Pupa

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Pupa of the rose chafer beetle, Cetonia aurata Cetoine global.jpg
Pupa of the rose chafer beetle, Cetonia aurata
Tumbler (pupa) of a mosquito. Unlike most pupae, tumblers can swim around actively. Mosquito Pupa.jpg
Tumbler (pupa) of a mosquito. Unlike most pupae, tumblers can swim around actively.

A pupa (Latin : pupa, "doll"; plural: pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages thereof being egg, larva, pupa, and imago. The processes of entering and completing the pupal stage are controlled by the insect's hormones, especially juvenile hormone, prothoracicotropic hormone, and ecdysone. The act of becoming a pupa is called pupation, and the act of emerging from the pupal case is called eclosion or emergence.

Contents

The pupae of different groups of insects have different names such as chrysalis for the pupae of butterflies and tumbler for those of the mosquito family. Pupae may further be enclosed in other structures such as cocoons, nests, or shells. [1]

Position in life cycle

The pupal stage follows the larval stage and precedes adulthood ( imago ) in insects with complete metamorphosis. The pupa is a non-feeding, usually sessile stage, or highly active as in mosquitoes. It is during the pupal stage that the adult structures of the insect are formed while the larval structures are broken down. The adult structures grow from imaginal discs. [2]

Duration

Pupal stage may last weeks, months, or even years, depending on temperature and the species of insect. [3] [4] For example, pupal stage lasts eight to fifteen days in monarch butterflies. [5] The pupa may enter dormancy or diapause until the appropriate season to emerge as an adult insect. In temperate climates pupae usually stay dormant during winter, while in the tropics pupae usually do so during the dry season.

Adult Hercus fontinalis emerging from cocoon Hercus fontinalis eclosion.jpg
Adult Hercus fontinalis emerging from cocoon
Eclosion of Papilio dardanus

Emergence

Insects emerge (eclose) from pupae by splitting the pupal case. Most butterflies emerge in the morning. In mosquitoes the emergence is in the evening or night. In fleas the process is triggered by vibrations that indicate the possible presence of a suitable host. Prior to emergence, the adult inside the pupal exoskeleton is termed pharate. Once the pharate adult has eclosed from the pupa, the empty pupal exoskeleton is called an exuvia ; in most hymenopterans (ants, bees and wasps) the exuvia is so thin and membranous that it becomes "crumpled" as it is shed.

Pupal mating

Mating in pierid Catopsilia pyranthe of male with newly emerged female. Mottled Emigrant (Catopsilia pyranthe) mating with emerging butterfly from pupa in Hyderabad, AP W IMG 9437.jpg
Mating in pierid Catopsilia pyranthe of male with newly emerged female.

In a few taxa of the Lepidoptera, especially Heliconius , pupal mating is an extreme form of reproductive strategy in which the adult male mates with a female pupa about to emerge, or with the newly moulted female; this is accompanied by other actions such as capping of the reproductive system of the female with the sphragis, denying access to other males, or by exuding an anti-aphrodisiac pheromone. [6] [7]

Defense

Pupae are usually immobile and are largely defenseless. To overcome this, pupae often are covered with a cocoon, conceal themselves in the environment, or form underground. [8] There are some species of Lycaenid butterflies which are protected in their pupal stage by ants. Another means of defense by pupae of other species is the capability of making sounds or vibrations to scare potential predators. A few species use chemical defenses including toxic secretions. The pupae of social hymenopterans are protected by adult members of the hive.

Types

Based on the presence or absence of articulated mandibles that are employed in emerging from a cocoon or pupal case, the pupae can be classified in to two types: [9] [10]

Based on whether the pupal appendages are free or attached to the body, the pupae can be classified in three types: [11]

Chrysalis

Common crow butterfly (Euploea core) chrysalis illustrating the Greek origin of the term: khrusos (chrysos) for gold Common crow pupa.jpg
Common crow butterfly ( Euploea core ) chrysalis illustrating the Greek origin of the term: χρυσός (chrysós) for gold

A chrysalis (Latin chrysallis, from Greek χρυσαλλίς = chrysallís, plural: chrysalides, also known as an aurelia) or nympha is the pupal stage of butterflies. The term is derived from the metallic–gold coloration found in the pupae of many butterflies, referred to by the Greek term χρυσός (chrysós) for gold.

When the caterpillar is fully grown, it makes a button of silk which it uses to fasten its body to a leaf or a twig. Then the caterpillar's skin comes off for the final time. Under this old skin is a hard skin called a chrysalis. [12]

Because chrysalises are often showy and are formed in the open, they are the most familiar examples of pupae. Most chrysalides are attached to a surface by a Velcro-like arrangement of a silken pad spun by the caterpillar, usually cemented to the underside of a perch, and the cremastral hook or hooks protruding from the rear of the chrysalis or cremaster at the tip of the pupal abdomen by which the caterpillar fixes itself to the pad of silk. (Gr. kremastos 'suspended') [13]

Like other types of pupae, the chrysalis stage in most butterflies is one in which there is little movement. However, some butterfly pupae are capable of moving the abdominal segments to produce sounds or to scare away potential predators. Within the chrysalis, growth and differentiation occur. [14] The adult butterfly emerges (ecloses) from this and expands its wings by pumping haemolymph into the wing veins. [15] Although this sudden and rapid change from pupa to imago is often called metamorphosis, metamorphosis is really the whole series of changes that an insect undergoes from egg to adult.

When emerging, the butterfly uses a liquid, sometimes called cocoonase, which softens the shell of the chrysalis. Additionally, it uses two sharp claws located on the thick joints at the base of the forewings to help make its way out. [16] Having emerged from the chrysalis, the butterfly will usually sit on the empty shell in order to expand and harden its wings. However, if the chrysalis was near the ground (such as if it fell off from its silk pad), the butterfly would find another vertical surface to rest upon and harden its wings (such as a wall or fence).

Moth pupae are usually dark in color and either formed in underground cells, loose in the soil, or their pupa is contained in a protective silk case called a cocoon. The pupa of some species such as the hornet moth develop sharp ridges around the outside called adminicula that allow the pupa to move from its place of concealment inside a tree trunk when it is time for the adult to emerge. [17]

Pupa, chrysalis, and cocoon are frequently confused, but are quite distinct from each other. The pupa is the stage between the larva and adult stages. The chrysalis generally refers to a butterfly pupa although the term may be misleading as there are some moths whose pupae resembles a chrysalis, e.g.: the plume winged moths of the family Pterophoridae and some geometrid moths. A cocoon is a silk case that the larvae of moths, and sometimes other insects, spin around the pupa.

Cocoon

The tough brown cocoon of an emperor gum moth Caterpillars cocoon.jpg
The tough brown cocoon of an emperor gum moth

A cocoon is a casing spun of silk by many moths and caterpillars, [18] and numerous other holometabolous insect larvae as a protective covering for the pupa.

Cocoons may be tough or soft, opaque or translucent, solid or meshlike, of various colors, or composed of multiple layers, depending on the type of insect larva producing it. Many moth caterpillars shed the larval hairs (setae) and incorporate them into the cocoon; if these are urticating hairs then the cocoon is also irritating to the touch. Some larvae attach small twigs, fecal pellets or pieces of vegetation to the outside of their cocoon in an attempt to disguise it from predators. Others spin their cocoon in a concealed location—on the underside of a leaf, in a crevice, down near the base of a tree trunk, suspended from a twig or concealed in the leaf litter. [19]

The silk in the cocoon of the silk moth can be unraveled to harvest silk fibre which makes this moth the most economically important of all lepidopterans. The silk moth is the only completely domesticated lepidopteran and does not exist in the wild.

Insects that pupate in a cocoon must escape from it, and they do this either by the pupa cutting its way out, or by secreting enzymes, sometimes called cocoonase, that soften the cocoon. Some cocoons are constructed with built-in lines of weakness along which they will tear easily from inside, or with exit holes that only allow a one-way passage out; such features facilitate the escape of the adult insect after it emerges from the pupal skin.

Puparium of Eupeodes americanus Eupeodes americanus.jpg
Puparium of Eupeodes americanus

Puparium

Some pupae remain inside the exoskeleton of the final larval instar and this last larval "shell" is called a puparium (plural, puparia). Flies of the group Muscomorpha have puparia, as do members of the order Strepsiptera, and the Hemipteran family Aleyrodidae. [20]

See also

Related Research Articles

Metamorphosis Profound change in body structure during the postembryonic development of an organism

Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insects, 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").

Lepidoptera Order of insects including moths and butterflies

Lepidoptera is an order of insects that includes butterflies and moths. About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 percent of the total described species of living organisms. It is one of the most widespread and widely recognizable insect orders in the world. The Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought, and is among the four most speciose orders, along with the Hymenoptera, Diptera, and Coleoptera.

A common classification of the Lepidoptera involves their differentiation into butterflies and moths. Butterflies are a natural monophyletic group, often given the suborder Rhopalocera, which includes Papilionoidea, Hesperiidae (skippers), and Hedylidae. In this taxonomic scheme, moths belong to the suborder Heterocera. Other taxonomic schemes have been proposed, the most common putting the butterflies into the suborder Ditrysia and then the "superfamily" Papilionoidea and ignoring a classification for moths.

<i>Manduca sexta</i> Species of moth

Manduca sexta is a moth of the family Sphingidae present through much of the American continent. The species was first described by Carl Linnaeus in his 1763 Centuria Insectorum.

Saturniidae Family of moths

Saturniidae, commonly known as saturniids, is a family of Lepidoptera with an estimated 2,300 described species. The family contains some of the largest species of moths in the world. Notable members include the emperor moths, royal moths, and giant silk moths.

<i>Opodiphthera eucalypti</i> Species of moth

Opodiphthera eucalypti, the emperor gum moth, is a species of moth in the family Saturniidae native to Australia. This species was formerly placed in the genus Antheraea.

Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago. Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygota. Immature stages of holometabolous insects are very different from the mature stage. In some species the holometabolous life cycle prevents larvae from competing with adults because they inhabit different ecological niches. The morphology and behavior of each stage are adapted for different activities. For example, larval traits maximize feeding, growth, and development, while adult traits enable dispersal, mating, and egg laying. Some species of holometabolous insects protect and feed their offspring. Other insect developmental strategies include ametabolism and hemimetabolism.

Codling moth Species of moth that feeds on fruit (Cydia pomonella)

The codling moth is a member of the Lepidopteran family Tortricidae. They are major pests to agricultural crops, mainly fruits such as apples and pears. Because the larvae are not able to feed on leaves, they are highly dependent on fruits as a food source and thus have a significant impact on crops. The caterpillars bore into fruit and stop it from growing, which leads to premature ripening. Various means of control, including chemical, biological, and preventive, have been implemented. This moth has a widespread distribution, being found on six continents. Adaptive behavior such as diapause and multiple generations per breeding season have allowed this moth to persist even during years of bad climatic conditions.

<i>Hyalophora cecropia</i> Species of moth

Hyalophora cecropia, the cecropia moth, is North America's largest native moth. It is a member of the family Saturniidae, or giant silk moths. Females have been documented with a wingspan of five to seven inches (160 mm) or more. These moths can be found all across North America as far west as Washington and north into the majority of Canadian provinces. Cecropia moth larvae are most commonly found on maple trees, but they have also been found on cherry and birch trees among many others. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.

<i>Citheronia regalis</i> Species of moth

Citheronia regalis, the regal moth or royal walnut moth, is a North American moth in the family Saturniidae. The caterpillars are called hickory horned devils. The adult (imago) has a wingspan of 3.75-6.1 in (9.5-15.5 cm). The species was first described by Johan Christian Fabricius in 1793.

<i>Automeris io</i> Species of moth

Automeris io, the Io moth, is a colorful North American moth in the family Saturniidae. The Io moth ranges from the southeast corner of Manitoba and in the southern extremes of Ontario, Quebec, New Brunswick and Nova Scotia in Canada, and in the US it is found from Montana, North Dakota, South Dakota, Nebraska, Colorado, New Mexico, Texas, Utah, east of those states and down to the southern end of Florida. The species was first described by Johan Christian Fabricius in 1775.

<i>Polygonia interrogationis</i> Species of butterfly

Polygonia interrogationis, the question mark, is a North American nymphalid butterfly. It lives in wooded areas, city parks, generally in areas with a combination of trees and open space. The color and textured appearance of the underside of its wings combine to provide camouflage that resembles a dead leaf. The adult butterfly has a wingspan of 4.5–7.6 cm (1.8–3.0 in). Its flight period is from May to September. "The silver mark on the underside of the hindwing is broken into two parts, a curved line and a dot, creating a ?-shaped mark that gives the species its common name."

Puriri moth Species of moth

The puriri moth, also commonly called the ghost moth or pepetuna, is a species of moth of the family Hepialidae. This moth is endemic to the North Island of New Zealand. It is New Zealand's largest moth, with a wingspan of up to 150 mm. It spends the first five to six years of its life as a grub in a tree trunk, with the last 48 hours of its life as a moth. Footage has been taken of a puriri moth chrysalis hatching over a period of one hour and forty minutes.

<i>Actias isis</i> Species of moth

Actias isis is a moth of the family Saturniidae first described by Léon Sonthonnax in 1899.

<i>Jalmenus evagoras</i> Species of butterfly

Jalmenus evagoras, the imperial hairstreak, imperial blue, or common imperial blue, is a small, metallic blue butterfly of the family Lycaenidae. It is commonly found in eastern coastal regions of Australia. This species is notable for its unique mutualism with ants of the genus Iridomyrmex. The ants provide protection for juveniles and cues for adult mating behavior. They are compensated with food secreted from J. evagoras larvae. The ants greatly enhance the survival and reproductive success of the butterflies. J. evagoras lives and feeds on Acacia plants, so butterfly populations are localized to areas with preferred species of both host plants and ants.

External morphology of Lepidoptera External features of butterflies and moths

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.

<i>Ochrogaster lunifer</i> Species of moth

Ochrogaster lunifer, the bag-shelter moth or processionary caterpillar, is a member of the family Notodontidae. The species was first described by Gottlieb August Wilhelm Herrich-Schäffer in 1855. Both the larval and adult forms have hairs that cause irritation of the skin (urticaria). The adult moth has a woolly appearance and its wings can grow to be about 5.5 cm across. The larvae feed on Grevillea striata at night and reside in brown silken bag nest during the day.

<i>Arsenura armida</i> Species of moth

Arsenura armida, the giant silk moth, is a moth of the family Saturniidae. It is found mainly in South and Central America, from Mexico to Bolivia, and Ecuador to south-eastern Brazil. It was first described by Pieter Cramer in 1779.

Madrone butterfly Species of butterfly

Eucheira socialis, commonly known as the Madrone butterfly is a lepidopteran that belongs to the family Pieridae. It was first described by Westwood in 1834. Locally known as Mariposa del madroño or tzauhquiocuilin, it is endemic to the highlands of Mexico, and exclusively relies on the Madrone as a host-plant. The species is of considerable interest to lepidopterists due to gregarious nest-building in the larval stages, and heavily male biased sex ratio. It takes an entire year for this adult butterfly to develop from an egg. The eggs are laid in the month of June and the adults emerge the following May–June. The adults have a black and white pattern on their wings, and the males are generally much smaller and paler than the females. The larvae do not undergo diapause and continue to feed and grow communally in the coldest months of the year. There are two subspecies of E. socialis, named E. socialis socialis and E. socialis westwoodi.

<i>Liothula omnivora</i> Species of moth

Liothula omnivora, the common bag moth, is a psychid moth endemic to New Zealand. It is also known by several Māori vernacular names like the tūngou ngou,< whare atua or kopi ('shut').

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