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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Insect wings are adult outgrowths of the insectexoskeleton that enable insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwings, respectively, though a few insects lack hindwings, even rudiments. The wings are strengthened by a number of longitudinal veins, which often have cross-connections that form closed "cells" in the membrane (extreme examples include the dragonflies and lacewings). The patterns resulting from the fusion and cross-connection of the wing veins are often diagnostic for different evolutionary lineages and can be used for identification to the family or even genus level in many orders of insects.
Physically, some insects move their flight muscles directly, others indirectly. In insects with direct flight, the wing muscles directly attach to the wing base, so that a small downward movement of the wing base lifts the wing itself upward. Those insects with indirect flight have muscles that attach to and deform the thorax, causing the wings to move as well.
The wings are present in only one sex (often the male) in some groups such as velvet ants and Strepsiptera, or are selectively lost in "workers" of social insects such as ants and termites. Rarely, the female is winged but the male not, as in fig wasps. In some cases, wings are produced only at particular times in the life cycle, such as in the dispersal phase of aphids. Wing structure and colouration often vary with morphs, such as in the aphids, migratory phases of locusts and polymorphic butterflies. At rest, the wings may be held flat, or folded a number of times along specific patterns; most typically, it is the hindwings which are folded, but in a few groups such as the vespid wasps, it is the forewings. (Full article...)
Evarcha seyun, the Bull's Eye Jumper, is a species of jumping spider in the genusEvarcha that is endemic to the Arabian Peninsula. It seems to be common across many of the Emirates of the United Arab Emirates and al-Mahrah and Hadramaut Governorates of Yemen. The species was first described in 2007 by Wanda Wesołowska and Antonius van Harten. The spider is small, with a cephalothorax that measures between 2.2 and 2.6 mm (0.09 and 0.10 in) long and an abdomen that is between 2 and 2.7 mm (0.08 and 0.11 in) long. The female is hairier than the male. The female spider is generally brown with a darker eye field, while the male is dark brown with a black eye field. Both have legs that are black, orange and yellow. They can be distinguished from the closely related Evarcha praeclara by the patterns on their body, including a semi-lunar marking in the middle of its carapace and a light stripe on its abdomen. The species also has distinctive copulatory organs. The female has a characteristic depression in the middle of its epigyne and narrow insemination ducts that lead to complex spermathecae. The male has a spade-like apophysis that accompanies its embolus and a short blunt tibial apophysis. (Full article...)
Bees can suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals, particularly insecticides, as well as a variety of naturally occurring chemicals from plants, such as ethanol resulting from the fermentation of organic materials. Bee intoxication can result from exposure to ethanol from fermented nectar, ripe fruits, and manmade and natural chemicals in the environment.
The effects of alcohol on bees are sufficiently similar to the effects of alcohol on humans that honey bees have been used as models of human ethanol intoxication. The metabolism of bees and humans is sufficiently different that bees can safely collect nectars from plants that contain compounds toxic to humans. The honey produced by bees from these toxic nectars can be poisonous if consumed by humans. In addition, natural processes can introduce toxic substances into honey produced from nontoxic nectar. (Full article...)
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Abantiades latipennis, known as the Pindi moth, is a species of moth in the family Hepialidae. It may also be referred to as a swift moth or a ghost moth, as this is a common name associated with Hepialidae. Endemic to Australia and identified in 1932, it is most populous in temperate rainforest where eucalypti are prevalent, as the larvae feed primarily on the roots of these trees. Females lay eggs during flight in a scattering fashion. The larvae live for over eighteen months underground, while adult moths survive for approximately one week, as they have no mouthparts with which to feed. The moths are preyed upon by a number of predators, including bats and owls. Brown in colour overall, males are paler and the identifying silver bars of the male's wings are more prominent than those of the female's, with dark margins. Male adults are generally smaller.
Established clearfelling practices have been shown to favour the Pindi moth, and could lead to it being considered a pest due to opportunistic proliferation of the species. The resulting damage caused to the trees on which it feeds may be considered significant. (Full article...)
Out of the four described species of Slimonia, three measured below or up to 20 centimetres (7.9 in) in length. Only S. acuminata was larger, with the largest specimens measuring 100 centimetres (39 in) in length. Though this is large for a predatory arthropod, Slimonia would be exceeded in length by later and more derived (more "advanced") members of the closely related pterygotid family of eurypterids, which would become the largest known arthropods to ever live. (Full article...)
Afraflacilla refulgens is a species of jumping spider in the genusAfraflacilla that lives in Zimbabwe. It lives in loose conglomerations in nests of white papery silk and is particularly visible in September and October. The males will display to each other, but will retreat if they feel threatened. A small spider, it has a dark carapace that is between 1.7 and 2.2 mm (0.067 and 0.087 in) long and an abdomen between 1.9 and 3.0 mm (0.075 and 0.118 in) long. It has a very dark, nearly black, eye field, although the male has a very thin white line behind the first row of eyes. The legs are generally yellow, apart from the front pair on the male, which are brown, longer and stouter and used for stridulation. The male abdomen is black with a pattern of white spots. The female abdomen is very dark brown, nearly black at the front and yellow to the rear. Both have a distinctive iridescent patch at the back of the abdomen that is recalled in the name of the species, which is a Latin word that can be translated "brilliant". It is this iridescent patch that helps to distinguish the species, although a study of the copulatory organs is needed to confirm its identity. The spider was first described in 2008 by Wanda Wesołowska and Meg Cumming. Originally allocated to the genus Pseudicius, it was moved to its current name by Jerzy Prószyński in 2016. (Full article...)
Evarcha denticulata, the Paterson Evarcha Jumping Spider, is a species of jumping spider that is endemic to South Africa. A member of the genusEvarcha, it is ground-dwelling spider, thriving in the fynbos found in the Eastern and Western Capes. The spider is small, with a rounded forward section, or cephalothorax, that is usually between 2.1 and 2.5 mm (0.08 and 0.10 in) long and, behind that, an ovoid abdomen that is between 1.8 and 3.4 mm (0.07 and 0.13 in) long. The female has a larger abdomen than the male. It is also lighter, with a pattern of grey patches visible on its yellow background. The male is generally blackish-brown. Both have three lines of white hairs on the spider's cheeks. The male Evarcha denticulata has a distinctive tooth on the spike, or apophysis, that emanates from its palpal tibia, part of its copulatory organs, which is recalled in the specific name. The species was first described in 2013 by Wanda Wesołowska and Charles Hadded. (Full article...)
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Phaeacius lancearius
Phaeacius is a spidergenus of the family Salticidae (jumping spiders), found in sub-tropical China and between India and the Malay Peninsula, including Sri Lanka, Sumatra and the Philippines. Although other spiders can jump, salticids including Phaeacius have significantly better vision than other spiders, and their main eyes are more acute in daylight than a cat's and 10 times more acute than a dragonfly's. The main eyes focus accurately on an object at distances from approximately 2 centimetres (0.79 in) to infinity, and in practice can see up to about 75 centimetres (30 in). They do not spin webs.
While most jumping spiders are active hunters, Phaeacius is unusually sedentary, generally resting in its unusual flattened pose for hours or days on logs, tree trunks, pieces of wood or any other solid surface, where it is very well camouflaged. Its preferred prey is moths and other insects, and jumping spiders. Insects can usually move around an inactive Phaeacius, or even over its body, but if the insect moves between the spider's first pair of legs, Phaeacius lunges extremely quickly to bite the prey. Sometimes Phaeacius takes a more active approach, especially if without prey for a week or more. Phaeacius does not enter webs voluntary, and moves away if it touches one accidentally. It can bite through the threads and pull strongly with its legs, but cannot escape from very sticky webs.
The Colorado potato beetle (Leptinotarsa decemlineata; also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle, and the potato bug) is a beetle known for being a major pest of potato crops. It is about 10 mm (3⁄8 in) long, with a bright yellow/orange body and five bold brown stripes along the length of each of its wings. Native to the Rocky Mountains, it spread rapidly in potato crops across the United States and then Europe from 1859 onwards.
The purple shore crab (Hemigrapsus nudus or the naked shore crab) is a common crab of the family Varunidae that is indigenous to the west coast of United States, Canada, and Mexico. H. nudus was first described in 1847 by Adam White, and in 1851, James Dwight Dana formally classified the species. H. nudus is a small, amphibious crab that is similar physically and behaviorally to Pachygrapsus crassipes and Hemigrapsus oregonensis. The purple shore crab is generally a dark purple color with olive green, red, and white spots. Mating season for H. nudus begins in mid-winter and larval crabs undergo 5 zoeal stages and a juvenile stage. Adult crabs mainly feed on algae but will occasionally scavenge other animals. H. nudus prefers inter-tidal and sub-tidal zones, and it can oftentimes be found sheltering under rocks or other debris. H. nudus demonstrates complex compensatory mechanisms to counteract fluctuating salinity and water oxygen concentrations, permitting it to live in a variety of different environments. (Full article...)
Insects have a three-part body: head with large compound eyes and antennae, a thorax with three pairs of legs, and a segmented abdomen. Many groups also have two pairs of wings.
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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Holotype specimen
Keurbos is an extinct genus of enigmatic arthropods from the latest Ordovician (Hirnantian) Soom Shale of South Africa, a Lagerstätten fossil site within the larger Cederberg Formation. The genus contains a single species, Keurbos susanae. It is known from two specimens, one nearly complete and the other a partial body. These specimens, while preserving the internal organs extremely well, barely preserve the exoskeleton. At about 43 centimetres (17 in) long, Keurbos is a large arthropod. Its trunk has 46 segments that decrease in size toward the rear. Its exact phylogenetic placement in relation to other arthropods is uncertain due to the poor preservation of the head and limbs. Keurbos inhabited a cold ocean basin, having lived right after a major glaciation. (Full article...)
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Helicoverpa zea, commonly known as the corn earworm, is a species (formerly in the genus Heliothis) in the family Noctuidae. The larva of the mothHelicoverpa zea is a major agricultural pest. Since it is polyphagous (feeds on many different plants) during the larval stage, the species has been given many different common names, including the cotton bollworm and the tomato fruitworm. It also consumes a wide variety of other crops.
The species is widely distributed across the Americas with the exception of northern Canada and Alaska. It has become resistant to many pesticides, but can be controlled with integrated pest management techniques including deep ploughing, trap crops, chemical control using mineral oil, and biological controls.
The species migrates seasonally, at night, and can be carried downwind up to 400 km. Pupae can make use of diapause to wait out adverse environmental conditions, especially at high latitudes and in drought. (Full article...)
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Fossil carapace and portions of the abdomen of R. vaningeni
Rhinocarcinosoma is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Rhinocarcinosoma have been discovered in deposits ranging of Late Silurian age in the United States, Canada and Vietnam. The genus contains three species, the American R. cicerops and R. vaningeni and the Vietnamese R. dosonensis. The generic name is derived from the related genus Carcinosoma, and the Greek ῥινός (rhinós, "nose"), referring to the unusual shovel-shaped protrusion on the front of the carapace (head plate) of Rhinocarcinosoma, its most distinctive feature.
Other than the protrusion, Rhinocarcinosoma was anatomically very similar to its close relative, Eusarcana, though it lacked the scorpion-like telson (the posteriormost division of the body) of that genus. Further distinguishing features include more slender appendages and slightly different ornamentation of scales. In terms of size, Rhinocarcinosoma was a medium-sized carcinosomatid eurypterid, with the largest species, R. vaningeni, reaching lengths of 39 centimetres (15.4 in).
In contrast to other carcinosomatids, Rhinocarcinosoma is not known only from marine settings, but also from deposits that were once lakes or rivers. It was adapted to a bottom-dwelling lifestyle, as either a burrowing or digging scavenger or top predator, feeding on other invertebrates and small fish. (Full article...)
... that in the burrowing wolf spiderAllocosa brasiliensis, males often eat older, less fecund females that they lured into their burrow using pheromones, while preferring to mate with virgins?
Image 7Some 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 8 Honeybee larvae have flexible but delicate unsclerotised cuticles. (from Arthropod exoskeleton)
Image 10Mature 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 20Ghost 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 22In 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 27The 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 30 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 31Body structure of a typical crustacean – krill (from Crustacean)
Image 32Formation 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 33This 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)
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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.
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 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.
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 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.
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.
Planthoppers are insects in the suborder Auchenorrhyncha. This photograph shows three adult Phromnia rosea planthoppers on a stem, with three nymphs underneath; the adults fold their wings in a tent-like fashion, while the nymphs are clad in a dense tangle of white wax threads. Both the adults and the nymphs feed by sucking sap from the host plant.
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.
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 Meadow Argus (Junonia villida) is a species of butterfly native to Australasia. Its brown wings are each covered with two distinctive black and blue eyespots as well as white and orange marks that appear on the edge of the wings. Males and females are similar in appearance and size, with females being slightly larger.
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.
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 cryptic mantis (Sibylla pretiosa) is a mantid native to southern Africa. Its common name comes from its ability to grow asymmetrically to match the vegetation of its environment. They have unusual leaf-like projections on the joint of their four walking legs and leaf-like wings, generally the only green portion of the insect's otherwise brown and mottled exoskeleton. Adult females grow to 5–6 cm (2.0–2.4 in) in length while the males are generally about 1 cm smaller.
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.
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.
Pieris brassicae, the large white, is a species of butterfly in the family Pieridae, common in Europe, Asia and North Africa. The larva pictured here, which was found at a market in Fronton, France, is a serious pest of plants in the cabbage family, Brassicaceae. The eggs are laid in batches on the undersides of the leaves of plants rich in mustard-oil glucosides, and consumption of these substances as they chew the leaves makes the larvae distasteful; the bright colouration of the larvae signals to predators that they taste bad. Additionally, the adult butterflies emit an unpleasant smell and display warning colours.
The longtail tadpole shrimp (Triops longicaudatus) is a freshwater crustacean resembling a miniature horseshoe crab. It is one of the oldest animal species still in existence. Like its relative Triops cancriformis, the longtail tadpole shrimp is considered a living fossil because its basic prehistoric morphology has changed little in the last 70 million years, exactly matching ancient fossils.
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.
Two Melangyna viridiceps (called Common Hoverflies in Australia) mating in mid-air. The male, which can be identified by the eyes meeting at the top of its head, is on top. The term "hoverfly" refers to about 6,000 species of flying insects in the family Syrphidae. They are often seen hovering at flowers and are important pollinators.
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