# Strobilation

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{{Single source|date=January 2025}}{{Short description|Form of asexual reproduction}}
'''Strobilation''' or '''transverse fission''' is a form of [asexual reproduction](/source/asexual_reproduction) consisting of the spontaneous transverse [segmentation](/source/Segmentation_(biology)) of the body. It is observed in certain [cnidarian](/source/cnidarian)s and [helminth](/source/helminth)s. This mode of reproduction is characterized by high offspring output, which, in the case of the [parasitic](/source/parasite) tapeworms, is of great significance.

==Strobilation in cnidarians==
*The process starts with preliminary [morphological](/source/Morphology_(biology)) changes. In particular, the [cnidarian's](/source/Cnidaria) tentacles tend to be reabsorbed.
*Neck-formation: transverse constrictions appear near the upper extremity of the animal. A strobilating [polyp](/source/Polyp_(zoology)) is called a '''strobila''' while the non-strobilating polyp is called a '''scyphistoma''' or '''scyphopolyp'''.
*[Segmentation](/source/Segmentation_(biology)): the number of constriction sites{{Technical inline|date=January 2025}} increases and migrates down the body length, transforming the body into a sequence of disks. The fissures intensify until the initial body is divided into equally spaced, separate segments. The oral end of the polyp becomes the oral end of the [ephyra](/source/Ephyrae).
*Metamorphosis: [neurosecretory](/source/neurosecretory) products of the two previous processes now disappear.

Neck-formation and segmentation are only separated for clarity purposes. In reality, the two processes are simultaneous, with segmentation to release new ephyras occurring at the upper end while neck formation spreads further down the body. Usually, a portion of the animal remains adhered to the [substrate](/source/Substrate_(biology)) and regenerates the body.

===Examples===
*The [moon jellyfish](/source/moon_jellyfish) (''Aurelia aurita'') reproduces both [sexually](/source/Sexual_reproduction) and by strobilation. This latter process occurs during the colonial [polyp](/source/polyp_(zoology)) stage and produces either polyps or juvenile [Medusae](/source/Medusa_(biology)) called [ephyra](/source/Jellyfish). Strobilation tend to occur at specific periods, typically early spring. As ephyra size remains constant regardless of the polyp size, larger polyps produce more numerous ephyras.
*Some [scyphozoa](/source/scyphozoa)ns, such as ''[Nausithoe aurea](/source/Nausithoe_aurea)'', cnidarians also strobilate in their solitary polyp form, producing either ephyra or [planuloid](/source/planuloid)s. Strobilation does not happen periodically, but is thought to be induced by external stimuli, such as [iodine](/source/iodine), light regime, temperature, or food availability.

===Induction in laboratory conditions===
Strobilation is successfully induced in [laboratory conditions](/source/laboratory_conditions) by intensive feeding and temperature lowering, and also by the effect of artificial compounds.

==Strobilation in helminths==
In [cestode](/source/cestode)s, the whole body except for the head and the neck undergoes strobilation continuously, reflecting the important role reproduction plays in the parasitic mode of life. The strobilating section is called strobila, and each of its segments is a [proglottid](/source/proglottid). As they mature, proglottids are disposed in the [feces](/source/feces) of the host. <ref name="Paludo Thompson Miyamoto Guedes p. ">{{cite journal | last1=Paludo | first1=Gabriela Prado | last2=Thompson | first2=Claudia Elizabeth | last3=Miyamoto | first3=Kendi Nishino | last4=Guedes | first4=Rafael Lucas Muniz | last5=Zaha | first5=Arnaldo | last6=de Vasconcelos | first6=Ana Tereza Ribeiro | last7=Cancela | first7=Martin | last8=Ferreira | first8=Henrique Bunselmeyer | title=Cestode strobilation: prediction of developmental genes and pathways | journal=BMC Genomics | publisher=Springer Science and Business Media LLC | volume=21 | issue=1 | date=2020-07-16 | issn=1471-2164 | doi=10.1186/s12864-020-06878-3 | page=487| doi-access=free | pmid=32677885 | pmc=7367335 }}</ref>

==References==
{{Reflist}}

Category:Reproduction in animals
Category:Scyphozoa

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Adapted from the Wikipedia article [Strobilation](https://en.wikipedia.org/wiki/Strobilation) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Strobilation?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.