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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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 8.65mm (0.27 and 0.34in), 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...)
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Spider image from a conchshell gorget at the Great Mound at Spiro, Oklahoma Throughout history, spiders have been depicted in popular culture, mythology, and symbolism. From African folklore to Greek mythology, the spider has been used to represent a variety of things, and endures into the present day with characters such as Shelob from The Lord of the Rings and Spider-Man from the eponymous comic series. It is also a symbol of mischief and malice for its toxic venom and the slow death it causes, which is often seen as a curse. In addition, the spider has inspired creations from an ancient geoglyph to a modern steampunkspectacle. Spiders have been the focus of fears, stories and mythologies of various cultures for centuries.
The spider has symbolized patience and persistence due to its hunting technique of setting webs and waiting for its prey to become ensnared. Numerous cultures attribute the spider's ability to spin webs with the origin of spinning, textile weaving, basket weaving, knotwork, string games and net making. Spiders are associated with creation myths because they seem to weave their own artistic worlds. Philosophers often use the spider's web as a metaphor or analogy, and today, terms such as the Internet or World Wide Web evoke the inter-connectivity of a spider web.
His class syllabus on zoology was originally designed for students at Berkeley, but were later published as an invertebrate zoology textbook and field guide, becoming the first compendium of marine invertebrates in the north central California coastal region for specialists working in the area between Hopkins Marine Station and Bodega Marine Laboratory. After Light's death, the book was edited, revised, and expanded by Ralph I. Smith and other contributors, becoming known as Light's Manual. After Smith himself died, the book was renamed the Light and Smith Manual in his honor. (Full article...)
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Silhouette Island and the neighboring islands
Afrolychas braueri, commonly known as the Seychelles forest scorpion, is a species of scorpion in the family Buthidae. It is currently thought to survive only on Silhouette Island, Seychelles, although the species was historically found on two additional Seychellois islands. This scorpion lives in leaf litter in forests that are largely unaffected by invasive plant species. It is a small yellowish-brown scorpion with three prominent keels on the dorsal surface of its mesosoma, which distinguishes it from other scorpions. While not much is known about the Seychelles forest scorpion's ecology due to the paucity of sightings, it is known to rely solely on its venom to capture its prey and defend its young. Its venom is not dangerous to humans.
The Seychelles forest scorpion has only been observed a handful of times and as such is believed to live in very low population densities. It is listed as a critically endangered species by the International Union for Conservation of Nature and is one of the most endangered scorpion species in the world. It is thought to be primarily threatened by invasive plant species, particularly Cinnamomum verum, degrading its habitat. Its entire known range is protected by Silhouette National Park, and recent conservation efforts on the island include vegetation restoration and the removal of cinnamon. (Full article...)
The orderEmbioptera, commonly known as webspinners or footspinners, are a small group of mostly tropical and subtropicalinsects, classified under the subclassPterygota. The order has also been called Embiodea or Embiidina. More than 400 species in 11 families have been described, the oldest known fossils of the group being from the mid-Jurassic. Species are very similar in appearance, having long, flexible bodies, short legs, and only males having wings.
Webspinners are gregarious, living subsocially in galleries of fine silk which they spin from glands on their forelegs. Members of these colonies are often related females and their offspring; adult males do not feed and die soon after mating. Males of some species have wings and are able to disperse, whereas the females remain near where they were hatched. Newly mated females may vacate the colony and establish a new one nearby. Others may emerge to search for a new food source to which the galleries can be extended, but in general, the insects rarely venture from their galleries. (Full article...)
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Views from above, below, and the side of female and male specimens from the Republic of the Congo
Peplometus congoensis is a species of jumping spider that was first found in Republic of the Congo, after which it is named. It was subsequently also seen in Democratic Republic of the Congo. A member of the genusPeplometus, it is a small spider with a forward section, known as a cephalothorax, that is between 1.2 and 1.7mm long and, behind that, an abdomen that is between 2.6 and 3mm long. The male is larger than the female. The spider is generally brown with black areas on the female's carapace and sternum, the top and bottom of its cephalothorax. Its abdomen has two hard plates called scuta that resemble the elytra of beetles, accentuating a similarity that the species shares with others in the genus to beetles of the genus Chrysomelidae. It can be distinguished from others in the genus by its legs. They are generally creamy or yellowish-brown with darker patches; the front legs are larger than the remainder and, in the male, black. The spider was first described by the arachnologistsWanda Wesołowska, Galina Azarkina and Konrad Wiśniewski in 2020. (Full article...)
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Caprellamutica, commonly known as the Japanese skeleton shrimp, is a species of skeleton shrimp. They are relatively large caprellids, reaching a maximum length of 50mm (2.0in). 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...)
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View from the side of a mature female from uMhlanga, South Africa
Psenuc dependens, the Common Psenuc Jumping Spider, is a species of jumping spider that is endemic to South Africa. Originally called Pseudicius dependens, the spider was first described in 2011 by Charles R. Haddad and Wanda Wesołowska. Now a member of the genusPsenuc, it has been found living close to humans, in farms and orchards. It is a small spider, the male being between 4.1 and 4.3mm (0.16 and 0.17in) long and the female slightly smaller. It has a flattened slender body with a brown carapace, the hard upper part of the front section of its body, that has a black eye field. Behind its carapace is an ovoid abdomen that is either greyish-brown or brownish-grey but marked with a distinctive pattern that differs between the sexes. The female has a pattern of patches and chevrons; the male has patches and spots. The male has a cymbium, part of its copulatory organs, that has a distinctive shape with a bulge at the end of its curved tip. This feature is the source of its specific name, which is a Latin word meaning 'hanging down'. The female has large, spherical accessory glands. (Full article...)
The species and others in its family were used in traditional apothecary preparations as "Cantharides". The insect is the source of the terpenoidcantharidin, a toxic blistering agent once used as an exfoliating agent, anti-rheumatic drug and an aphrodisiac. The substance has also found culinary use in some blends of the North African spice mix ras el hanout. Its various supposed benefits have been responsible for accidental poisonings. (Full article...)
Slimonidae or Slimoniidae (the name deriving from the type genus Slimonia, which is named in honor of Welsh fossil collector and surgeon Robert Slimon) is a family of eurypterids, an extinct group of aquatic arthropods. Slimonids were members of the superfamily Pterygotioidea and the family most closely related to the derived pterygotid eurypterids, which are famous for their cheliceral claws and great size. Many characteristics of the Slimonidae, such as their flattened and expanded telsons (the posteriormost division of their bodies), support a close relationship between the two groups.
Slimonids are defined as pterygotioid eurypterids with swimming legs similar to those of the type genus, Slimonia, and the second to fifth pair of appendages being non-spiniferous. The family contains only two genera, the almost completely known Slimonia and Salteropterus, which is known only from the telson and the metastoma (a large plate part of the abdomen).
Both slimonid genera preserve flattened and expanded telsons that end in elongated telson spikes. The discovery of several articulated specimens of Slimonia with the tail segments preserved in tight curves, suggesting that the tail segments were considerably more flexible than previously thought and would have been capable of considerable side-to-side movement. Unlike the related pterygotids, the slimonids did not possess robust and powerful cheliceral claws and as such, these telson spikes may have been the primary weaponry used by Slimonia, although this theory is considered unlikely by contemporary researchers. The telson spike of Salteropterus was likely not used as a weapon and was highly distinct and different from that of any other eurypterid. (Full article...)
Snakeflies are a group of predatoryinsects comprising the orderRaphidioptera, from Ancient Greekῥαφίς (rhaphís), meaning "needle", and πτερόν (pterón), meaning "wing", with two extant families: Raphidiidae and Inocelliidae, consisting of roughly 260 species. In the past, the group had a much wider distribution than it does now; snakeflies are found in temperate regions worldwide but are absent from the tropics and the Southern Hemisphere. Recognizable representatives of the group first appeared during the Early Jurassic. They are a relict group, having reached their apex of diversity during the Cretaceous before undergoing substantial decline.
An adult snakefly resembles a lacewing in appearance but has a notably elongated thorax which, together with the mobile head, gives the group their common name. The body is long and slender and the two pairs of long, membranous wings are prominently veined. Females have a large and sturdy ovipositor which is used to deposit eggs in some concealed location. They are holometabolous insects with a four-stage life cycle consisting of eggs, larvae, pupae and adults. In most species, the larvae develop under the bark of trees. They may take several years before they undergo metamorphosis, requiring a period of chilling before pupation takes place. Both adults and larvae are predators of soft-bodied arthropods. (Full article...)
Parasitoid wasp species differ in which host life-stage they attack: eggs, larvae, pupae, or adults. They mainly follow one of two major strategies within parasitism: either they are endoparasitic, developing inside the host, and koinobiont, allowing the host to continue to feed, develop, and moult; or they are ectoparasitic, developing outside the host, and idiobiont, paralysing the host immediately. Some endoparasitic wasps of the superfamily Ichneumonoidea have a mutualistic relationship with polydnaviruses, the viruses suppressing the host's immune defenses.
Parasitoidism evolved only once in the Hymenoptera, during the Permian, leading to a single clade called Euhymenoptera, but the parasitic lifestyle has secondarily been lost several times including among the ants, bees, and vespid wasps. As a result, the order Hymenoptera contains many families of parasitoids, intermixed with non-parasitoid groups. The parasitoid wasps include some very large groups, some estimates giving the Chalcidoidea as many as 500,000 species, the Ichneumonidae 100,000 species, and the Braconidae up to 50,000 species. Host insects have evolved a range of defences against parasitoid wasps, including hiding, wriggling, and camouflage markings. (Full article...)
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1875 cartoon by Henry Worrall depicting Kansas farmers battling giant grasshoppers
The Locust Plague of 1874, or the Grasshopper Plague of 1874, occurred in the summer of 1874 when hordes of Rocky Mountain locusts invaded the Great Plains in the United States and Canada. The locusts swarmed over an estimated 2millionsqmi (5.2millionkm2) and caused millions of dollars' worth of damage. Residents described swarms so thick that they covered the sun for up to six hours. (Full article...)
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John S. Clark (21 March 1885 – 1 June 1956) was a Scottish-born Australian entomologist and myrmecologist known for his study of Australian ants. Born in Glasgow, he developed an interest in entomology at a young age. Clark first arrived in Australia in 1905 and originally worked for the state railways in Queensland. He developed an interest in ants shortly afterwards, collecting his first specimens in North Queensland. He married his first wife, Maggie Forbes in 1908, who bore four children, and died in 1935. He married his second wife, Phyllis Marjorie Claringbulls in 1939 and had two daughters with her. On her suicide in 1943, Clark sent his daughters to an orphanage.
In 1919, Clark worked as the assistant to the entomologist on probation in the Western Australian Department of Agriculture, but in 1920, he took on this position full-time. He started to publish his first articles about pest insects and ants from 1921; in 1926 he became an entomologist at the National Museum in Melbourne, remaining there for 20 years. Clark continued to publish more articles until he resigned from the National Museum of Victoria in 1944. Living in poverty, Clark lived a reclusive life, publishing his last book in 1951. He died on 1 June 1956 at the age of 71. One of Clark's most notable achievements was describing Nothomyrmecia macrops, the most primitive living ant. Several ants have been named after him in recognition of his contributions. (Full article...)
The genus Anopheles diverged from other mosquitoes approximately 100million 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...)
Image 4This 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 10Ghost 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 11Formation 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 12The Fangs in Spiders' chelicerae are so sclerotised as to be greatly hardened and darkened (from Arthropod exoskeleton)
Image 13Decapods, from Ernst Haeckel's 1904 work Kunstformen der Natur (from Crustacean)
Image 15Life restoration of species of Lunataspis a genus of xiphosuran (the broader group which includes horseshoe crabs), dating to the Late Ordovician, around 455-445 million years ago. (from Chelicerata)
Image 16In 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 23Body structure of a typical crustacean – krill (from Crustacean)
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 25 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 29Life restoration of Megachelicerax, the oldest arthropod known to bear true chelicerae, dating to just over 500 million years ago (from Chelicerata)
Image 32Mature 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 33Life restoration of Sanctacaris (Habeliida), one of the oldest known chelicerate relatives from the mid-Cambrian Burgess Shale, around 508 million years ago. (from Chelicerata)
Image 35The 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)
Squilla mantis, a species of mantis shrimp, for sale at the fish auction of l'Ametlla de Mar in Catalonia, Spain. It is native to the Mediterranean Sea and adjacent warm parts of the Atlantic Ocean, where it burrows into muddy and sandy seabeds. It is the only native stomatopod to be fished for on a commercial scale in the Mediterranean.
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 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 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.
Zonocerus variegatus, the variegated grasshopper, is a species of grasshopper in the family Pyrgomorphidae native to tropical western and central Africa. It feeds on a wide variety of plant foods and causes damage to crops, particularly cassava, groundnuts and vegetables, as well as transmitting diseases caused by mosaic viruses between plants. This Z.variegatus grasshopper was photographed in the Bobiri Forest in Ghana.
The red rock crab (Grapsus grapsus), also known as "Sally Lightfoot", is one of the commonest crabs along the western seaboard of the Americas. John Steinbeck wrote of them, "Everyone who has seen them has been delighted with them ... These little crabs, with brilliant cloisonné carapaces, walk on their tiptoes, they have remarkable eyes and an extremely fast reaction time." He tried to catch them but to little avail. "If you walk slowly, they move slowly ahead of you in droves. If you hurry, they hurry. When you plunge at them, they seem to disappear in a puff of blue smoke."
The western honey bee (Apis mellifera) is the most common of the 7–12 species of honey bee worldwide. It is believed to have originated in either Africa or Asia, and spread naturally through Africa, the Middle East and Europe. Following human introduction into the Americas and Oceania, the species is now found on every continent except Antarctica. Humans have been collecting honey from bees for thousands of years, with evidence in the form of rock art found in France and Spain, dating to around 7000 BC. Along with other insects, the honey bee is an important pollinator, with a large number of the crop species farmed worldwide depending on it.
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 7.5cm (3in) 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.
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 head and mandibles of an Australianbull ant. Insect mandibles grasp, crush, or cut the insect’s food, or defend against predators or rivals. These mandibles move in the horizontal plane unlike those of the vertebrates.
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.
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 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).
Leptosia nina, known as the psyche, is a species of butterfly in the family Pieridae (the sulphurs, yellows and whites), found in the Indian subcontinent, southeastern Asia, and Australia. It has a small wingspan of 2.5 to 5cm (1 to 2in). The upper side of the otherwise white forewing has a large, somewhat pear-shaped, black spot; this spot is also present on the underside which is scattered with greenish dots and speckles, sometimes arranged in bands. This L.nina butterfly was photographed in Kerala, India.
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 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 Globe Skimmer (Pantala flavescens) is the most widespread dragonfly species on the planet, found between about the 40th parallels of latitude, or where the annual mean temperature is above 20°C (68°F), except in Europe where there are only occasional sightings.
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).
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