Pupa
A pupa (from
The pupae of different groups of insects have different names such as
Position in life cycle
The pupal stage follows the
Duration
The pupal stage may last weeks, months, or even years, depending on temperature and the species of insect.
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
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.[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]
- Decticous pupa – a pupa with articulated mandibles. Examples are pupae of the orders Trichoptera and few Lepidopterafamilies.
- Adecticous pupa – a pupa without articulated mandibles. Examples include the orders 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 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, ChalcidoideaHymenopterans)
- 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 (
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.[10]
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
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
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.[14] 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.[15]
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
Cocoon
A cocoon is a casing spun of
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 (
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; it 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
Some pupae remain inside the exoskeleton of the final larval
Gallery
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Fruit fly (Drosophila melanogaster) pupa
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Anemperor gum mothcaterpillar spinning its cocoon
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Luna mothcocoon and pupa
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Assortment of Luna moth cocoons
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Luna moth emerging from pupa withinsilk cocoon
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Luna moth pupa removed from cocoon
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Chrysalis of Gulf fritillary
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Pupation of Aglais io
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Monarch butterfly chrysalis
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Specimen of an eclosing Dryas iulia butterfly
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Pupae of Japanagromyza inferna, agall fly, in gall of Centrosema virginianum
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Pupa of cabbage looper
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Pupa of Baron Butterfly Euthalia aconthea
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Papilio_polytes_common_Mormon_pupa on curry leaves.
See also
References
- ISBN 0-03-096835-6.
- PMID 20504747.
- ^ Nielsen, Erik Tetens, and J. St Haeger. "Pupation and emergence in Aedes taeniorhynchus (Wied.)." Bulletin of Entomological Research 45.4 (1954): 757–768.
- ^ Elliott, J. M. "Temperature‐related fluctuations in the timing of emergence and pupation of Windermere alder‐flies over 30 years." Ecological Entomology 21.3 (1996): 241–247.
- ^ University of Minnesota Extension, Monarch Lab. "Monarch Life Cycle". Archived from the original on 7 July 2018. Retrieved 20 September 2017.
- ISBN 978-0-262-16137-4. Retrieved 16 November 2010.
- ISBN 978-0-226-06318-8. Retrieved 16 November 2010.
- OCLC 794624696.
- ^ "Types of Pupa". Agri Info. Archived from the original on 4 February 2017. Retrieved 28 April 2016.
- ^ Darby, Gene (1958). What is a Butterfly. Chicago: Benefic Press. p. 19.
- ^ "Academic Dictionaries and Encyclopedias". Archived from the original on 2013-05-25. Retrieved 2013-01-20.
- PMID 23676900.
- ^ AMNH Archived December 7, 2006, at the Wayback Machine Accessed December 2006
- ^ The Entomologist
- ^ Newland, D.E. "Eclosion mechanics, mating and ovipositing behaviour of Sesia apiformis". Entomologist's Gazette.
- ^ Darby, Gene (1958). What is a Butterfly. Chicago: Benefic Press. p. 41.
- ISBN 0-19-854031-0.
- ISBN 0-632-05343-7.
External links
- Pupa photos plus species descriptions at Insecta.pro
- Silk worm life cycle photos (archived 8 November 2012)