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...)
Hibbertopterus was the largest eurypterid within the stylonurine suborder, with the largest fossil specimens suggesting that H. scouleri could reach lengths around 180–200 centimetres (5.9–6.6 ft). Though this is significantly smaller than the largest eurypterid overall, Jaekelopterus, which could reach lengths of around 250 centimetres (8.2 ft), Hibbertopterus is likely to have been the heaviest due to its broad and compact body. Furthermore, trackway evidence indicates that the South African species H. wittebergensis might have reached lengths similar to Jaekelopterus.
Like many other stylonurine eurypterids, Hibbertopterus fed through a method called sweep-feeding. It used its specialised forward-facing appendages (limbs), equipped with several spines, to rake through the substrate of the environments in which it lived in search for small invertebrates to eat, which it could then push towards its mouth. Though long hypothesised, the fact that eurypterids were capable of terrestrial locomotion was definitely proven through the discovery of a fossil trackway made by Hibbertopterus in Scotland. The trackway showed that an animal measuring around 160 centimetres (5.2 ft) had slowly lumbered across a stretch of land, dragging its telson (the posteriormost division of its body) across the ground after it. How Hibbertopterus could survive on land, however briefly, is unknown but it might have been possible through either its gills being able to function in air as long as they were wet or by the animal possessing a dual respiratory system, theorised to have been present in at least some eurypterids. (Full article...)
Chelicerata split from Mandibulata by the mid-Cambrian, as evidenced by stem-group chelicerates like Habeliida and Mollisonia present by this time. The surviving marine species include the four species of xiphosurans (horseshoe crabs), and possibly the 1,300 species of pycnogonids (sea spiders), if the latter are indeed chelicerates. On the other hand, there are over 77,000 well-identified species of air-breathing chelicerates, and there may be about 500,000 unidentified species.
Like all arthropods, chelicerates have segmented bodies with jointed limbs, all covered in a cuticle made of chitin and proteins. The chelicerate body plan consists of two tagmata, the prosoma and the opisthosoma, except that mites have lost a visible division between these sections. The chelicerae, which give the group its name, are the only appendages that appear before the mouth. In most sub-groups, they are modest pincers used to feed. However, spiders' chelicerae form fangs that most species use to inject venom into prey. The group has the open circulatory system typical of arthropods, in which a tube-like heart pumps blood through the hemocoel, which is the major body cavity. Marine chelicerates have gills, while the air-breathing forms generally have both book lungs and tracheae. In general, the ganglia of living chelicerates' central nervous systems fuse into large masses in the cephalothorax, but there are wide variations and this fusion is very limited in the Mesothelae, which are regarded as the oldest and most basal group of spiders. Most chelicerates rely on modified bristles for touch and for information about vibrations, air currents, and chemical changes in their environment. The most active hunting spiders also have very acute eyesight. (Full article...)
Flea, the common name for the orderSiphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about 3 millimetres (1⁄8 inch) long, are usually brown, and have bodies that are "flattened" sideways or narrow, enabling them to move through their hosts' fur or feathers. They lack wings; their hind legs are extremely well adapted for jumping. Their claws keep them from being dislodged, and their mouthparts are adapted for piercing skin and sucking blood. They can leap 50 times their body length, a feat second only to jumps made by another group of insects, the superfamily of froghoppers. Flea larvae are worm-like, with no limbs; they have chewing mouthparts and feed on organic debris left on their hosts' skin.
Genetic evidence indicates that fleas are a specialised lineage of parasitic scorpionflies (Mecoptera) sensu lato, most closely related to the family Nannochoristidae. The earliest known fleas lived in the Middle Jurassic; modern-looking forms appeared in the Cenozoic. Fleas probably originated on mammals first and expanded their reach to birds. Each species of flea specializes, more or less, on one species of host: many species of flea never breed on any other host; some are less selective. Some families of fleas are exclusive to a single host group; for example, the Malacopsyllidae are found only on armadillos, the Ischnopsyllidae only on bats, and the Chimaeropsyllidae only on elephant shrews.
Ant mimicry or myrmecomorphy is mimicry of ants by other organisms; it has evolved over 70 times. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive. Some arthropods mimic ants to escape predation (Batesian mimicry), while some predators of ants, especially spiders, mimic them anatomically and behaviourally in aggressive mimicry. Ant mimicry has existed almost as long as ants themselves; the earliest ant mimics in the fossil record appear in the mid-Cretaceous alongside the earliest ants.
In myrmecophily, mimic and model live commensally together; in the case of ants, the mimic is an inquiline in the ants' nest. Such mimics may in addition be Batesian or aggressive mimics. To overcome ants' powerful defences, mimics may imitate ants chemically with ant-like pheromones, visually, or by imitating an ant's surface microstructure to defeat the ants' tactile inspections. (Full article...)
Afraflacilla braunsi is a species of jumping spider in the genusAfraflacilla. First found in South Africa, the spider was subsequently observed living in Saudi Arabia, Turkmenistan, the United Arab Emirates and Yemen, although it is likely to have a wider distribution. First described in 1903 by George and Elizabeth Peckham, it was originally allocated to the genus Pseudicius with the name Pseudicius braunsii. After being renamed Icius braunsi in 1987, it was finally given its current name by Jerzy Prószyński in 2017. Pseudicius tripunctatus, now called Afraflacilla tripunctatus, is a synonym.
A small to medium-sized spider, Afraflacilla braunsi has a carapace that is between 1.7 and 1.9 mm (0.07 and 0.07 in) long and an abdomen 2.2 and 3.2 mm (0.09 and 0.13 in) long. The carapace is brown, sometimes with yellow sides. The abdomen is light brown or fawn with lighter yellow patches. It has large brown front legs, the remainder generally yellow and less robust. It makes noises by rubbing its forelegs against small hairs under its eyes. The copulatory organs are distinctive for the species. The male has a characteristically bulbous palpal bulb and a single long projection, or apophysis, extending from the palpal tibia. The female has very long and coiled insemination ducts that lead to large spermathecae. (Full article...)
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The external morphology of Lepidoptera is the physiological structure of the bodies of insects belonging to the order Lepidoptera, also known as butterflies and moths. Lepidoptera are distinguished from other orders by the presence of scales on the external parts of the body and appendages, especially the wings. Butterflies and moths vary in size from microlepidoptera only a few millimetres long, to a wingspan of many inches such as the Atlas moth. Comprising over 160,000 described species, the Lepidoptera possess variations of the basic body structure which has evolved to gain advantages in adaptation and distribution.
Lepidopterans undergo complete metamorphosis, going through a four-stage life cycle: egg, larva or caterpillar, pupa or chrysalis, and imago (plural: imagines) / adult. The larvae – caterpillars – have a toughened (sclerotised) head capsule, chewing mouthparts, and a soft body, that may have hair-like or other projections, three pairs of true legs, and up to five pairs of prolegs. Most caterpillars are herbivores, but a few are carnivores (some eat ants, aphids, or other caterpillars) or detritivores. Larvae are the feeding and growing stages and periodically undergo hormone-induced ecdysis, developing further with each instar, until they undergo the final larval–pupal moult. The larvae of many lepidopteran species will either make a spun casing of silk called a cocoon and pupate inside it, or will pupate in a cell under the ground. In many butterflies, the pupa is suspended from a cremaster and is called a chrysalis.
The adult body has a hardened exoskeleton, except for the abdomen which is less sclerotised. The head is shaped like a capsule with appendages arising from it. Adult mouthparts include a prominent proboscis formed from maxillary galeae, and are adapted for sucking nectar. Some species do not feed as adults, and may have reduced mouthparts, while others have them modified for piercing and suck blood or fruit juices. Mandibles are absent in all except the Micropterigidae which have chewing mouthparts. Adult Lepidoptera have two immobile, multi-faceted compound eyes, and only two simple eyes or ocelli, which may be reduced. The three segments of the thorax are fused together. Antennae are prominent and besides the faculty of smell, also aid navigation, orientation, and balance during flight. In moths, males frequently have more feathery antennae than females, for detecting the female pheromones at a distance. There are two pairs of membranouswings which arise from the mesothoracic (middle) and metathoracic (third) segments; they are usually completely covered by minute scales. The two wings on each side act as one by virtue of wing-locking mechanisms. In some groups, the females are flightless and have reduced wings. The abdomen has ten segments connected with movable inter-segmental membranes. The last segments of the abdomen form the external genitalia. The genitalia are complex and provide the basis for family identification and species discrimination. (Full article...)
Eusociality (Greek εὖ eu "good" and social) is the highest level of organization of sociality. It is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups. The division of labor creates specialized behavioral groups within an animal society which are sometimes referred to as 'castes'. Eusociality is distinguished from all other social systems because individuals of at least one caste usually lose the ability to perform behaviors characteristic of individuals in another caste. Eusocial colonies can be viewed as superorganisms.
Eusociality has evolved among the insects, crustaceans, and mammals. It is most widespread in the Hymenoptera (ants, bees, and wasps) and in Blattodea (termites). A colony has caste differences: queens and reproductivemales take the roles of the sole reproducers, while soldiers and workers work together to create and maintain a living situation favorable for the brood. Queens produce multiple queen pheromones to create and maintain the eusocial state in their colonies; they may also eat eggs laid by other females or exert dominance by fighting. There are two eusocial rodents: the naked mole-rat and the Damaraland mole-rat. Some shrimps, such as Synalpheus regalis, are eusocial. E. O. Wilson and others have made the claim that humans have evolved a weak form of eusociality. It has been suggested that the colonial and epiphytic staghorn fern, too, may make use of a primitively eusocial division of labor. (Full article...)
Spiders (orderAraneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except Antarctica, and have become established in nearly every land habitat. , 51,673 spider species in 136 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900.
Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel. However, as there is currently neither paleontological nor embryological evidence that spiders ever had a separate thorax-like division, there exists an argument against the validity of the term cephalothorax, which means fused cephalon (head) and the thorax. Similarly, arguments can be formed against the use of the term "abdomen", as the opisthosoma of all spiders contains a heart and respiratory organs, organs atypical of an abdomen.
Unlike insects, spiders do not have antennae. In all except the most primitive group, the Mesothelae, spiders have the most centralized nervous systems of all arthropods, as all their ganglia are fused into one mass in the cephalothorax. Unlike most arthropods, spiders have no extensor muscles in their limbs and instead extend them by hydraulic pressure. (Full article...)
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Zigrasimecia hoelldobleri worker
Zigrasimecia is an extinct genus of ants which existed in the Cretaceous period approximately 98 million years ago. The first specimens were collected from Burmese amber in Kachin State, 100 kilometres (62 mi) west of Myitkyina town in Myanmar. In 2013, palaeoentomologists Phillip Barden and David Grimaldi published a paper describing and naming Zigrasimecia tonsora. They described a dealate female with unusual features, notably the highly specialized mandibles. Other features include large ocelli, short scapes, 12 antennomeres, small eyes, and a clypeal margin that has a row of peg-like denticles. The genus Zigrasimecia was originally incertae sedis (uncertain placement) within Formicidae until a second species, Zigrasimecia ferox, was described in 2014, leading to its placement in the subfamily Sphecomyrminae. Later, it was considered to belong to the distinct subfamily Zigrasimeciinae.
Due to the highly specialized mandibles, scientists believe that the ants exhibited habits no longer seen in extant ants. The highly movable head suggests that mobility was an important factor for them (probably for feeding behavior), and the rugose projections may have played a major role in nest excavation because the mandibles would have prevented such activity. Zigrasimecia most likely interacted with the extinct ant genus Gerontoformica through conflict and probably shared some of their ecological niches. The mandibles of these ants were probably used for mechanical interactions with food, and they may also have served as traps for potential arthropod prey such as mites and small flies. Zigrasimecia was possibly a generalist predator. (Full article...)
Nanahughmilleria is classified in the family Adelophthalmidae, the only clade in the superfamily Adelophthalmoidea. This clade was characterised by their small size, their parabolic (approximately U-shaped) carapaces and the presence of epimera (lateral "extensions" of the segment) on the seventh segment, among others. Nanahughmilleria was different from its relatives by the presence of more spines in its appendages (limbs) and by its genital morphology. The largest species confidently assigned to the genus was N. norvegica at 10 cm (3.9 in), making it a comparatively small eurypterid. (Full article...)
Butterflies are winged insects from the lepidopteransuborderRhopalocera, characterized by large, often brightly coloured wings that often fold together when at rest, and a conspicuous, fluttering flight. The group comprises the superfamiliesHedyloidea (moth-butterflies in the Americas) and Papilionoidea (all others). The oldest butterfly fossils have been dated to the Paleocene, about 56 million years ago, though they likely originated in the Late Cretaceous, about 101 million years ago.
Butterflies have a four-stage life cycle, and like other holometabolous insects they undergo complete metamorphosis. Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed, pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out, expands its wings to dry, and flies off.
Some butterflies, especially in the tropics, have several generations in a year, while others have a single generation, and a few in cold locations may take several years to pass through their entire life cycle. (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...)
Ticks are parasitic arachnids of the order Ixodida. They are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. The timing of the origin of ticks is uncertain, though the oldest known tick fossils are from the Cretaceous period, around 100 million years old. Ticks are widely distributed around the world, especially in warm, humid climates.
Ticks belong to two major families, the Ixodidae or hard ticks, and the Argasidae, or soft ticks. Nuttalliella, a genus of tick from southern Africa, is the only member of the family Nuttalliellidae, and represents the most primitive living lineage of ticks. Adults have ovoid/pear-shaped bodies (idiosomas) which become engorged with blood when they feed, and eight legs. Their cephalothorax and abdomen are completely fused. In addition to having a hard shield on their dorsal surfaces, known as the scutum, hard ticks have a beak-like structure at the front containing the mouthparts, whereas soft ticks have their mouthparts on the underside of their bodies. Ticks locate potential hosts by sensing odor, body heat, moisture, and/or vibrations in the environment.
Ticks have four stages to their life cycle, namely egg, larva, nymph, and adult. Ticks belonging to the Ixodidae family undergo either a one-host, two-host, or three-host life cycle. Argasid ticks have up to seven nymphal stages (instars), each one requiring blood ingestion, and as such, Argasid ticks undergo a multihost life cycle. Because of their hematophagous (blood-ingesting) diets, ticks act as vectors of many serious diseases that affect humans and other animals. (Full article...)
Chamberlin was a prolific taxonomist who named over 4,000 new animal species in over 400 scientific publications. He specialized in arachnids (spiders, scorpions, and relatives) and myriapods (centipedes, millipedes, and relatives), ranking among the most prolific arachnologists and myriapodologists in history. He described over 1,400 species of spiders, 1,000 species of millipedes, and the majority of North American centipedes, although the quantity of his output was not always matched with quality, leaving a mixed legacy to his successors. He also did pioneering ethnobiological studies with the Goshute and other indigenous people of the Great Basin, cataloging indigenous names and cultural uses of plants and animals. Chamberlin was celebrated by his colleagues at the University of Utah, however he was disliked among some arachnologists, including some of his former students. After retirement he continued to write, publishing on the history of education in his home state, especially that of the University of Utah.
Chamberlin was a member of the Church of Jesus Christ of Latter-day Saints (LDS Church). In the early twentieth century, Chamberlin was among a quartet of popular Mormon professors at Brigham Young University whose teaching of evolution and biblical criticism resulted in a 1911 controversy among University and Church officials, eventually resulting in the resignation of him and two other professors despite widespread support from the student body, an event described as Mormonism's "first brush with modernism". (Full article...)
... that the family placement for the fossil moth genus Dominickus was not noticed until entomologistNorman Tindale was looking at pictures of modern moths from Australia?
The following are images from various arthropod-related articles on Wikipedia.
Image 1Ghost 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 3This 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 6Some 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 7Crab larva barely recognisable as a crab, radically changes its form when it undergoes ecdysis as it matures (from Arthropod exoskeleton)
Image 8 Honeybee larvae have flexible but delicate unsclerotised cuticles. (from Arthropod exoskeleton)
Image 13In 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 19Mature 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 20Reconstruction of Mollisonia plenovenatrix, the oldest known arthropod with confirmed chelicerae (from Chelicerata)
Image 24 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 28Formation 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 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)
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.
Argiope trifasciata, the banded garden or banded orb-weaving spider, is a species of arachnid in the family Araneidae. It is native to North and South America but has spread to other parts of the world. This ventral view of a female A. trifasciata shows her in the centre of her web, which can reach a diameter of 60 cm (24 in). The function of the zig-zag web decorations is unclear, but they may serve to make the spider appear larger or to act as a warning sign.
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 European paper wasp (Polistes dominula or Polistes dominulus) is one of the most common species of wasps in the genus Polistes. Originally described in 1791 by German naturalist Johann Ludwig Christ as Vespa dominula, it is native to southern Europe and North Africa, as well as temperate parts of Asia as far east as China. It has also been introduced to Australia, New Zealand, South Africa and the Americas. The species is common and cosmopolitan due to its exceptional survival features, such as a productive colony cycle, a short development time and a higher ability to endure predator attacks. It generally lives in temperate, terrestrial habitats, such as chaparral, forest and grassland biomes.
This picture shows a young European paper wasp queen guarding her nest and eggs.
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 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.
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 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.
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 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.
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 Adonis blue (Polyommatus bellargus) is a butterfly in the family Lycaenidae, found in Europe and parts of West Asia. This photograph, taken in a chalk meadow at Yoesden Bank in Buckinghamshire, England, shows the underside of the folded wings of a male Adonis blue; the upper side is a bright, sky-blue.
Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics. Differences may include secondary sex characteristics, size, weight, color, or markings, as well as behavioral and cognitive differences. In the butterfly species Colias dimera (also known as the Dimera sulphur), seen here mating in Venezuela, the male on the right is a brighter shade of yellow than the female.
A macro shot of the head of a dragonfly, focusing on its compound eyes. Dragonfly eyes have up to 30,000 facets; each one is a separate light-sensing organ or ommatidium, arranged to give nearly a 360° field of vision.
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.
A honey bee extracts nectar from a flower using its proboscis. Tiny hairs covering the bee's body maintain a slight electrostatic charge, causing pollen from the flower's anthers to stick to the bee's hairs, allowing for pollination when the bee moves on to another flower.
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