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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Throughout history, spiders have been depicted in popular culture, mythology and in symbolism. From Greek mythology to African folklore, 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 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.
Archimyrmex is an extinctgenus of ant in the formicid subfamily Myrmeciinae, described by palaeoentomologist Theodore Cockerell in 1923. The genus contains four described species, Archimyrmex rostratus, Archimyrmex piatnitzkyi, Archimyrmex smekali and Archimyrmex wedmannae. Archimyrmex is known from a group of Middle Eocene fossils which were found in North America, South America, and Europe. The genus was initially placed in the subfamily Ponerinae, but it was later placed in Myrmeciinae; it is now believed to be the ancestor of the extant primitive genus Myrmecia from Australia. Despite this, Archimyrmex is not a member to any tribe and is regarded as incertae sedis within Myrmeciinae. However, some authors believe Archimyrmex should be assigned as incertae sedis within Formicidae. These ants can be characterised by their large mandibles and body length, ranging from 13.2 to 30 mm (0.52 to 1.18 in). They also have long, thin legs and an elongated mesosoma (thorax) and petiole. (Full article...)
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Interpretive drawing of PIN 1271/2, the holotype of Dvulikiaspis menneri
Its prosoma (head) was subquadrate (almost square) to parabolic (nearly U-shaped), with (bean-shaped) to subovate (nearly oval) eyes and surrounded by a marginal rim. The abdomen was composed by a fused buckler and a postabdomen that occupied most of the body length, while the telson (the posteriormost division of the body) was small and semicircular in shape. The appendages (limbs) were uniform. The sixth and last pair of them had a paddle-like shape and was placed in front of the midpoint of the prosoma. The largest specimen was 2.64 centimetres (1.04 inches) long.
The first fossil was described in 1959 as a new species of the eurypteridStylonurus, while the other two were discovered in 1974. It would not be until 2014 when D. menneri was recognized as a chasmataspidid genus, being placed in the familyDiploaspididae. However, Dvulikiaspis was similar to Loganamaraspis and especially Hoplitaspis, with which it could form a new separate family of chasmataspidids. (Full article...)
Wesołowska published her first work in 1981, which included the description of nine new species of spiders, the first in what would be a prolific career. She moved to the University of Wrocław to continue her studies, and completed her doctoral thesis that described 44 new species of the genus Heliophanus. She joined the faculty of the University of Wrocław in 1985, received a habilitation in 2000, and remained a tenured professor at the university until her retirement in 2020.
Her research has focused on the description, taxonomy and zoogeography of jumping spiders, and has included extensive work on African genera like Menemerus and Pachyballus. Wesołowska has identified more than 500 species, including half of all those from South Africa, and more than 20 species have been named after her. (Full article...)
Mecoptera (from the Greek: mecos = "long", ptera = "wings") is an order of insects in the superorder Holometabola with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their largest family, Panorpidae, in which the males have enlarged genitals raised over the body that look similar to the stingers of scorpions, and long beaklike rostra. The Bittacidae, or hangingflies, are another prominent family and are known for their elaborate mating rituals, in which females choose mates based on the quality of gift prey offered to them by the males. A smaller group is the snow scorpionflies, family Boreidae, adults of which are sometimes seen walking on snowfields. In contrast, the majority of species in the order inhabit moist environments in tropical locations.
The Mecoptera are closely related to the Siphonaptera (fleas), and a little more distantly to the Diptera (true flies). They are somewhat fly-like in appearance, being small to medium-sized insects with long slender bodies and narrow membranous wings. Most breed in moist environments such as leaf litter or moss, and the eggs may not hatch until the wet season arrives. The larvae are caterpillar-like and mostly feed on vegetable matter, and the non-feeding pupae may pass through a diapause until weather conditions are favorable.
Early Mecoptera may have played an important role in pollinating extinct species of gymnosperms before the evolution of other insect pollinators such as bees. Adults of modern species are overwhelmingly predators or consumers of dead organisms. In a few areas, some species are the first insects to arrive at a cadaver, making them useful in forensic entomology. (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 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...)
Mysida is an order of small, shrimp-like crustaceans in the malacostracansuperorderPeracarida. Their common nameopossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.
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.
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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Illustration of In.43786, the holotype (and only known) specimen of N. salweyi.
Historically classified as either a millipede or a crustacean (hence the name) and once considered to potentially represent the oldest myriapod in the fossil record, Necrogammarus was first revealed to represent a fragmentary section of a large pterygotid eurypterid in 1986 by the researcher Paul Selden. As two large pterygotids are already known from the same locality and same timespan as Necrogammarus, Erettopterus and Pterygotus, it is possible that the Necrogammarus remains, in reality, belong to one of these genera. As both genera are only diagnosed and differentiated from each other by features in body parts absent in the Necrogammarus fossil, such as the chelicerae (frontal appendages) and coxae (leg segments), it is impossible to assign Necrogammarus to either of them for the time being.
Pterygotids are 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). Regardless of its potential identity as either Pterygotus or Erettopterus, these features are likely to have been present in Necrogammarus as well, as all other members of the family possess them. (Full article...)
Louse (pl.: lice) is the common name for any member of the cladePhthiraptera, which contains nearly 5,000 species of wingless parasiticinsects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result of developments in phylogenetic research.
Chewing lice live among the hairs or feathers of their host and feed on skin and debris, whereas sucking lice pierce the host's skin and feed on blood and other secretions. They usually spend their whole life on a single host, cementing their eggs, called nits, to hairs or feathers. The eggs hatch into nymphs, which moult three times before becoming fully grown, a process that takes about four weeks. Genetic evidence indicates that lice are a highly modified lineage of Psocoptera (now called Psocodea), commonly known as booklice, barklice or barkflies. The oldest known fossil lice are from the Cretaceous. (Full article...)
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Adult female red back spider
The redback spider (Latrodectus hasselti), also known as the Australian black widow, is a species of highly venomous spider believed to originate in South Australia or adjacent Western Australian deserts, but now found throughout Australia, Southeast Asia and New Zealand, with colonies elsewhere outside Australia. It is a member of the cosmopolitan genus Latrodectus, the widow spiders. The adult female is easily recognised by her spherical black body with a prominent red stripe on the upper side of her abdomen and an hourglass-shaped red/orange streak on the underside. Females usually have a body length of about 10 millimetres (0.4 in), while the male is much smaller, being only 3–4 mm (0.12–0.16 in) long.
Mainly nocturnal, the female redback lives in an untidy web in a warm sheltered location, commonly near or inside human residences. It preys on insects, spiders and small vertebrates that become ensnared in its web. It kills its prey by injecting a complex venom through its two fangs when it bites, before wrapping them in silk and sucking out the liquefied insides. Often, it first squirts its victim with what resembles 'superglue' from its spinnerets, immobilising the prey by sticking the victim's limbs and appendages to its own body. The redback spider then trusses the victim with silk. Once its prey is restrained, it is bitten repeatedly on the head, body and leg segments and is then hauled back to the redback spider's retreat. Sometimes a potentially dangerous victim can be left to struggle for hours until it is exhausted enough to approach safely. Male spiders and spiderlings often live on the periphery of the female spiders' web and steal leftovers. Other species of spider and parasitoid wasps prey on this species. The redback is one of a number of arachnids that usually display sexual cannibalism while mating.
After mating, sperm is stored in the spermathecae, organs of the female reproductive tract, and can be used up to two years later to fertilise several clutches of eggs. Each clutch averages 250 eggs and is housed in a round white silken egg sac. The redback spider has a widespread distribution in Australia, and inadvertent introductions have led to established colonies in New Zealand, the United Arab Emirates, Japan and greenhouses in Belgium. (Full article...)
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Male M. campanulae
Megachile campanulae, known as the bellflower resin bee, is a species of bee in the family Megachilidae. Described in 1903, these solitary bees are native to eastern North America. Studies in 2013 placed them among the first insect species to use synthetic materials for making nests. They are considered mason bees, which is a common descriptor of bees in several families, including Megachilidae. Within the genus Megachile, frequently also referred to as leafcutter bees, M. campanulae is a member of the subgenus Chelostomoides, which do not construct nests from cut leaves, but rather from plant resins and other materials. Females lay eggs in nests constructed with individual cell compartments for each egg. Once hatched, the eggs progress through larval stages and subsequently will overwinter as pupae. The bees are susceptible to parasitism from several other bee species, which act as brood parasites. They are medium-sized bees and the female adults are typically larger than the males. They are important pollinators of numerous native plant species throughout their range. (Full article...)
The species occurs locally across Central Europe, Asia Minor and North Africa, where its population is considered stable. Its numbers have declined in Northern Europe, leading to its European status of "vulnerable". Its range in Britain is restricted to the south coast of Dorset, however it is locally abundant and its numbers currently are perhaps at their greatest since its discovery there.
With a wingspan of 24 to 28 millimetres, females being larger than males, the Lulworth skipper is a small butterfly, the smallest member of the genus Thymelicus in Europe and among the smallest butterflies in Britain. Aside from the size difference, the sexes are distinguished by females having a distinct circle of golden marks on each forewing. Due to their likeness to the rays around the eye of a peacock's feather, these are often known as "sun-ray" markings, and they can faintly appear on males. (Full article...)
... that the Australian jumping spider Portia fimbriata plays a deadly game of hide-and-seek with its favourite prey, Jacksonoides queenlandicus, another jumping spider?
Image 4The fangs in spiders' chelicerae are so sclerotised as to be greatly hardened and darkened (from Arthropod exoskeleton)
Image 5Mature 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 8In 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 12Some 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 14Ghost 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 16Body structure of a typical crustacean – krill (from Crustacean)
Image 17The 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 20This 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 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 22Formation 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)
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 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.
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.
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 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 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 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 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.
A macro view of a Gonia capitatafly feeding on honey, showing its proboscis and pedipalps (the two appendages protruding from the proboscis), two types of insect mouthparts. The proboscis actually comprises the labium, a quadrupedal structure, and a sponge-like labellum at the end. Flies eat solid food by secreting saliva and dabbing it over the food item. As the saliva dissolves the food, the solution is then drawn up into the mouth as a liquid. The labellum's surface is covered by minute food channels which form a tube leading to the esophagus, and food is drawn up the channels by capillary action.
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 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.
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.
Gonepteryx rhamni, also known as the common brimstone, is a butterfly in the family Pieridae. It lives throughout the Palearctic zone and is commonly found across Europe, Asia and North Africa. The butterfly relies on two species of buckthorn as hosts for its eggs and larvae, which influences its geographic range and distribution as these plants are commonly found in wetlands. After spending the summer feeding, adults travel to woodland areas to spend seven months hibernating. In spring when their host plants have developed, they return to the wetlands to breed and lay eggs. Both the larval and adult forms of the species have protective coloration and behaviour that decreases their chances of being recognised and preyed upon. The adult common brimstone has sexual dichromism in its wing coloration and iridescence; the male (pictured) has yellow wings and iridescence, while females have greenish-white wings and are not iridescent.
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.
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 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."
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.
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