Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, jellyfish, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior. Animals can be divided into species that undergo complete metamorphosis ("holometaboly"), incomplete metamorphosis ("hemimetaboly"), or no metamorphosis ("ametaboly").
Odonata is an order of predatory flying insects that includes the dragonflies and damselflies. The two groups are distinguished with dragonflies usually being bulkier with large compound eyes together and wings spread up or out at rest, while damselflies are usually more slender with eyes placed apart and wings folded together along body at rest. Adult odonates can land and perch, but rarely walk.
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.
Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies but are usually smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. Damselflies have existed since the Late Jurassic, and are found on every continent except Antarctica.
Hemiptera is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of piercing-sucking mouthparts. The name "true bugs" is often limited to the suborder Heteroptera.
In biology, a nymph is the juvenile form of some invertebrates, particularly insects, which undergoes gradual metamorphosis (hemimetabolism) before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult, except for a lack of wings and the emergence of genitalia. In addition, while a nymph moults, it never enters a pupal stage. Instead, the final moult results in an adult insect. Nymphs undergo multiple stages of development called instars.
Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the most primitive groups of Neoptera, with close relatives identified from the Carboniferous and Lower Permian geological periods, while true stoneflies are known from fossils only a bit younger. Their modern diversity, however, apparently is of Mesozoic origin.
Mayflies are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies. Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families.
Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the same ways as other insects. Some diving insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete.
The Pterygota are a subclass of insects that includes all winged insects and the orders that are secondarily wingless.
The Exopterygota, also known as Hemimetabola, are a superorder of insects of the subclass Pterygota in the infraclass Neoptera, in which the young resemble adults but have externally developing wings. They undergo a modest change between immature and adult, without going through a pupal stage. The nymphs develop gradually into adults through a process of moulting.
The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embryology, bioinformatics and scientific computing. It is estimated that the class of insects originated on Earth about 480 million years ago, in the Ordovician, at about the same time terrestrial plants appeared. Insects are thought to have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. The oldest insect fossil has been proposed to be Rhyniognatha hirsti, estimated to be 400 million years old, but the insect identity of the fossil has been contested. Global climate conditions changed several times during the history of Earth, and along with it the diversity of insects. The Pterygotes underwent a major radiation in the Carboniferous while the Endopterygota underwent another major radiation in the Permian.
Insect physiology includes the physiology and biochemistry of insect organ systems.
Chloroperlidae are a family of stoneflies, commonly known as green stoneflies, with more than 200 species and 22 genera. They appear green to yellow in colour, and are popularly used among fisherman as bait for trout fishing. Green stoneflies live in the benthic zone of the cold streams and rivers of five continents and four zoogeographical regions, emerging from the water to live in the riparian zone as adults. They are sensitive to pollutants, making them an indicator species for determining the quality of water bodies. Chloroperlidae are hemimetabolous, having no pupal stage, but instead hatch from eggs as nymphs and mature directly into adults. They are omnivorous, feeding on small organisms and plant particles, and become more carnivorous as they mature. The classification of Chloroperlidae is contested, with some believing that they should be considered as members of different orders, as opposed to the order Plecoptera that they currently belong to.
Odonata are insects with an incomplete metamorphosis (hemimetabolous). The aquatic larva or nymph hatches from an egg, and develops through eight to seventeen instars before leaving the water and emerging as the winged adult or imago.
Rhynocoris longifrons is a species of assassin bug in the family Reduviidae. It is a predator of other insects and is found in Asia. Crops on which it is found feeding on pests include pigeon pea, cardamom and peanuts. The insects are potentially useful in biological control because they are more resistant to pesticides than are the pests they consume.
Rhynocoris marginatus is a species of assassin bug in the family Reduviidae. It is a predator of other insects and is found in Asia. Crops in India on which it has been found feeding on pests include sugarcane, pigeon pea, cardamom, cotton, tea, and peanuts. The insects are potentially useful in biological control because they are more resistant to pesticides than are the pests on which they feed.
Aquatic macroinvertebrates are insects in their nymph and larval stages, snails, worms, crayfish, and clams that spend at least part of their lives in water. These insects play a large role in freshwater ecosystems by recycling nutrients as well as providing food to higher trophic levels.
Stenoperla prasina is a species of stonefly belonging to the family Eustheniidae. This species is endemic to New Zealand and is classified as "Not Threatened" under the New Zealand Threat Classification System. It is found on the North, South and Stewart Island / Rakiura Islands as well as on Little Barrier Island. Although adults of this species are most often coloured bright green, this species can be coloured yellow. This species inhabits clean, cold, running streams and rivers with stony bottoms within native bush. It is a known indicator of water quality. The larvae eat plant detritus and other aquatic insects while the adult insects feed on sooty mould fungi as well as other plant matter. The adults of this species are a known food source for New Zealand long tailed bats. Adults have been dissected and have been found to have been carrying Nematomorpha and trematode parasites. The New Zealand Department of Conservation classifies this species as "Not Threatened". In 2022 a specimen of this species was the 5 millionth specimen to be digitised in the Natural History Museum, London collection.
