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A pupa ( la, 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 Juvenile hormones (JHs) are a group of acyclic sesquiterpenoids that regulate many aspects of insect physiology. The first discovery of a JH was by Vincent Wigglesworth. JHs regulate development, reproduction, diapause, and polyphenisms.The chem ...
,
prothoracicotropic hormone Prothoracicotropic hormone (PTTH) was the first insect hormone to be discovered.The chemical symbol for prothoracicotropic hormone is (C64H102N16O19S2). It was originally described simply as "brain hormone" by early workers such as Stefan Kopeć (1 ...
, 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. The pupae of different groups of insects have different names such as ''chrysalis'' for the pupae of
butterflies Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group comprises ...
and ''tumbler'' for those of the mosquito family. Pupae may further be enclosed in other structures such as cocoons,
nest A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materia ...
s, or shells.


Position in life cycle

The pupal stage follows the larval stage and precedes
adult An adult is a human or other animal that has reached full growth. In human context, the term ''adult'' has meanings associated with social and legal concepts. In contrast to a " minor", a legal adult is a person who has attained the age of major ...
hood ('' imago'') in insects with complete metamorphosis. The pupa is a non-feeding, usually
sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...
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 disc An imaginal disc is one of the parts of a holometabolous insect larva that will become a portion of the outside of the adult insect during the pupal transformation. Contained within the body of the larva, there are pairs of discs that will form ...
s.


Duration

The pupal stage may last weeks, months, or even years, depending on temperature and the species of insect. For example, the pupal stage lasts eight to fifteen days in
monarch butterflies The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. ...
. The pupa may enter dormancy or
diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press I ...
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.


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 biology, exuviae are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have moulted. The exuviae of an animal can be important to biologists as they can often be ...
''; in most
hymenopteran Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typica ...
s (ants, bees and wasps) the exuvia is so thin and membranous that it becomes "crumpled" as it is shed.


Pupal mating

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.


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. 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
mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
s that are employed in emerging from a cocoon or pupal case, the pupae can be classified in to two types: * Decticous pupa – a pupa with articulated mandibles. Examples are pupae of the orders Neuroptera,
Mecoptera Mecoptera (from the Greek: ''mecos'' = "long", ''ptera'' = "wings") is an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their lar ...
,
Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...
and few Lepidoptera families. * Adecticous pupa – a pupa without articulated mandibles. Examples include the orders Strepsiptera,
Coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describe ...
, Hymenoptera, Diptera and Siphonaptera. Based on whether the pupal appendages are free or attached to the body, the pupae can be classified as one of three types: * Exarate pupa – appendages are free and are not usually encapsulated within a cocoon. Decticous pupae are always exarate; some adecticous pupae are as well. (Neuroptera, Trichoptera,
Cyclorrhapha Cyclorrhapha is an unranked taxon within the infraorder Muscomorpha. They are called "Cyclorrhapha" ('circular-seamed flies') with reference to the circular aperture through which the adult escapes the puparium. This is a circumscriptional name t ...
of Dipterans, Siphonaptera, most Coleoptera, Hymenoptera, and few Lepidoptera). * Obtect pupa – appendages are attached closely to the body and are commonly encapsulated within a cocoon. Some adecticous pupa are obtect forms. (Most Lepidoptera,
Nematocera The Nematocera (the name means "thread-horns") are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera (the name means "sh ...
and
Brachycera The Brachycera are a suborder of the order Diptera. It is a major suborder consisting of around 120 families. Their most distinguishing characteristic is reduced antenna segmentation. Description A summary of the main physical characteristics i ...
of Dipterans,
Staphylinidae The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra (wing covers) that typically leave more than half of their abdominal segments exposed. With roughly 63,000 species in thousands of genera, the ...
and
Chrysomelidae The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...
Coleopterans, many
Chalcidoidea Chalcid wasps (, , for their metallic colour) are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, me ...
Hymenopterans) * Coarctate pupa – enclosed in a hardened cuticle of the penultimate larval instar called a puparium. However, the pupa itself is of the exarate adecticous pupal form. (Cyclorrhapha of Dipterans).


Chrysalis

A chrysalis ( la, chrysallis, from grc, χρυσαλλίς, , plural: , also known as an ''aurelia'') or nympha is the pupal stage of
butterflies Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group comprises ...
. The term is derived from the metallic–gold coloration found in the pupae of many butterflies, referred to by the Ancient Greek term () 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. 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 Velcro, officially known as Velcro IP Holdings LLC and trading as Velcro Companies, is a British privately held company, founded by Swiss electrical engineer George de Mestral in the 1950s. It is the original manufacturer of hook-and-loop fasten ...
-like arrangement of a silken pad spun by the
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symph ...
, 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 The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...
by which the caterpillar fixes itself to the pad of silk. ( 'suspended') 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. The adult butterfly emerges (ecloses) from this and expands its wings by pumping haemolymph into the wing veins. 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 Cocoonase is a trypsin-like proteolytic enzyme produced by silkworms (of both ''Bombyx'' and ''Antheraea'' species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis and exuded onto the galeae. Its fu ...
, 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. 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 The hornet moth or hornet clearwing (''Sesia apiformis'') is a large moth native to Europe and the Middle East and has been introduced to North America. Its protective coloration is an example of Batesian mimicry, as its similarity to a hornet ...
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. 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 The Pterophoridae or plume moths are a family of Lepidoptera with unusually modified wings. Though they belong to the Apoditrysia like the larger moths and the butterflies, unlike these they are tiny and were formerly included among the assembla ...
and some
geometrid The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek ''geo'' γεω (derivative form of or "the earth"), and ''metr ...
moths. A cocoon is a silk case that the larvae of moths, and sometimes other insects, spin around the pupa.


Cocoon

A cocoon is a casing spun of silk by many moths and
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symph ...
s, 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 A crevice is a fracture or fissure in rock. Crevice may also refer to: * Crevice corrosion, occurs in spaces to which the access of corrosion-resistant fluid is limited * Crevice kelpfish (''Gibbonsia montereyensis''), a species of subtropical c ...
, down near the base of a
tree trunk In botany, the trunk (or bole) is the stem and main wooden axis of a tree, which is an important feature in tree identification, and which often differs markedly from the bottom of the trunk to the top, depending on the species. The trunk is the ...
, suspended from a twig or concealed in the
leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...
. 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 Cocoonase is a trypsin-like proteolytic enzyme produced by silkworms (of both ''Bombyx'' and ''Antheraea'' species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis and exuded onto the galeae. Its fu ...
, 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

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 The Brachyceran infraorder Muscomorpha is a large and diverse group of flies, containing the bulk of the Brachycera, and, most of the known flies. It includes a number of the most familiar flies, such as the housefly, the fruit fly, and the blo ...
have puparia, as do members of the order Strepsiptera, and the
Hemiptera 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 to aroun ...
n family
Aleyrodidae Whiteflies are Hemipterans that typically feed on the undersides of plant leaves. They comprise the family Aleyrodidae, the only family in the superfamily Aleyrodoidea. More than 1550 species have been described. Description and taxonomy The A ...
.


Gallery

File:Fruit Fly Pupa.jpg, Fruit fly ('' Drosophila melanogaster'') pupa File:Caterpillar making cocoon2.jpg, An emperor gum moth caterpillar spinning its cocoon File:Actias luna pupa 2 sjh.JPG,
Luna moth The Luna moth (''Actias luna'') also known as the American moon moth is a Nearctic moth in the family Saturniidae, subfamily Saturniinae, a group commonly known as giant silk moths. It has lime-green colored wings and a white body. The larvae ( ...
cocoon and pupa File:Actias luna cocoons sjh.JPG, Assortment of Luna moth cocoons File:Actias luna emergence sjh.gif, Luna moth emerging from pupa within
silk cocoon A pupa ( la, 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 ...
File:Actias luna pupa sjh enhanced.JPG, Luna moth pupa removed from cocoon File:Chrysalis5504.jpg, Chrysalis of
Gulf fritillary The Gulf fritillary or passion butterfly (''Dione vanillae'') is a bright orange butterfly in the subfamily Heliconiinae of the family Nymphalidae. That subfamily was formerly set apart as a separate family, the Heliconiidae. The Heliconiinae ...
File:Pupation - Inachis io.jpg, Pupation of '' Aglais io'' File:Monarch Butterfly Chrysalis.JPG,
Monarch butterfly The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. ...
chrysalis File:Nacimiento de una Dryas iulia, Mariposario de Icod de los Vinos, Tenerife, España, 2012-12-13, DD 03.jpg, Specimen of an eclosing '' Dryas iulia'' butterfly File:Pupae of Japanagromyza inferna Spencer in gall of Centrosema virginianum L. - ZooKeys-374-045-g005.jpg, Pupae of ''Japanagromyza inferna'', a gall fly, in gall of '' Centrosema virginianum'' File:Cabbage looper in cocoon.jpg, Pupa of
cabbage looper The cabbage looper (''Trichoplusia ni'') is a medium-sized moth in the family Noctuidae, a family commonly referred to as owlet moths. Its common name comes from its preferred host plants and distinctive crawling behavior. Cruciferous vegetable ...
File:BARON BUTTERFLY CHRYSALIS.jpg, Pupa of Baron Butterfly
Euthalia aconthea ''Euthalia aconthea'', the common baron, often called simply baron, is a medium-sized nymphalid butterfly native to Sri Lanka, India and southeast Asia. It flies with stiff wing beats and often glides. The wing is not flapped very far below the ...
File:Papilio polytes common Mormon pupa vijayanrajapuram 03.jpg, Papilio_polytes_common_Mormon_pupa on curry leaves.


See also

*
Brood (honeybee) In beekeeping, bee brood or brood refers to the eggs, larvae and pupae of honeybees. The brood of Western honey bees develops within a bee hive. In man-made, removable frame hives, such as Langstroth hives, each frame which is mainly occupied by ...
* Larva * Silk


References


External links


Pupa photos
plus species descriptions at ''Insecta.pro''
Silk worm life cycle photos
{{Authority control Insect physiology Insect developmental biology Articles containing video clips