Evolution has produced enormous variety in insects. Pictured are some possible shapes of antennae.
Larva of the Papilio xuthus butterfly
A pie chart of described eukaryote species, showing just over half of these to be insects
Eurosta solidaginis Goldenrod Gall Fly larva
Insects with population trends documented by the International Union for Conservation of Nature, for orders Collembola, Hymenoptera, Lepidoptera, Odonata, and Orthoptera. Of 203 insect species that had such documented population trends in 2013, 33% were in decline.
The larvae of the Hercules beetle (Dynastes hercules) are among the largest of any species of insect
Stylized diagram of insect digestive tract showing malpighian tubule, from an insect of the order Orthoptera
Campodeiform larva of Micromus sp.
Bumblebee defecating. Note the contraction of the abdomen to provide internal pressure
The tube-like heart (green) of the mosquito Anopheles gambiae extends horizontally across the body, interlinked with the diamond-shaped wing muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.
The different forms of the male (top) and female (bottom) tussock moth Orgyia recens is an example of sexual dimorphism in insects.
Gulf fritillary life cycle, an example of holometabolism.
Most insects have compound eyes and two antennae.
A cathedral mound created by termites (Isoptera).
White-lined sphinx moth feeding in flight
The backswimmer Notonecta glauca underwater, showing its paddle-like hindleg adaptation
Perhaps one of the most well-known examples of mimicry, the viceroy butterfly (top) appears very similar to the monarch butterfly (bottom).
European honey bee carrying pollen in a pollen basket back to the hive
Aedes aegypti, a parasite, is the vector of dengue fever and yellow fever
Because they help flowering plants to cross-pollinate, some insects are critical to agriculture. This European honey bee is gathering nectar while pollen collects on its body.
A robberfly with its prey, a hoverfly. Insectivorous relationships such as these help control insect populations.
The common fruit fly Drosophila melanogaster is one of the most widely used organisms in biological research.

Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.

- Larva

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.

- Insect
Evolution has produced enormous variety in insects. Pictured are some possible shapes of antennae.

2 related topics

Alpha

A dragonfly in its final moult, undergoing metamorphosis from its nymph form to an adult

Metamorphosis

Biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation.

Biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation.

A dragonfly in its final moult, undergoing metamorphosis from its nymph form to an adult
Incomplete metamorphosis in the grasshopper with different instar nymphs. The largest specimen is adult.
Two types of metamorphosis are shown. In a complete (holometabolous) metamorphosis the insect passes through four distinct phases, which produce an adult that does not resemble the larva. In an incomplete (hemimetabolous) metamorphosis an insect does not go through a full transformation, but instead transitions from a nymph to an adult by molting its exoskeleton as it grows.
Metamorphosis of butterfly (PSF)
Just before metamorphosis, only 24 hours are needed to reach the stage in the next picture.
Almost functional common frog with some remains of the gill sac and a not fully developed jaw
The large external gills of the crested newt
larva
pupa
pupa ready to hatch
adult

Some insects, fish, amphibians, mollusks, crustaceans, cnidarians, echinoderms, and tunicates undergo metamorphosis, which is often accompanied by a change of nutrition source or behavior.

Generally organisms with a larva stage undergo metamorphosis, and during metamorphosis the organism loses larval characteristics.

Butterfly

Possibly the original butter-fly. A male brimstone (Gonepteryx rhamni) in flight
Prodryas persephone, a Late Eocene butterfly from the Florissant Fossil Beds, 1887 engraving
Lithopsyche antiqua, an Early Oligocene butterfly from the Bembridge Marls, Isle of Wight, 1889 engraving
The wings of butterflies, here Aglais io, are covered with coloured scales.
Butterfly antennal shapes, mainly clubbed, unlike those of moths. Drawn by C. T. Bingham, 1905
Unlike butterflies, most moths (like Laothoe populi) fly by night and hide by day.
Monarch migration route
Overwintering monarchs cluster on oyamel trees near Angangueo, Mexico.
Life cycle of the monarch butterfly
Mating pair of spotted fritillaries on greater pignut
The male small skipper (Thymelicus sylvestris) has pheromone-releasing "sex brands" (dark line) on the upperside of its forewings.
Eggs of black-veined white (Aporia crataegi) on apple leaf
A butterfly laying eggs underneath the leaf
Aposematic caterpillar of Papilio machaon, in threat pose
Mutualism: ant tending a lycaenid caterpillar, Catapaecilma major
Cryptic countershaded caterpillar of a hawkmoth, Ceratomia amyntor
Chrysalis of gulf fritillary
An adult Parthenos sylvia butterfly
An Australian painted lady feeding on a flowering shrub
Heteronympha merope taking off
Braconid parasitoidal wasp (Apanteles species) cocoons attached to lime butterfly (Papilio demoleus) caterpillar
Heliconius warns off predators with Müllerian mimicry.
Giant swallowtail caterpillar everting its osmeterium in defence; it is also mimetic, resembling a bird dropping.
Eyespots of speckled wood (Pararge aegeria) distract predators from attacking the head. This insect can still fly with a damaged left hindwing.
Ancient Egyptian relief sculpture, 26th dynasty, Thebes. c. 664–525 BC
Butterfly and Chinese wisteria, by Xü Xi. Early Song Dynasty, c. 970
A butterfly in the coat of arms of Perho
Alice meets the caterpillar. Illustration by Sir John Tenniel in Lewis Carroll's Alice in Wonderland, c. 1865
Der Schmetterlingsjäger (The butterfly hunter) painting by Carl Spitzweg, 1840
A serving tray decorated with butterfly wings
Nō robe Japan 1700s. Silk embroidered with silk thread and stenciled with gold foil

Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths.

Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed.