Kleptocnidy
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Kleptocnidy (/klɛptoʊnaɪdiː/ klept-oh-NY-dee), or nematocyst sequestration, is the process whereby organisms take and make use of the cnidocysts (stinging organelles, also known as nematocysts) of digested prey. Sequestered cnidocysts are known as kleptocnidae, and are used for defense or to capture prey. The animals preyed on for their cnidocysts are cnidarians, the group that includes jellyfish, hydroids, sea anemones, corals, among others.[1] Nematocysts in cnidarians could have originated from a horizontal gene transfer event between the cnidarians last common ancestor, and predatory dinoflagellates of the families Warnowiaceae and Polykrikaceae.[2]
Etymology
The word "kleptocnidy" comes from the Ancient Greek words κλέπτης (kleptés, "to steal"), and κνίδη (knídē, "sea nettle"). The latter is commonly used in words relating to the phylum Cnidaria, which contains all animals that produce cnidocysts.[3]
Process
Kleptocnidy occurs as a specialized form of phagocytosis, whereby cells engulf cnidocysts without triggering them.[4]
Haeckelia comb jellies pass cnidocysts from their stomach down tentacular canals, to line their tentacles for use in capturing prey.[1][5] This is reported in all species but H. filigera, where the process has not been described.[1]
Most flatworms capable of kleptocnidy have cells called cyst cells or cnidophages to deliver nematocysts from their digestive tract to their epidermis for defense.[1]
Nudibranchs capable of kleptocnidy have branched digestive glands and have cerata that are tipped with cnidosacs, such that cnidocysts are passed directly from digestion to their cnidosacs for use. To protect themselves from nematocysts firing in their digestive tract, aeolid nudibranchs have a hard cuticle lining their esophagus and have a mucus that chemically inhibits nematocyst discharge and while providing an additional barrier.[6] These nudibranchs use the cnidocysts for defense and capturing prey.[4][6]
Occurrence
Kleptocnidy has evolved independently in various marine animals, including ctenophores, acoels, flatworms, and molluscs. Below is a table outlining the various occurrences of kleptocnidy, given by Goodheart et. al., with the addition of the representatives of the process for some of the taxa[1]
| Phylum | Order | Number of species | Representative(s) | Inferred number of origins |
|---|---|---|---|---|
| Ctenophora | Cydippida | 3 | Haeckelia rubra, H. bimaculata, H. beehleri | 1 |
| Acoelomorpha | Acoela | 1 | Childia dubium | 1 |
| Platyhelminthes | Catenulida | 1 | Stenostomum sieboldi | 6–13 |
| Macrostomorpha | 12 | Microstomum spp. | ||
| Proseriata | 5 | Archimonocelis spp. | ||
| Prolecithophora | 4 | Ulianinia mollissima, U. westbladi, Pseudostomum klostermanni, Cylindrostoma monotrochum | ||
| Polycladida | 9 | Stylochoplana tarda, S. inquilina, Anonymus, Chromoplana bella, Amakusaplana acroporae, Amyella, Theama sp. | ||
| Rhabdocoela | 1 | Wahlia macrostylifera | ||
| Mollusca | Nudibranchia | ~600 | Aeolidida, Hancockia spp. | 1–2 |
Aeolidida is the primary clade in Nudibranchia that perform kleptocnidy, though there are a few in the unplaced genus Hancockia that can as well.[1] Kleptocnidy occurs in a range of Platyhelminthes.[1][6]
See also
References
- 1 2 3 4 5 6 7 Goodheart, Jessica A.; Bely, Alexandra E. (March 2017). "Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution". Invertebrate Biology. 136 (1): 75–91. Bibcode:2017InvBi.136...75G. doi:10.1111/ivb.12154. ISSN 1077-8306.
- ↑ Hwang, Jung Shan; Nagai, Satoshi; Hayakawa, Shiho; Takaku, Yasuharo; Gojibori, Takashi (2008). "The Search for the Origin of Cnidarian Nematocysts in Dinoflagellates". In Pontarotti, Pierre (ed.). Evolutionary biology from concept to application. Berlin: Springer. ISBN 978-3-540-78992-5.
- ↑ American Heritage Dictionaries (2016). The American Heritage Dictionary of the English Language (5th ed.). Houghton Mifflin Harcourt. ISBN 9780544454453.
- 1 2 Goodheart, Jessica A.; Fiorenza, Rose; Rio, Robin; Lopez-Anido, Rebecca N.; Martin, Noah J.; Herrlinger, Timothy J.; Tarvin, Rebecca D.; Lyons, Deirdre C. (2025-06-28). "A subset of conserved phagocytic genes are likely used for the intracellular theft of cnidarian stinging organelles in nudibranch gastropods". EvoDevo. 16 (1) 10. doi:10.1186/s13227-025-00241-x. ISSN 2041-9139. PMC 12205514. PMID 40581638.
- ↑ Mills, C. E.; Miller, R. L. (1984). "Ingestion of a medusa (Aegina citrea) by the nematocyst-containing ctenophore Haeckelia rubra (formerly Euchlora rubra): phylogenetic implications". Marine Biology. 78 (2): 215–221. Bibcode:1984MarBi..78..215M. doi:10.1007/BF00394704. ISSN 0025-3162.
- 1 2 3 Greenwood, Paul G. (December 2009). "Acquisition and use of nematocysts by cnidarian predators". Toxicon. 54 (8): 1065–1070. Bibcode:2009Txcn...54.1065G. doi:10.1016/j.toxicon.2009.02.029. PMC 2783962. PMID 19269306.