Insect

Insects or Insecta (from Latin insectum) are hexapod invertebrates and the largest group within the arthropod phylum.

Familiar examples of invertebrates include arthropods (insects, arachnids, crustaceans, and myriapods), mollusks (chitons, snails, bivalves, squids, and octopuses), annelids (earthworms and leeches), and cnidarians (hydras, jellyfishes, sea anemones, and corals).

The immature stages often differ from the adults in structure, habit and habitat, and can include a passive pupal stage in those groups that undergo four-stage metamorphosis.

A pupa (pūpa, "doll"; plural: pūpae) is the life stage of some insects undergoing transformation between immature and mature stages.

Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

Examples of animals with exoskeletons include insects such as grasshoppers and cockroaches, and crustaceans such as crabs and lobsters, as well as the shells of certain sponges and the various groups of shelled molluscs, including those of snails, clams, tusk shells, chitons and nautilus.

Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies.

Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera.

Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies.

Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea.

Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males.

Crickets (also known as "true crickets"), of the family Gryllidae, are insects related to bush crickets, and, more distantly, to grasshoppers.

Insects or Insecta (from Latin insectum) are hexapod invertebrates and the largest group within the arthropod phylum.

The subphylum Hexapoda (from the Greek for six legs) constitutes the largest number of species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered insects).

The most diverse insect groups appear to have coevolved with flowering plants.

Charles Darwin mentioned evolutionary interactions between flowering plants and insects in On the Origin of Species (1859).

Humans regard certain insects as pests, and attempt to control them using insecticides, and a host of other techniques.

Insecticides are substances used to kill insects.

Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

The thorax is the midsection (tagma) of the insect body.

Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

It is a primary component of cell walls in fungi, the exoskeletons of arthropods, such as crustaceans and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians.

Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males.

This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders.

Many insects spend at least part of their lives under water, with larval adaptations that include gills, and some adult insects are aquatic and have adaptations for swimming.

With the exception of some aquatic insects, the filaments and lamellae (folds) contain blood or coelomic fluid, from which gases are exchanged through the thin walls.

Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

A compound eye is a visual organ found in arthropods such as insects and crustaceans.

Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

The legs of insects and myriapods are uniramous.

Human activities also have effects on insect biodiversity.

Insect biodiversity accounts for a large proportion of all biodiversity on the planet—over half of the estimated 1.5 million organism species described are classified as insects.

The immature stages often differ from the adults in structure, habit and habitat, and can include a passive pupal stage in those groups that undergo four-stage metamorphosis.

The first stage of the insect life cycle is the egg, or embryo, for all developmental strategies.

Traditionally, insects defined in this way were divided into "Apterygota" (the first five groups in the table)—the wingless insects—and Pterygota—the winged insects.

The Pterygota are a subclass of insects that includes the winged insects.

For the purposes of this article, the middle definition is used; insects consist of two wingless taxa, Archaeognatha (jumping bristletails) and Zygentoma (silverfish), plus the winged or secondarily wingless Pterygota.

Zygentoma are an order in the class Insecta, and consist of about 400 known species.

The name Apterygota is sometimes applied to a subclass of small, agile insects, distinguished from other insects by their lack of wings in the present and in their evolutionary history; notable examples are the silverfish, the firebrat, and the jumping bristletails.

Four super radiations of insects have occurred: beetles (evolved about 300 million years ago), flies (evolved about 250 million years ago), and moths and wasps (evolved about 150 million years ago).

A wasp is any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant.

It may have superficially resembled a modern-day silverfish insect.

A silverfish (Lepisma saccharina) is a small, wingless insect in the order Zygentoma (formerly Thysanura).

The origins of insect flight remain obscure, since the earliest winged insects currently known appear to have been capable fliers.

Insects are the only group of invertebrates that have evolved wings and flight.

The flies and moths along with the fleas evolved from the Mecoptera.

Mecoptera (from the Greek: mecos = "long", ptera = "wings") are an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide.

Humans regard certain insects as pests, and attempt to control them using insecticides, and a host of other techniques.

The animal groups of greatest importance as pests (in order of economic importance) are insects, mites, nematodes and gastropods.