Angustidontus is a genus of predatory pelagic crustaceans from the Late Devonian and Early Carboniferous periods, classified as part of the subclass Eumalacostraca. Fossils of the genus have been recovered in relative abundance from Canada, Germany, the Czech Republic, Poland, Belarus, Ukraine and large parts of the United States, including Oklahoma, Ohio, Indiana, Kentucky, Montana, Utah, Nevada.

The major eumalacostracan lineages had already diverged from each other during the Devonian, but their early evolutionary history remains relatively unknown due to a poor fossil record, making fossils of Angustidontus and other early eumalacostracans important for scientific study. Historically of uncertain classification, studies on the paleobiology of Angustidontus have allowed researchers to place it between the eumalacostracan orders Amphionidacea and Decapoda. (Full article...)

A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threatens dragonfly populations around the world. Adult dragonflies are characterised by a pair of large, multifaceted, compound eyes, two pairs of strong, transparent wings, sometimes with coloured patches, and an elongated body. Many dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. An adult dragonfly's compound eyes have nearly 24,000 ommatidia each.

Dragonflies can be mistaken for the closely related damselflies, which make up the other odonatan infraorder (Zygoptera) and are similar in body plan, though usually lighter in build; however, the wings of most dragonflies are held flat and away from the body, while damselflies hold their wings folded at rest, along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Dragonflies make use of motion camouflage when attacking prey or rivals.

Dragonflies are predatory insects, both in their aquatic nymphal stage (also known as "naiads") and as adults. In some species, the nymphal stage lasts up to five years, and the adult stage may be as long as 10 weeks, but most species have an adult lifespan in the order of five weeks or less, and some survive for only a few days. They are fast, agile fliers capable of highly accurate aerial ambush, sometimes migrating across oceans, and often live near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilisation, and sperm competition. During mating, the male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male's secondary genitalia at the front of his abdomen, forming the "heart" or "wheel" posture. (Full article...)

The order Embioptera, commonly known as webspinners or footspinners, are a small group of mostly tropical and subtropical insects, classified under the subclass Pterygota. 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 find 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...)

Eusarcana (meaning "true flesh") is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Eusarcana have been discovered in deposits ranging in age from the Early Silurian to the Early Devonian. Classified as part of the family Carcinosomatidae, the genus contains three species, E. acrocephalus, E. obesus and E. scorpionis, from the Silurian-Devonian of Scotland, the Czech Republic and the United States respectively.

Eusarcana is known for its odd proportions and features; the broad abdomen, thin and long tail, spined and forward-facing walking appendages and sharp and curved tail spike differentiate it from most other eurypterids, but are shared with other carcinosomatid eurypterids. The triangular carapace, oddly positioned forward-facing eyes differentiate the genus further from its closest relatives. At 80 centimetres (31.5 in) in length, E. scorpionis represents a moderately large species of eurypterid, and far exceeded other representatives of the genus in size, such as the 4 cm (1.5 in) long E. obesus.

Originally described under the name Eusarcus, this name was preoccupied by a genus of living harvestmen in the family Gonyleptidae. Following the discovery of this homonym, the genus was also wrongly recognized as synonymous with the related Carcinosoma and was only given replacement names for the older name decades after the error was discovered, first as Eusarcana in 1942 and later as Paracarcinosoma (assumed to have been named without knowledge of the earlier replacement name) in 1964. (Full article...)

Holmipterus is a problematic genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Holmipterus, H. suecicus, is known from deposits of Middle Silurian age in the Sweden. The generic name honours Gerhard Holm [sv], a renowned Swedish palaeontologist specialising in arthropods and crustaceans, and the species name suecicus is Latin for 'Swedish'.

Although Holmipterus was a large eurypterid and is known from multiple, albeit partial and fragmentary, specimens, it has proven difficult to determine where it fits in the eurypterid family tree. This is due to the fossil material referred to Holmipterus combining traits seen in different eurypterid groups, such as the Carcinosomatidae and Megalograptidae, and has some distinctive features, such as a telson (the posteriormost division of the body) with two articulating 'cercal blades', forming an organ capable of grasping. Though often classified either as a carcinosomatid or megalograptid, Holmipterus has also been classified as a genus of uncertain affinity within the Eurypterina suborder, or within the entire Eurypterida order. It is possible that the original 1979 description of Holmipterus suecicus reconstructed the telson inaccurately, and/or mistakenly combined fossil material actually belonging to two different genera. (Full article...)

Theridion grallator, also known as the Hawaiian happy-face spider, is a spider in the family Theridiidae that resides on the Hawaiian Islands. T. grallator gets its vernacular name of "Hawaiian happy-face spider" from the unique patterns superimposed on its abdomen, specifically those that resemble a smiley face. T. grallator is particularly notable because of its wide range of polymorphisms that may be studied to allow a better understanding of evolutionary mechanisms. In addition to the variety of color polymorphisms present, T. grallator demonstrates the interesting quality of diet-induced color change, in which its appearance temporarily changes as it metabolizes various food items. (Full article...)

Myrmecia regularis is a species of ant endemic to Australia. A member of the genus Myrmecia in the subfamily Myrmeciinae, it was first described by American entomologist Walter Cecil Crawley in 1925. These ants are medium to large in size, measuring 10 to 20 millimetres (0.4 to 0.8 in), and they are bright brownish-red in colour. Queens and workers share similar morphological features, but they can be distinguished by the noticeable size difference. Males also look similar, but collected specimens are too damaged to be examined properly.

Myrmecia regularis is found in the south-western coastal regions, inhabiting eucalypt woodland and open forests. They nest underground and do not build mounds. Workers are active during the day and night, foraging on trees in search for prey and sweet substances such as sap and nectar. The larvae are strictly carnivorous and only eat insects that workers capture. Nuptial flight occurs around February to April, with queens shedding their wings inside the nest and mating near to their parent nest. Queens tend to look for food for their young before they hatch, taking as long as eight months to develop. Certain frog species are known to dwell inside M. regularis colonies. (Full article...)

Myrmeciites is an extinct form genus of bulldog ants in the subfamily Myrmeciinae of the family Formicidae, which contains three described species and two fossils not placed beyond the genus level. Described in 2006 from Ypresian stage (Early Eocene) deposits, all three of the described species and one unplaced fossil are from British Columbia, Canada, while the second unplaced fossil is from Washington State, USA. These ants were large, with the largest specimens collected reaching 3 centimetres (1.2 in). The behaviour of these ants would have been similar to extant Myrmeciinae ants, such as solitary foraging, nesting either in the soil or trees, and leaving no pheromone trail to food sources. Due to the poor preservation of these ants, their phylogenetic position among Myrmeciinae is unclear, and no type species has been designated. These ants are classified as incertae sedis in Myrmeciinae, but some writers have classified it as incertae sedis within the insect order Hymenoptera. This reclassification, however, has not been accepted; instead, Myrmeciites remains in Myrmeciinae. (Full article...)

Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are currently considered a clade, called Anthophila. There are over 20,000 known species of bees in seven recognized biological families. Some species – including honey bees, bumblebees, and stingless bees – live socially in colonies while most species (>90%) – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary.

Bees are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, but they are small and often mistaken for wasps or flies. Bees range in size from tiny stingless bee species, whose workers are less than 2 millimeters (0.08 in) long, to the leafcutter bee Megachile pluto, the largest species of bee, whose females can attain a length of 39 millimeters (1.54 in).

Bees feed on nectar and pollen, the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for their larvae. Vertebrate predators of bees include primates and birds such as bee-eaters; insect predators include beewolves and dragonflies. (Full article...)

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...)

Chirocephalus diaphanus is a widely distributed European species of fairy shrimp that lives as far north as Great Britain, where it is the only surviving species of fairy shrimp and is protected under the Wildlife and Countryside Act 1981. It is a translucent animal, about 0.5 in (13 mm) long, with reddened tips to the abdomen and appendages. The body comprises a head, a thorax bearing 11 pairs of appendages, and a seven-segmented abdomen. In males, the antennae are enlarged to form "frontal appendages", while females have an egg pouch at the end of the thorax.

The life cycle of C. diaphanus is extremely fast, and the species can only persist in pools without predators. The eggs tolerate drying out, and hatch when re-immersed in water. C. diaphanus was first reported in the scientific literature in 1704, but was only separated from other species and given its scientific name in 1803. The specific epithet diaphanus refers to the animal's transparency. (Full article...)

Unionopterus is a genus of eurypterid, an extinct group of aquatic arthropods commonly known as "sea scorpions". Fossils have been registered from the Early Carboniferous period. The genus contains only one species, U. anastasiae, recovered from deposits of Tournaisian to Viséan stages in Kazakhstan. Known from one single specimen (now presumed to be lost) which was described in a publication of Russian language with poor illustrations, Unionopterus' affinities are extremely poorly known.

Unionopterus was described in 1948 after the discovery of its only known specimen in the Karaganda Formation of Kazakhstan (at that time part of the Soviet Union). This was one of the first discoveries of eurypterids in the Soviet Union and Carboniferous eurypterids in general. It was probably a swimming organism as well as other eurypterids, although not as good as its relatives.

There are numerous factors that have made Unionopterus a problematic genus for eurypterid researchers. It has been placed in the family Adelophthalmidae and it has even been speculated that a species of Adelophthalmus, A. dumonti, actually belongs to Unionopterus, but this cannot be confirmed. Many authors have chosen to completely ignore the genus during phylogenetic studies, making Unionopterus an enigmatic eurypterid. (Full article...)

Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.

Ants form colonies that range in size from a few dozen individuals often living in small natural cavities to highly organised colonies that may occupy large territories with sizeable nest that consist of millions of individuals or into the hundreds of millions in super colonies. Typical colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.

Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in moist tropical ecosystems and may exceed the combined biomass of wild birds and mammals. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships. (Full article...)

Pruemopterus is a genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Pruemopterus, P. salgadoi, is known only from a single fossil specimen discovered in geological deposits of Early Devonian age in Germany. The name of the genus is derived from the Prüm river and the surrounding Prüm valley, which contains the finding place of the fossil, and the Ancient Greek πτερόν (pteron, "wing"), referring to the eurypterid swimming paddles, and the species name honors the Brazilian photographer and photojournalist Sebastião Salgado.

Pruemopterus was a very small adelophthalmid eurypterid, with the only known specimen measuring about 2.5 centimeters (0.98 in) in length. Although superficially similar to the related genus Parahughmilleria, Pruemopterus can be distinguished from other adelophthalmids by several features, most notably its wide and vaguely rectangular carapace (head plate) and its rounded, rather than elongated, eyes. Pruemopterus lived alongside other Early Devonian animals, including several other eurypterid genera, in a shallow brackish to fresh water environment. (Full article...)

Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.

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...)