Epitoky
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Epitoky is a process that occurs in many species of
There are two methods in which epitoky can occur: schizogamy and epigamy.
Schizogamy
Many species go through schizogamy, where the atoke uses asexual reproduction to produce buds from its posterior end. Each bud develops into an epitoke and, once fully formed, will then break off from the atoke and become free-swimming. Many genetically identical epitokes are formed in this way, thus allowing a higher chance of finding a mate of the same species and subsequent passing of genes to the next generation. Atokes may then live through another season to form more epitokes.
Epigamy
Epigamy is another common way to form epitokes. For species that use this method, the atoke undergoes physiological and morphological modifications as it transforms into the epitoke. The majority of species that undergo epigamy are unable to revert to the atoke form and die after reproducing.
Male and female epitokes are produced and swim to the water's surface only at certain times of the year and are often synchronized with moon cycles in a behavior called swarming. Swarming brings individuals of the same species together so that there is an increased rate of fertilization.
In the past, epitokes were thought to be a separate group of polychaete marine worms, because epitokes may look very different than atokes. For instance, the atokes of Platynereis dumerilii are yellowish-brown, while the female epitokes are yellow because of the eggs they contain, and the male epitokes are white in the front part due to sperm and red in the hind part due to blood vessels[5] (see pictures).
References
- ISBN 978-0-07-352418-4.
- ^ .
- ^ ISBN 9789401728874.
- ISBN 9780495561972.
- PMID 21192805.
| Biological terms | |
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| Sexual reproduction |
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| Sexuality | |
