Editing Cnidocyte (section)

== Nematocyst toxicity ==
[[File:Chironex fleckeri nematocysts 01.jpg|thumb|Nematocysts from ''[[Chironex fleckeri]]'' (400x magnification).]]
Nematocysts are very efficient weapons. A single nematocyst has been shown to suffice in paralyzing a small [[arthropod]] (''[[Drosophila]]'' [[larva]]). The most deadly cnidocytes (to humans, at least) are found on the body of a [[box jellyfish]].<ref name="pmid16928389">{{cite journal |author=Tibballs J |title=Australian venomous jellyfish, envenomation syndromes, toxins and therapy |journal=Toxicon |volume=48 |issue=7 |pages=830–59 |date=December 2006 |pmid=16928389 |doi=10.1016/j.toxicon.2006.07.020 }}</ref><ref name="pmid17688901">{{cite journal |vauthors=Brinkman D, Burnell J |title=Identification, cloning and sequencing of two major venom proteins from the box jellyfish, Chironex fleckeri |journal=Toxicon |volume=50 |issue=6 |pages=850–60 |date=November 2007 |pmid=17688901 |doi=10.1016/j.toxicon.2007.06.016 }}</ref><ref name="pmid18243272">{{cite journal |vauthors=Brinkman D, Burnell J |title=Partial purification of cytolytic venom proteins from the box jellyfish, Chironex fleckeri |journal=Toxicon |volume=51 |issue=5 |pages=853–63 |date=April 2008 |pmid=18243272 |doi=10.1016/j.toxicon.2007.12.017 }}</ref> One member of this family, the sea wasp, ''[[Chironex fleckeri]]'', is "claimed to be the most venomous marine animal known," according to the [[Australian Institute of Marine Science]]. It can cause excruciating pain to humans, sometimes followed by death. Other cnidarians, such as the jellyfish ''[[Lion's mane jellyfish|Cyanea capillata]]'' (the "[[The Adventure of the Lion's Mane|Lion's Mane]]" made famous by [[Sherlock Holmes]]) or the siphonophore ''Physalia physalis'' ([[Portuguese man o' war]], "Bluebottle") can cause extremely painful and sometimes fatal stings. On the other hand, [[Shoaling and schooling|aggregating]] sea anemones may have the lowest sting intensity, perhaps due to the inability of the nematocysts to penetrate the skin, creating a feeling similar to touching sticky candies. Besides feeding and defense, sea anemone and coral colonies use cnidocytes to sting one another in order to defend or win space.<ref>{{cite web|url=https://www.youtube.com/watch?v=WQEiYWGitKs| archive-url=https://web.archive.org/web/20140609073538/http://www.youtube.com/watch?v=WQEiYWGitKs| archive-date=2014-06-09 | url-status=dead|title=YouTube|website=www.youtube.com|access-date=6 April 2018}}</ref> Despite their effectiveness in prey-predator interactions, there is an evolutionary tradeoff as cnidarian venom systems are known to reduce the cnidarian's reproductive fitness and overall growth.<ref>{{Cite report |url=http://biorxiv.org/lookup/doi/10.1101/2023.07.24.550294 |title=Venom tradeoff shapes interspecific interactions, physiology and reproduction |last1=Surm |first1=Joachim M. |last2=Birch |first2=Sydney |date=2023-07-26 |publisher=Evolutionary Biology |doi=10.1101/2023.07.24.550294 |language=en |last3=Macrander |first3=Jason |last4=Jaimes-Becerra |first4=Adrian |last5=Fridrich |first5=Arie |last6=Aharoni |first6=Reuven |last7=Rozenblat |first7=Rotem |last8=Sharabany |first8=Julia |last9=Appelbaum |first9=Lior}}</ref>

[[Venom]] from animals such as cnidarians, [[scorpion]]s and [[spider]]s may be species-specific. A substance that is weakly toxic for humans or other mammals may be strongly toxic to the natural prey or predators of the venomous animal. Such specificity has been used to create new medicines and bioinsecticides, and [[biopesticides]].

Animals in the phylum [[Ctenophora]] ("sea-gooseberries" or "comb jellies") are transparent and jelly-like but have no nematocysts, and are harmless to humans.

Certain types of sea slugs, such as the nudibranch aeolids, are known to undergo kleptocnidy (in addition to [[kleptoplasty]]), whereby the organisms store nematocysts of digested prey at the tips of their cerata.