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...)
Portia labiata is a jumping spider (family Salticidae) found in Sri Lanka, India, southern China, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. In this medium-sized jumping spider, the front part is orange-brown and the back part is brownish. The conspicuous main eyes provide vision more acute than a cat's during the day and 10 times more acute than a dragonfly's, and this is essential in P. labiata′s navigation, hunting and mating.
The genusPortia has been called "eight-legged cats", as their hunting tactics are as versatile and adaptable as a lion's. All members of Portia have instinctive hunting tactics for their most common prey, but often can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach. While most jumping spiders prey mainly on insects and by active hunting, females of Portia also build webs to catch prey directly and sometimes join their own webs on to those of web-based spiders. Both females and males prefer web spiders as prey, followed by other jumping spiders, and finally insects. In all cases females are more effective predators than males.
Populations from Los Baños and from Sagada, both in the Philippines, have slightly different hunting tactics. In laboratory tests, Los Baños P. labiata relies more on trial and error than Sagada P. labiata in finding ways to vibrate the prey's web and thus lure or distract the prey. Around Los Baños the web-building Scytodes pallida, which preys on jumping spiders, is very abundant, and spits a sticky gum on prey and potential threats. A P. labiata from Los Baños instinctively detours round the back of S. pallida while with plucking the web in a way that makes the prey believe the threat is in front of it. In areas where S. pallida is absent, the local members of P. labiata do not use this combination of deception and detouring for a stab in the back. In a test to explore P. labiata′s ability to solve a novel problem, a miniature lagoon was set up, and the spiders had to find the best way to cross it. Specimens from Sagada, in the mountains, almost always repeated the first option they tried, even when that was unsuccessful. When specimens from Los Baños, beside a lake, were unsuccessful the first time, about three quarters switched to another option. (Full article...)
Mole crickets are members of the insect familyGryllotalpidae, in the orderOrthoptera (grasshoppers, locusts, and crickets). Mole crickets are cylindrical-bodied, fossorialinsects about 3–5 cm (1.2–2.0 in) long as adults, with small eyes and shovel-like fore limbs highly developed for burrowing. They are present in many parts of the world and where they have arrived in new regions, may become agricultural pests.
Mole crickets have three life stages: eggs, nymphs, and adults. Most of their lives in these stages are spent underground, but adults have wings and disperse in the breeding season. They vary in their diet: some species are herbivores, mainly feeding on roots; others are omnivores, including worms and grubs in their diet; and a few are largely predatory. Male mole crickets have an exceptionally loud song; they sing from a burrow that opens out into the air in the shape of an exponential horn. The song is an almost pure tone, modulated into chirps. It is used to attract females, either for mating, or for indicating favourable habitats for them to lay their eggs.
In Zambia, mole crickets are thought to bring good fortune, while in Latin America, they are said to predict rain. In Florida, where Neoscapteriscus mole crickets are not native, they are considered pests, and various biological controls have been used. Gryllotalpa species have been used as food in West Java, Vietnam, Thailand, Laos, and the Philippines. (Full article...)
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Aleeta curvicosta (commonly known as the floury baker or floury miller, known until 2003 as Abricta curvicosta) is a species of cicada, one of Australia's most familiar insects. Native to the continent's eastern coastline, it was described in 1834 by Ernst Friedrich Germar. The floury baker is the only described species in the genusAleeta.
The floury baker's distinctive appearance and loud call make it popular with children. Both the common and genus name are derived from the white, flour-like filaments covering the adult body. Its body and eyes are generally brown with pale patterns including a light-coloured line along the midline of the pronotum. Its forewings have distinctive dark brown patches at the base of two of their apical cells. The female is larger than the male, although species size overall varies geographically, with larger animals associated with regions of higher rainfall. The male has distinctive genitalia and a loud and complex call generated by the frequent buckling of ribbed tymbals and amplified by abdominal air sacs.
The floury baker is solitary and occurs in low densities. Individuals typically emerge from the soil through a three-month period from late November to late February, and can be encountered until May. The floury baker is found on a wide variety of trees, with some preference for species of paperbark (Melaleuca). It is a relatively poor flier, preyed upon by cicada killer wasps and a wide variety of birds, and can succumb to a cicada-specific fungal disease. (Full article...)
The caddisflies, or orderTrichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the basis of the adult mouthparts. Integripalpian larvae construct a portable casing to protect themselves as they move around looking for food, while annulipalpian larvae make themselves a fixed retreat in which they remain, waiting for food to come to them. The affinities of the small third suborder Spicipalpia are unclear, and molecular analysis suggests it may not be monophyletic. Also called sedge-flies or rail-flies, the adults are small moth-like insects with two pairs of hairy membranous wings. They are closely related to the Lepidoptera (moths and butterflies) which have scales on their wings; the two orders together form the superorder Amphiesmenoptera.
The aquatic larvae are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps and temporary waters (vernal pools), and even the ocean. The larvae of many species use silk to make protective cases, which are often strengthened with gravel, sand, twigs, bitten-off pieces of plants, or other debris. The larvae exhibit various feeding strategies, with different species being predators, leaf shredders, algal grazers, or collectors of particles from the water column and benthos. Most adults have short lives during which they do not feed.
In fly fishing, artificial flies are tied to imitate adults, while larvae and pupae are used as bait. Common and widespread genera such as Helicopsyche and Hydropsyche are important in the sport, where caddisflies are known as "sedges". Caddisflies are useful as bioindicators, as they are sensitive to water pollution and are large enough to be assessed in the field. In art, the French artist Hubert Duprat has created works by providing caddis larvae with small grains of gold and precious stones for them to build into decorative cases. (Full article...)
Cockroaches (or roaches) are insects belonging to the orderBlattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as pests.
The cockroaches are an ancient group, with their ancestors, known as "roachoids", originating during the Carboniferous period, some 320 million years ago. Those early ancestors, however, lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects lacking special adaptations (such as the sucking mouthparts of aphids and other true bugs); they have chewing mouthparts and are probably among the most primitive of living Neopteran insects. They are common and hardy insects capable of tolerating a wide range of climates, from Arctic cold to tropical heat. Tropical cockroaches are often much larger than temperate species.
Modern cockroaches are not considered to be a monophyletic group, as it has been found based on genetics that termites are deeply nested within the group, with some groups of cockroaches more closely related to termites than they are to other cockroaches, thus rendering Blattaria paraphyletic. Both cockroaches and termites are included into Blattodea. (Full article...)
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Engraving captioned Urania riphaeus from Charles D. d'Orbigny's Dictionnaire universel d'histoire naturelle (1849)
Chrysiridia rhipheus, the Madagascan sunset moth, is a species of day-flying moth of the family Uraniidae. It is considered one of the most impressive and appealing-looking lepidopterans. Famous worldwide, it is featured in most coffee table books on Lepidoptera and is much sought after by collectors, though many older sources misspell the species name as "ripheus". The colours originate from optical interference in the iridescent parts of the wings, while the black parts are pigmented. Adults have a wingspan of 7–9 cm (2.8–3.5 in).
Dru Drury, who described the moth in 1773, placed it in the genus Papilio, considering it a butterfly. Jacob Hübner placed it in the moth genus Chrysiridia in 1823. Later redescriptions led to junior synonyms such as Chrysiridia madagascariensis (Lesson, 1831).
At first the moth was thought to be from China or Bengal, but was later found to be endemic to Madagascar. It is found throughout the year in most parts of the island, with peak populations between March and August, and smallest numbers between October and December. Females lay about 80 eggs under the leaves of Omphaleaspp. The caterpillars are whitish yellow with black spots and red feet and are covered in club-ended black setae. Silk spun from the mouth helps the caterpillars hold on to smooth leaves and climb back to the plant when they fall. After completing four instars, the caterpillars spin an open network cocoon. The pupal stage lasts from 17 to 23 days. Chrysiridia rhipheus is the sole specialist herbivore of the four species of Omphalea in Madagascar. Omphalea is toxic: the toxins are sequestered by the feeding caterpillar and retained in the pupal and adult stages. Thousands of these moths migrate between the eastern and western ranges of their host plants. (Full article...)
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Artist's image
Hemigrapsus estellinensis is an extinctspecies of crab, formerly endemic to the Texas Panhandle. It was discovered by Gordon C. Creel in 1962 and was probably already extinct before his description was published in 1964, after the Estelline Salt Springs where it lived were contained by the United States Army Corps of Engineers. H. estellinensis is closely related to species from the Pacific Ocean such as Hemigrapsus oregonensis, but lived 800 km (500 mi) inland in a hypersaline spring. It differed from its relatives by the pattern of spots on its back, and by the relative sizes of its limbs. (Full article...)
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Fossil of A. cummingsi
Acutiramus is a genus of giant predatory eurypterid, an extinct group of aquatic arthropods. Fossils of Acutiramus have been discovered in deposits of Late Silurian to Early Devonian age. Eight species have been described, five from North America (including A. cummingsi, the type species) and two from the Czech Republic (with one of them potentially found in Australia as well). The generic name derives from Latinacuto ("acute" or "sharp") and Latin ramus ("branch"), referring to the acute angle of the final tooth of the claws relative to the rest of the claw.
Acutiramus is classified as part of the eurypterid family Pterygotidae, a family differentiated from other eurypterids by their flattened telsons (the most posterior segment of the body) and their modified chelicerae (frontal appendages), ending in well-developed chelae (claws). Many pterygotid eurypterids, such as Jaekelopterus and Pterygotus, grew to gigantic proportions. Acutiramus was no exception, with the largest species, A. bohemicus, surpassing 2 metres (6.6 feet) in length. All species were not this large though, with some (such as A. floweri) only reaching lengths of 20 centimetres (7.9 in).
Other giant pterygotid eurypterids, such as Jaekelopterus and Pterygotus, were very visually acute (possessed good and sharp eyesight) in a similar way to modern predatory arthropods and possessed robust and crushing chelae. Studies on the compound eyes and chelicerae of Acutiramus has revealed that it would have had a comparably low visual acuity and claws adapted for slicing and shearing, rather than crushing. This suggests that the ecological role of Acutiramus was distinct from that of other pterygotids, it potentially lived a lifestyle of ambush predation or scavenging on soft-bodied animals, feeding during the night or in otherwise low-light conditions. (Full article...)
Forfarella was very small, only reaching 1.7 centimetres (0.67 inches) of length. It had a nearly rectangular head, with its eyes being unknown but possibly represented by a tubercle in the fossil. Its abdomen consisted of an almost trapezoidal preabdomen and a long, tapering postabdomen. The telson (the posteriormost division of the body) is not preserved, but it was probably short. The appendages, known only from a few fragments, probably had swimming paddles that Forfarella used to swim actively.
The fossil of Forfarella was purchased in 1893 from a fossil collection. It was sent to the Natural History Museum in London. Decades later, in 1962, a paleontologist studied it and determined that it was a chasmataspidid, naming it Forfarella mitchelli. However, the paleontologist never formally published his findings. It would not be until 1999 when a group of three other paleontologists formally described Forfarella. Forming part of the familyDiploaspididae, it was similar to Diploaspis and other Devonian genera, although it is speculated that Forfarella may have existed during the Silurian as well. It was a lacustrine animal, meaning that it lived in lakes. (Full article...)
It is a poorly-known genus whose carapace (dorsal plate of the prosoma, head) was semiovate bordered by a marginal rim, with eyeslaterally placed, a preabdomen and postabdomen (the two halves of the abdomen) with six segments each and a short spike-like telson (which was the posteriormost division of the body). It reached a total length of 7.5 centimetres (2.9 inches). These characteristics place Tylopterella in the familyOnychopterellidae together with Onychopterella and Alkenopterus.
Tylopterella is notable for its thick ornamentation and general body surface. Its paired tubercles or knobs in the top of its second to fifth segments differentiates it from many other eurypterids. This thickness that its body possessed is due to the highly saline conditions to which Tylopterella had to adapt in the Guelph Formation; other organisms with reinforced shells have also been found in the same place. (Full article...)
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Insects, such as this scorpionfly, have a three-part body: head with large compound eyes and antennae, a thorax with three pairs of legs and often wings, and a segmented abdomen.
The insect nervous system consists of a brain and a ventral nerve cord. Most insects reproduce by laying eggs. Insects breathe air through a system of paired openings along their sides, connected to small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it is only partly contained in vessels, and some circulates in an open hemocoel. Insect vision is mainly through their compound eyes, with additional small ocelli. Many insects can hear, using tympanal organs, which may be on the legs or other parts of the body. Their sense of smell is via receptors, usually on the antennae and the mouthparts.
Nearly all insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton, so development involves a series of molts. The immature stages often differ from the adults in structure, habit and habitat. Groups that undergo four-stage metamorphosis often have a nearly immobile pupa. Insects that undergo three-stage metamorphosis lack a pupa, developing through a series of increasingly adult-like nymphal stages. The higher level relationship of the insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonfly-like insects with wingspans of 55 to 70 cm (22 to 28 in). The most diverse insect groups appear to have coevolved with flowering plants. (Full article...)
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Nephrops norvegicus, known variously as the Norway lobster, Dublin Bay prawn, shlobster (shrimp-lobster), langoustine (compare langostino) or scampi, is a slim, coral colored lobster that grows up to 25 cm (10 in) long, and is "the most important commercial crustacean in Europe". It is now the only extant species in the genus Nephrops, after several other species were moved to the closely related genus Metanephrops. It lives in the north-eastern Atlantic Ocean, and parts of the Mediterranean Sea, but is absent from the Baltic Sea and Black Sea. Adults emerge from their burrows at night to feed on worms and fish. (Full article...)
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Fossil of C. newlini, the telson is inaccurately reconstructed
Carcinosomatid eurypterids had unusual proportions and features compared to other eurypterids, with a broad abdomen, thin and long tail and spined and forward-facing walking appendages. They were not as streamlined as other groups but had considerably more robust and well developed walking appendages. In Carcinosoma, these spined walking appendages are thought to have been used to create a trap to capture prey in. The telson (the posteriormost division of the body) of Carcinosoma appears to have possessed distinct segmentation, Carcinosoma is the only known eurypterid to possess this feature.
At 2.2 meters (7.2 ft) in length, the species C. punctatum is the largest carcinosomatoid eurypterid by far and is among the largest eurypterids overall, rivalling the large pterygotid eurypterids (such as Jaekelopterus) in size. Other species of the genus were considerably smaller, with most ranging from 70 centimeters (2.3 ft) to 100 centimeters (3.3 ft) in length. (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 an honestwarning signal that the larvae were distasteful; this was co-opted as a mating signal in the adults. In a further development, female fireflies of the genus Photuris mimic the flash pattern of Photinus species 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...)
... that with a 150-millimetre (5.9 in) wingspan, Sinomeganeura is small for the griffenfly family Meganeuridae, known for species with spans over 700 mm (28 in)?
... that Petrolisthes eriomerus, when trying to escape from a predator, can cast off limbs as a diversion, with the claws of a cast limb still gripping vigorously after separation?
Image 2Some 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 10Body structure of a typical crustacean – krill (from Crustacean)
Image 11In 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)
Image 16Formation 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 18This 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 21Crab larva barely recognisable as a crab, radically changes its form when it undergoes ecdysis as it matures (from Arthropod exoskeleton)
Image 22 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 23Ghost 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 28Mature 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 29The 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)
Compound eyes on a blue bottle fly. Unlike simple eyes, which have a single concave photoreceptive surface, compound eyes consist of a number of individual lenses (called ommatidia) laid out on a convex surface; this means that they point in slightly different directions. Compound eyes provide a wide field of view and can detect fast movement, but have low resolution.
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.
Papilio polymnestor, the blue Mormon, is a species of swallowtail butterfly found in southern India and Sri Lanka. It is a woodland species, often seen on forest paths and near streams. The larvae feed on trees in the family Rutaceae, such as citrus. Young larvae are green with white markings and position themselves on the upper surface of leaves, relying on their cryptic colouring, which resembles bird droppings, for protection. Older larvae seek less conspicuous locations, and have a unique habit of securing their balance by weaving silk on the substratum. This adult male P. polymnestor butterfly was photographed in the Indian state of Kerala.
The monarch butterfly (Danaus plexippus) is one of the best-known species of butterfly. Its wings feature an easily recognizable orange and black pattern, with a wingspan of 8.9–10.2 centimetres (3½–4 in).
The Painted Lady (Vanessa cardui) is a well-known colourful butterfly, found on every continent except Antarctica. It occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn.
Two Eastern Lubber grasshoppers (Romalea guttata) mating. Native to the southeastern and south central portion of the United States, it is well known both for its size and its unique coloration. During reproduction, the male grasshopper introduces sperm into the ovipositor through its aedeagus (reproductive organ), and inserts its spermatophore, a package containing the sperm, into the female's ovipositor.
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.
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.
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.
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.
Danaus genutia, the common tiger or striped tiger, is a species of brush-footed butterfly found in Sri Lanka, India, Myanmar, south-eastern Asia and Australia. It prefers areas of moderate to heavy rainfall, and typical habitats include scrubby jungle, deciduous forests and fallow land near habitations. The insect sequesters toxins from plants, and advertises its unpalatability by having prominent markings and striking colour patterns. This adult male common tiger, of the subspecies D. g. genutia, was photographed in Kerala, India.
An assassin bug belonging to the Reduviidae family of insects. A predatory insect so named because of its tendency to wait in ambush for its prey, the assassin bug uses its long rostrum to inject a lethal saliva that liquefies the internal structures of the prey, which are then sucked out.
The head of a female Clynotis severus species of jumping spider. The eyes of a spider are called simple eyes (as opposed to compound eyes) because in each eye, a single lens collects and focuses light onto the retina. In this spider, the two largest eyes in the middle are the most acute. The remainder on the sides and on the top of its head are "secondary eyes".
The Forest scorpion (Cercophonius squama) is a scorpion native to southeastern Australia and Tasmania. The body is 25 to 40 millimetres (0.98 to 1.57 in) long, and coloured creamy yellow to orange brown with dark brown variegations. The legs are yellow with some dark brown pigment.
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.
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.
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