of other jumping spiders and of web spiders, but poor against insects. The Queensland variant use a unique "cryptic stalking" technique which prevents most jumping spider prey from identifying this P. fimbriata as a predator, or even as an animal at all. Some jumping spider prey have partial defences against the cryptic stalking technique. All types of prey spiders occasionally counter-attack, but all Portia species have very good defences, starting with especially tough skin.
When meeting another of the same species, P. fimbriata does not use cryptic stalking but displays by moving quickly and smoothly. In P. fimbriata from Queensland, contests between males usually are very brief and do no damage. Contests between Portia females are usually long and violent, and the victor may evict a loser and then eat the loser's eggs – but victorious females of P. fimbriata from Queensland do not kill and eat the losing female. If a P. fimbriata male from Queensland displays to a female, she may run away or she may charge at him.[c] If the pair reach agreement after this, they will copulate if she is mature, and if she is sub-adult he will cohabit in her nest until she finishes moulting, and then they copulate. P. fimbriata typically copulates much quicker than other jumping spiders. Unlike in other Portia species, females of P. fimbriata do not eat their mates during courting, nor during or after copulation. (Full article...)
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Fossils of P. anglicus
Pterygotus is a genus of giant predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Pterygotus have been discovered in deposits ranging in age from Middle Silurian to Late Devonian, and have been referred to several different species. Fossils have been recovered from four continents; Australia, Europe, North America and South America, which indicates that Pterygotus might have had a nearly cosmopolitan (worldwide) distribution. The type species, P. anglicus, was described by Swiss naturalist Louis Agassiz in 1839, who gave it the name Pterygotus, meaning "winged one". Agassiz mistakenly believed the remains were of a giant fish; he would only realize the mistake five years later in 1844.
Pterygotus was among the largest eurypterids. Isolated fossil remains of a large chelicera (frontal appendage) suggests that the largest known species, P. grandidentatus, reached a body length of 1.75 metres (5.7 ft). Several other species, notably P. impacatus at 1.65 metres (5.4 ft) and P. anglicus at 1.6 metres (5.2 ft) were similarly gigantic. Pterygotus was surpassed in size by other giant eurypterids. Acutiramus was able to surpass 2 metres (6.6 ft), and Jaekelopterus could reach 2.6 metres (8.5 ft). Many species were considerably smaller than the largest species, such as P. kopaninensis at 50 centimetres (20 in).
Like its close relative Jaekelopterus, Pterygotus was a large and active predator noted for its robust and enlarged cheliceral claws that would have allowed it to puncture and grasp prey and a visual acuity (clarity of vision) comparable to that of modern predatory arthropods. (Full article...)
The Lampyridae are a family of elateroid beetles with more than 2,000 described species, many of which are light-emitting. They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production of light, mainly during twilight, to attract mates. Light production in the Lampyridae is thought to have originated as a warningsignal that the larvae were distasteful. This ability to create light was then co-opted as a mating signal and, in a further development, adult female fireflies of the genus Photuris mimic the flash pattern of the Photinus beetle in order to trap their males as prey.
Fireflies are found in temperate and tropical climates. Many live in marshes or in wet, wooded areas where their larvae have abundant sources of food. While all known fireflies glow as larvae, only some species produce light in their adult stage, and the location of the light organ varies among species and between sexes of the same species. Fireflies have attracted human attention since classical antiquity; their presence has been taken to signify a wide variety of conditions in different cultures and is especially appreciated aesthetically in Japan, where parks are set aside for this specific purpose. (Full article...)
Horse-flies and deer flies are true flies in the family Tabanidae in the insectorderDiptera. The adults are often large and agile in flight. Only female horseflies bite land vertebrates, including humans, to obtain blood. They prefer to fly in sunlight, avoiding dark and shady areas, and are inactive at night. They are found all over the world except for some islands and the polar regions (Hawaii, Greenland, Iceland). Both horse-flies and botflies (Oestridae) are sometimes referred to as gadflies.
Adult horse-flies feed on nectar and plant exudates; males have weak mouthparts, but females have mouthparts strong enough to bite large animals. This is for the purpose of obtaining enough protein from blood to produce eggs. The mouthparts of females are formed into a stout stabbing organ with two pairs of sharp cutting blades, and a spongelike part used to lap up the blood that flows from the wound. The larvae are predaceous and grow in semiaquatic habitats.
Lycorma imperialis is a planthopperindigenous to parts of China and Indo-Malaysia. L. imperialis was originally discovered in 1846 by Adam White and has one recognized non-nominate subspecies, L. i. punicea. L. imperialis has undergone a number of reclassifications since its discovery and is one of four species in the genusLycorma. L. imperialis follows a hemimetabolous life cycle and will undergo a series of nymphal stages (instars) before maturing to an adult.
Lycorma imperialis and L. i. punicea are referred to as "lanternflies" or "lantern bugs" due to their crimson hindwings and their forewings, which can range from blue green to brick red. They do not, however, emit light. L. imperialis can cause substantial damage to agricultural industries due to its specialized, sap sucking mouthparts and the resulting mold that develops from its honeydew excrement. (Full article...)
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Illustration of the carapace of E. batrachophthalmus
Eocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Eocarcinosoma, E. batrachophthalmus, is known from deposits of Late Ordovician age in the United States. The generic name is derived from the related genus Carcinosoma, and the Greek eós (ἠώς) meaning 'dawn', referring to the earlier age of the genus compared to other carcinosomatid eurypterids.
Eocarcinosoma is known only from a single specimen, a well-preserved small prosoma (head). In life it would have been a very small eurypterid, given that the head measures just 2.05 centimetres (0.8 in) in length. The main distinguishing features from other carcinosomatids were the eyes being placed on the margins of the carapace (head plate) and the head being more triangular in shape than in its later relatives. Although initially believed to be an adult given the relatively small size of the eyes, some researchers believe Eocarcinosoma to represent a juvenile specimen of the eurypterid Megalograptus. (Full article...)
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Y. geinitzi worker
Yantaromyrmex is an extinctgenus of ants first described in 2013. Members of this genus are in the subfamily Dolichoderinae of the family Formicidae, known from Middle Eocene to Early Oligocene fossils found in Europe. The genus currently contains five described species, Y. constrictus, Y. geinitzi, Y. intermedius, Y. mayrianum and Y. samlandicus. The first specimens were collected in 1868 and studied by Austrian entomologist Gustav Mayr, who originally placed the fossils in other ant genera until the fossils were reviewed and subsequently placed into their own genus. These ants are small, measuring from 4 to 6 mm (0.16 to 0.24 in) in length and can be characterized by their trapezoidal shaped head-capsules and oval compound eyes that are located slightly to the rear of the capsules midpoint, with no known ocelli present. (Full article...)
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Plexippoides regius in South Korea
Plexippoides regius (Korean: 왕어리두줄깡충거미; RR: Wangeoridujulkkangchunggeomi) is a species of jumping spider in the genusPlexippoides. The species was first described by Wanda Wesołowska in 1981 based on specimens from North Korea but its distribution has been extended to include China, Russia and South Korea, with examples found as far as Sichuan. The spider is small, with a body length between 6.9 and 8.65 mm (0.27 and 0.34 in), the female being generally larger than the male. It is distinguished by the two brown lines that stretch across the back of its carapace and abdomen that is recalled in its Korean name. Otherwise, the spider varies in coloration, with some examples having an orange or yellow-brown carapace and others dark brown. The male has a long embolus that encircles the palpal bulb. The female has complex seminal ducts that lead to heavily sclerotised and many-chambered spermathecae. (Full article...)
The genus Anopheles diverged from other mosquitoes approximately 100 million years ago (mya), and, like other mosquitoes, the eggs, larvae, and pupae are aquatic. The Anopheles larva has no respiratory siphon through which to breathe, so it breathes and feeds with its body horizontal to the surface of the water. The adult mosquito hatches from the surface and feeds on the nectar of flowers; the female mosquito also feeds on blood, which animal diet allows them to carry and transmit parasites between hosts. The adult's feeding position is head-down, unlike the horizontal stance of the culicines. Anopheles are distributed almost worldwide, throughout the tropics, the subtropics, and the temperate regions of planet Earth. In hot weather, adult Anophelesaestivate, which is a state of dormancy that enables the mosquito to survive in hot dry regions, such as the Sahel. (Full article...)
Unionopterus was described in 1948 after the discovery of its only known specimen in the Karaganda Formation of Kazakhstan (at that time part of the Soviet Union). This was one of the first discoveries of eurypterids in the Soviet Union and Carboniferous eurypterids in general. It was probably a swimming organism as well as other eurypterids, although not as good as its relatives.
There are numerous factors that have made Unionopterus a problematic genus for eurypterid researchers. It has been placed in the familyAdelophthalmidae and it has even been speculated that a species of Adelophthalmus, A. dumonti, actually belongs to Unionopterus, but this cannot be confirmed. Many authors have chosen to completely ignore the genus during phylogenetic studies, making Unionopterus an enigmatic eurypterid. (Full article...)
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Caprella mutica, commonly known as the Japanese skeleton shrimp, is a species of skeleton shrimp. They are relatively large caprellids, reaching a maximum length of 50 mm (2.0 in). They are sexually dimorphic, with the males usually being much larger than the females. They are characterized by their "hairy" first and second thoracic segments and the rows of spines on their bodies. Body color ranges from green to red to blue, depending on the environment. They are omnivorous highly adaptable opportunistic feeders. In turn, they provide a valuable food source for fish, crabs, and other larger predators. They are usually found in dense colonies attached to submerged man-made structures, floating seaweed, and other organisms.
C. mutica are native to shallow protected bodies of water in the Sea of Japan. In as little as 40 years, they have become an invasive species in the North Atlantic, North Pacific, and along the coasts of New Zealand. They are believed to have been accidentally introduced to these areas through the global maritime traffic and aquaculture. Outside of their native range, C. mutica are often exclusively synanthropic, being found in large numbers in and around areas of human activity. Their ecological and economic impact as an invasive species is unknown, but they pose a serious threat to native populations of skeleton shrimp in the affected areas. (Full article...)
Ochetellus is a genus of ants first described by Steve Shattuck in 1992. He placed it in the subfamily Dolichoderinae of the family Formicidae. The ants in this genus are small and black in colour; workers measure 1.75 to 3 millimetres (0.07 to 0.12 in) in length, the males at around 1.6 millimetres (0.06 in) are smaller, and the queens are the largest, reaching 4 millimetres (0.16 in). There are seven described species and three described subspecies that mostly live in Australia in a wide variety of habitats, but some species are found in Asia. One species, Ochetellus glaber, has been introduced into New Zealand and the United States.
The colonies are found in rotten wood, in the ground, under rocks or stones and in urban areas. The ants are both diurnal and nocturnal and forage on trees, in low vegetation and into human homes, where they are regarded as pests. These ants eat a variety of foods, including fruits, insects, sucrose, nectar and bird feces. They visit various flowers and attend to a variety of butterfly larvae. The thorny devil, an Australian lizard, predominantly feeds on Ochetellus workers, and other ant species also prey on them. (Full article...)
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Herbst's 1792 illustration
The Cape lobster, Homarinus capensis, is a species of small lobster that lives off the coast of South Africa, from Dassen Island to Haga Haga. Only a few dozen specimens are known, mostly regurgitated by reef-dwelling fish. It lives in rocky reefs, and is thought to lay large eggs that have a short larval phase, or that hatch directly as a juvenile. The species grows to a total length of 10 cm (3.9 in), and resembles a small European or American lobster; it was previously included in the same genus, Homarus, although it is not very closely related to those species, and is now considered to form a separate, monotypic genus – Homarinus. Its closest relatives are the genera Thymops and Thymopides. (Full article...)
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Andreacarus voalavo is a parasiticmite found on the Malagasy rodent Voalavo gymnocaudus. First described in 2007, it is closely related to Andreacarus gymnuromys and Andreacarus eliurus, which are found on other Malagasy rodents. The length of the idiosoma, the main body, is 630 to 670 μm in females and 450 to 480 μm in males. Unlike A. eliurus, this species lacks distinct sternal glands (secretory organs) between two lyrifissures (sensory organs) on the lower part of the female body. The pilus dentilis, a sensory organ on the chelicera, is serrate, which distinguishes it from A. gymnuromys. Females of A. gymnuromys also have a less ornamented sternal shield (covering part of the underparts) and shorter setae (bristles) on the upperparts. (Full article...)
Pseudastacus (meaning "false Astacus", in comparison to the extant crayfish genus) is an extinct genus of decapod crustaceans that lived during the Jurassic period in Europe, and possibly the Cretaceous period in Lebanon. Many species have been assigned to it, though the placement of some species remains uncertain and others have been reassigned to different genera. Fossils attributable to this genus were first described by Georg zu Münster in 1839 under the name Bolina pustulosa, but the generic name was changed in 1861 after Albert Oppel noted that it was preoccupied. The genus has been placed into different families by numerous authors, historically being assigned to Nephropidae or Protastacidae. Currently, it is believed to be a member of Stenochiridae.
Reaching up to 6 cm (2.4 in) in total length, Pseudastacus was a small animal. Members of this genus have a crayfish-like build, possessing long antennae, a triangular rostrum and a frontmost pair of appendages enlarged into long and narrow pincers. Deep grooves are present on the carapace, which is around the same length as the abdomen. The surface of the carapace is usually uneven, with either small tubercles or pits. Sexual dimorphism is known in P. pustulosus, with the pincers of females being more elongated than those of the males. There is evidence of possible gregarious behavior in P. lemovices in the form of multiple individuals preserved alongside each other, possibly killed in a mass mortality event. With the oldest known record dating to the Sinemurian age of the Early Jurassic, and possible species surviving into the Cenomanian stage of the Late Cretaceous, Pseudastacus has a long temporal range and was a widespread taxon. Fossils of this animal were first found in the Solnhofen Limestone of Germany, but have also been recorded from France, England and Lebanon. All species in this genus lived in marine environments. (Full article...)
Image 6Formation of anterior segments across arthropod taxa based on gene expression and neuroanatomical observations, Note the chelicera(Ch) and chelifore(Chf) arose from somite 1 and thus correspond to the first antenna(An/An1) of other arthropods. (from Chelicerata)
Image 15The fangs in spiders' chelicerae are so sclerotised as to be greatly hardened and darkened (from Arthropod exoskeleton)
Image 16Mature queen of a termite colony, showing how the unsclerotised cuticle stretches between the dark sclerites that failed to stretch as the abdomen grew to accommodate her ovaries (from Arthropod exoskeleton)
Image 21 This fully-grown robber crab has tough fabric forming its joints, delicate biomineralized cuticle over its sensory antennae, optic-quality over its eyes, and strong, calcite-reinforced chitin armouring its body and legs; its pincers can break into coconuts (from Arthropod exoskeleton)
Image 22Crab larva barely recognisable as a crab, radically changes its form when it undergoes ecdysis as it matures (from Arthropod exoskeleton)
Image 23The house centipedeScutigera coleoptrata has rigid sclerites on each body segment. Supple chitin holds the sclerites together and connects the segments flexibly. Similar chitin connects the joints in the legs. Sclerotised tubular leg segments house the leg muscles, their nerves and attachments, leaving room for the passage of blood to and from the hemocoel (from Arthropod exoskeleton)
Image 24Some of the various hypotheses of myriapod phylogeny. Morphological studies (trees a and b) support a sister grouping of Diplopoda and Pauropoda, while studies of DNA or amino acid similarities suggest a variety of different relationships, including the relationship of Pauropoda and Symphyla in tree c. (from Myriapoda)
Image 26Ghost crab, showing a variety of integument types in its exoskeleton, with transparent biomineralization over the eyes, strong biomineralization over the pincers, and tough chitin fabric in the joints and the bristles on the legs (from Arthropod exoskeleton)
Image 30This Zoea-stage larva is hardly recognisable as a crab, but each time it sheds its cuticle it remodels itself, eventually taking on its final crab form (from Arthropod exoskeleton)
Image 33In honeypot antrepletes, the abdomens of the workers that hold the sugar solution grow vastly, but only the unsclerotised cuticle can stretch, leaving the unstretched sclerites as dark islands on the clear abdomen (from Arthropod exoskeleton)
The light blue soldier crab (Mictyris longicarpus) inhabits beaches in the Indo-Pacific region. Soldier crabs filter sand or mud for microorganisms. They congregate during the low tide, and bury themselves in a corkscrew pattern during high tide, or whenever they are threatened.
The rose chafer (Cetonia aurata) is a reasonably large beetle (20 mm/¾ in long) that has metallic green coloration with a distinct V shaped scutellum, the small triangular area between the wing cases just below the thorax. Rose chafers are found over southern and central Europe and the southern part of the UK.
The Ozyptila praticola species of crab spider is found throughout Europe and the Middle East. They do not build webs to trap prey, but are active hunters. Crab spiders are so named because of their first two pairs of legs, which are held out to the side giving them a crab-like appearance. Also, like crabs, these spiders move sideways and backwards more easily than forwards.
The orb-weaver spiders (family Araneidae) are the familiar builders of spiral wheel-shaped webs often found in gardens, fields and forests. The family is a large one, including over 2800 species in over 160 genera worldwide, making it the third largest known (behind Salticidae and Linyphiidae). The web has always been thought of as an engineering marvel.
Attacus taprobanis is a species of moth in the family Saturniidae native to southern India and Sri Lanka. This adult male, photographed in Kadavoor, Kerala, developed from a larva feeding on a mahogany tree. When ready to pupate, the larva formed a papery cocoon 7.5 cm (3 in) long interwoven with a leaf; before doing this, the larva had attached the leaf to the stem with a silken thread and cut the leaf stalk. The colours of the dying leaf provided camouflage for the pupa, and the adult insect emerged some 24 days later.
A macro shot of the head of a dragonfly, focusing on its compound eyes. Dragonfly eyes have up to 30,000 facets; each one is a separate light-sensing organ or ommatidium, arranged to give nearly a 360° field of vision.
Argiope trifasciata, the banded garden or banded orb-weaving spider, is a species of arachnid in the family Araneidae. It is native to North and South America but has spread to other parts of the world. This ventral view of a female A. trifasciata shows her in the centre of her web, which can reach a diameter of 60 cm (24 in). The function of the zig-zag web decorations is unclear, but they may serve to make the spider appear larger or to act as a warning sign.
A lithograph by Sidney Hall, published in Urania's Mirror, depicting the constellation Scorpius. One of the 48 constellations identified by the Greek astronomer Ptolemy in the second century, Scorpius lies between Libra to the west and Sagittarius to the east. It contains 18 main stars, the brightest of which is Antares. Although frequently identified as a scorpion, this constellation has also been likened to a "leaning coconut tree" (Java) or "Maui's fishhook" (Hawaii).
The citrus root weevil (Diaprepes abbreviatus) is a major agricultural pest weevil in several Caribbean countries and the U.S. state of Florida. The larvae feed on the roots of the host plant for several months. They often eat the taproot of the plant, which can kill it by depriving it of water and nutrients or by making it vulnerable to infection by fungi, or water moulds.
Sympetrum danae, the black darter or black meadowhawk, is a species of dragonfly found in northern Europe, Asia, and North America. Both sexes are black and yellow, but the abdomen of the male is largely black while that of the female is largely yellow. Breeding takes place in shallow acidic pools, lake margins and ditches in lowland heaths and moorland bogs. The female lays her eggs during flight by dipping the tip of her abdomen into the water. The eggs hatch the following spring, the larvae developing very rapidly and emerging as adults in as little as two months. The male seen here is perched on a frond of bracken on Warren Heath in Hampshire, England.
A Eusthenia species of stonefly. The order contains almost 3,500 known species, including the only known insects that are exclusively aquatic from birth to death. Stoneflies are believed to be one of the most primitive groups of Neoptera and are found worldwide, with the exception of Antarctica.
Xylotrupes socrates (Siamese rhinoceros beetle, or "fighting beetle"), male, on a banana leaf. This scarab beetle is particularly known for its role in insect fighting in Northern Laos and Thailand.
Poli's stellate barnacle (Chthamalus stellatus) is a species of acorn barnacle common on rocky shores in South West England, Ireland, and Southern Europe. It is named after Italian scientist Giuseppe Saverio Poli. Depending upon environmental conditions and the amount of food available, it can reach up to 14 mm (0.55 in) in diameter.
The red rock crab (Grapsus grapsus) is one of the most common crabs along the western coast of the Americas. Adults are quite variable in color, including brownish-red, mottled or spotted brown, pink, yellow, bright orange and red. It feeds on algae primarily, sometimes sampling other plant matter and dead animals.
The oriental hornet (Vespa orientalis) is a social insect in the family Vespidae, found in southern Europe, northeastern Africa, and western Asia. This worker, photographed in Sha'ar Poleg Reserve in Israel, is gathering nectar from a sea squill; adults will also feed on honeydew and fruit. They also capture insects such as grasshoppers, flies and honey bees to provide a diet high in protein for the colony's brood.
A honeycomb is a mass of hexagonal prismaticwax cells built by honey bees in their hives to contain their larvae and stores of honey and pollen. Honey bees consume about 8.4 lb (3.8 kg) of honey to secrete 1 lb (0.5 kg) of wax. As such, many beekeepers attempt to conserve honeycombs where possible.
A honey bee extracts nectar from a flower using its proboscis. Tiny hairs covering the bee's body maintain a slight electrostatic charge, causing pollen from the flower's anthers to stick to the bee's hairs, allowing for pollination when the bee moves on to another flower.
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