Earth:Kleptocnidy
Kleptocnidy (/klɛptoʊnaɪdiː/ klept-oh-NY-dee), or nematocyst sequestration, is the process whereby organisms take and make use of the cnidocytes (stingers, also known as nematocysts) of digested prey. Sequestered cnidocytes are known as kleptocnidae, and are used for defense or to capture prey. Sea creatures preyed on for their cnidocytes include jellyfish, hydroids, sea anemones, corals, and other cnidarians with cnidocytes.[1]
Etymology
The word Kleptocnidy comes from the Ancient Greek words κλέπτης (kleptés), "to steal", and κνίδη (knídē), "sea nettle" – the word used for the phylum Cnidaria, which contains all animals with cnidocytes.[2]
Process
Kleptocnidy occurs as a specialized form of phagocytosis, whereby cells engulf cnidocytes without triggering them.[3]
Haeckelia comb jellies pass cnidocytes from their stomach down tentacular canals, to line their tentacles for use in capturing prey.[1][4]
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 cnidocytes 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.[5] Nudibranchs use the cnidocytes for defense and capturing prey.[3][5]
Occurrence
It has evolved independently in various sea creatures, including Ctenophora, Acoelomorpha, Platyhelminthes, and Mollusca. Below is a table outlining the various occurrences of Kleptocnidy, given by Goodheart et al.[1]
| Phylum | Order | No of Species | Inferred No of Origins |
|---|---|---|---|
| Ctenophora | Cydippida | 3 | 1 |
| Acoelomorpha | Acoela | 1 | 1 |
| Platyhelminthes | Catenulida | 1 | 6–13 |
| Macrostomorpha | 12 | ||
| Proseriata | 5 | ||
| Prolecithophora | 4 | ||
| Polycladida | 9 | ||
| Rhabdocoela | 1 | ||
| Mollusca | Nudibranchia | ~600 | 1–2 |
Haeckelia is the genus in Cydippida that performs kleptocnidy. Childia dubium is the species in Acoela to do so. Aeolidida is the primary clade in Nudibranchia that perform kleptocnidy, though there are a few in the unplaced genus Hancockia that can as well. Kleptocnidy occurs in a range Platyhelminthes.[1][5]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Goodheart, Jessica A.; Bely, Alexandra E. (March 2017). "Sequestration of nematocysts by divergent cnidarian predators: mechanism, function, and evolution" (in en). Invertebrate Biology 136 (1): 75–91. doi:10.1111/ivb.12154. ISSN 1077-8306. Bibcode: 2017InvBi.136...75G. https://onlinelibrary.wiley.com/doi/10.1111/ivb.12154.
- ↑ American Heritage Dictionaries (2016). The American Heritage Dictionary of the English Language (5th ed.). Houghton Mifflin Harcourt. ISBN 9780544454453.
- ↑ 3.0 3.1 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" (in en). EvoDevo 16 (1). doi:10.1186/s13227-025-00241-x. ISSN 2041-9139. 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" (in en). Marine Biology 78 (2): 215–221. doi:10.1007/BF00394704. ISSN 0025-3162. Bibcode: 1984MarBi..78..215M. http://link.springer.com/10.1007/BF00394704.
- ↑ 5.0 5.1 5.2 Greenwood, Paul G. (December 2009). "Acquisition and use of nematocysts by cnidarian predators" (in en). Toxicon 54 (8): 1065–1070. doi:10.1016/j.toxicon.2009.02.029. PMID 19269306. Bibcode: 2009Txcn...54.1065G.
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