Venom

This article is about the class of biotoxins. For other uses, see Venom (disambiguation) and Venomous (disambiguation).

Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action.^[1][2][3] The toxin is delivered through a specially evolved venom apparatus, such as fangs or a stinger, in a process called envenomation.^[2] Venom is often distinguished from poison, which is a toxin that is passively delivered by being ingested, inhaled, or absorbed through the skin,^[4] and toxungen, which is actively transferred to the external surface of another animal via a physical delivery mechanism.^[5]

Wasp stinger with a droplet of venom

Venom has evolved in terrestrial and marine environments and in a wide variety of animals: both predators and prey, and both vertebrates and invertebrates. Venoms kill through the action of at least four major classes of toxin, namely necrotoxins and cytotoxins, which kill cells; neurotoxins, which affect nervous systems; myotoxins, which damage muscles; and haemotoxins, which disrupt blood clotting. Venomous animals cause tens of thousands of human deaths per year.

Venoms are often complex mixtures of toxins of differing types. Toxins from venom are used to treat a wide range of medical conditions including thrombosis, arthritis, and some cancers. Studies in venomics are investigating the potential use of venom toxins for many other conditions.

Evolution

Further information: Evolution of snake venom

The use of venom across a wide variety of taxa is an example of convergent evolution. It is difficult to conclude exactly how this trait came to be so intensely widespread and diversified. The multigene families that encode the toxins of venomous animals are actively selected, creating more diverse toxins with specific functions. Venoms adapt to their environment and victims, evolving to become maximally efficient on a predator's particular prey (particularly the precise ion channels within the prey). Consequently, venoms become specialized to an animal's standard diet.^[6]

Mechanisms

Main article: Toxin

 

Phospholipase A2, an enzyme in bee venom, releases fatty acids, affecting calcium signalling.

Venoms cause their biological effects via the many toxins that they contain; some venoms are complex mixtures of toxins of differing types. Major classes of toxin in venoms include:^[7]

• Necrotoxins, which cause necrosis (i.e., death) in the cells they encounter. The venoms of vipers and bees contain phospholipases; viper venoms often also contain trypsin-like serine proteases.^[8]
• Neurotoxins, which primarily affect the nervous systems of animals, such as ion channel toxins. These are found in many venomous taxa, including black widow spiders, scorpions, box jellyfish, cone snails, centipedes and blue-ringed octopuses.^[9]
• Myotoxins, which damage muscles by binding to a receptor. These small, basic peptides are found in snake (such as rattlesnake) and lizard venoms.^{[10][11][12][13]}
• Cytotoxins, which kill individual cells and are found in the apitoxin of honey bees and the venom of black widow spiders.^[14][15]

Taxonomic range

Venom is widely distributed taxonomically, being found in both invertebrates and vertebrates, in aquatic and terrestrial animals, and among both predators and prey. The major groups of venomous animals are described below.

Arthropods

Venomous arthropods include spiders, which use fangs on their chelicerae to inject venom, and centipedes, which use forcipules — modified legs — to deliver venom, while scorpions and stinging insects inject venom with a sting. In bees and wasps, the stinger is a modified ovipositor (egg-laying device). In Polistes fuscatus, the female continuously releases a venom that contains a sex pheromone that induces copulatory behavior in males.^[16] In wasps such as Polistes exclamans, venom is used as an alarm pheromone, coordinating a response with from the nest and attracting nearby wasps to attack the predator.^[17] In some species, such as Parischnogaster striatula, venom is applied all over the body as an antimicrobial protection.^[18]

Many caterpillars have defensive venom glands associated with specialized bristles on the body called urticating hairs. These are usually merely irritating, but those of the Lonomia moth can be fatal to humans.^[19]

Bees synthesize and employ an acidic venom (apitoxin) to defend their hives and food stores, whereas wasps use a chemically different venom to paralyse prey, so their prey remains alive to provision the food chambers of their young. The use of venom is much more widespread than just these examples; many other insects, such as true bugs and many ants, also produce venom.^[20] The ant species Polyrhachis dives uses venom topically for the sterilisation of pathogens.^[21]

Other invertebrates

 

The fingernail-sized box jellyfish Malo kingi has among the most dangerous venom of any animal, causing Irukandji syndrome⁠ — severe pain, vomiting, and rapid rise in blood pressure

There are venomous invertebrates in several phyla, including jellyfish such as the dangerous box jellyfish,^[22] the Portuguese man-of-war (a siphonophore) and sea anemones among the Cnidaria,^[23] sea urchins among the Echinodermata,^[24] and cone snails^[25] and cephalopods, including octopuses, among the Molluscs.^[26]

Vertebrates

Fish

Main article: Venomous fish

Venom is found in some 200 cartilaginous fishes, including stingrays, sharks, and chimaeras; the catfishes (about 1000 venomous species); and 11 clades of spiny-rayed fishes (Acanthomorpha), containing the scorpionfishes (over 300 species), stonefishes (over 80 species), gurnard perches, blennies, rabbitfishes, surgeonfishes, some velvetfishes, some toadfishes, coral crouchers, red velvetfishes, scats, rockfishes, deepwater scorpionfishes, waspfishes, weevers, and stargazers.^[27]

Amphibians

Some salamanders can extrude sharp venom-tipped ribs.^[28][29] Two frog species in Brazil have tiny spines around the crown of their skulls which, on impact, deliver venom into their targets.^[30]

Reptiles

Further information: Big Four (Indian snakes)

Main articles: Snake venom and Evolution of snake venom

 

 

The venom of the prairie rattlesnake, Crotalus viridis (left), includes metalloproteinases (example on the right) which help digest prey before eating.

Some 450 species of snake are venomous.^[27] Snake venom is produced by glands below the eye (the mandibular glands) and delivered to the target through tubular or channeled fangs. Snake venoms contain a variety of peptide toxins, including proteases, which hydrolyze protein peptide bonds; nucleases, which hydrolyze the phosphodiester bonds of DNA; and neurotoxins, which disrupt signalling in the nervous system.^[31] Snake venom causes symptoms including pain, swelling, tissue necrosis, low blood pressure, convulsions, haemorrhage (varying by species of snake), respiratory paralysis, kidney failure, coma, and death.^[32] Snake venom may have originated with duplication of genes that had been expressed in the salivary glands of ancestors.^[33][34]

Venom is found in a few other reptiles such as the Mexican beaded lizard,^[35] the gila monster,^[36] and some monitor lizards, including the Komodo dragon.^[37] Mass spectrometry showed that the mixture of proteins present in their venom is as complex as the mixture of proteins found in snake venom.^[37][38] Some lizards possess a venom gland; they form a hypothetical clade, Toxicofera, containing the suborders Serpentes and Iguania and the families Varanidae, Anguidae, and Helodermatidae.^[39]

Mammals

Main article: Venomous mammal

Euchambersia, an extinct genus of therocephalians, is hypothesized to have had venom glands attached to its canine teeth.^[40]

A few species of living mammals are venomous, including solenodons, shrews, vampire bats, male platypuses, and slow lorises.^[27][41] Shrews have venomous saliva and most likely evolved their trait similarly to snakes.^[42] The presence of tarsal spurs akin to those of the platypus in many non-therian Mammaliaformes groups suggests that venom was an ancestral characteristic among mammals.^[43]

Extensive research on platypuses shows that their toxin was initially formed from gene duplication, but data provides evidence that the further evolution of platypus venom does not rely as much on gene duplication as was once thought.^[44] Modified sweat glands are what evolved into platypus venom glands. Although it is proven that reptile and platypus venom have independently evolved, it is thought that there are certain protein structures that are favored to evolve into toxic molecules. This provides more evidence of why venom has become a homoplastic trait and why very different animals have convergently evolved.^[13]

Venom and humans

Envenomation resulted in 57,000 human deaths in 2013, down from 76,000 deaths in 1990.^[45] Venoms, found in over 173,000 species, have potential to treat a wide range of diseases, explored in over 5,000 scientific papers.^[36]

In medicine, snake venom proteins are used to treat conditions including thrombosis, arthritis, and some cancers.^[46][47] Gila monster venom contains exenatide, used to treat type 2 diabetes.^[36] Solenopsins extracted from fire ant venom has demonstrated biomedical applications, ranging from cancer treatment to psoriasis.^[48][49] A branch of science, venomics, has been established to study the proteins associated with venom and how individual components of venom can be used for pharmaceutical means.^[50]

Resistance

Further information: Antipredator adaptations

 

 

The California ground squirrel is resistant to the Northern Pacific rattlesnake's powerful venom.

Venom is used as a trophic weapon by many predator species. The coevolution between predators and prey is the driving force of venom resistance, which has evolved multiple times throughout the animal kingdom.^[51] The coevolution between venomous predators and venom-resistant prey has been described as a chemical arms race.^[52] Predator/prey pairs are expected to coevolve over long periods of time.^[53] As the predator capitalizes on susceptible individuals, the surviving individuals are limited to those able to evade predation.^[54] Resistance typically increases over time as the predator becomes increasingly unable to subdue resistant prey.^[55] The cost of developing venom resistance is high for both predator and prey.^[56] The payoff for the cost of physiological resistance is an increased chance of survival for prey, but it allows predators to expand into underutilised trophic niches.^[57]

The California ground squirrel has varying degrees of resistance to the venom of the Northern Pacific rattlesnake.^[58] The resistance involves toxin scavenging and depends on the population. Where rattlesnake populations are denser, squirrel resistance is higher.^[59] Rattlesnakes have responded locally by increasing the effectiveness of their venom.^[60]

The kingsnakes of the Americas are constrictors that prey on many venomous snakes.^[61] They have evolved resistance which does not vary with age or exposure.^[55] They are immune to the venom of snakes in their immediate environment, like copperheads, cottonmouths, and North American rattlesnakes, but not to the venom of, for example, king cobras or black mambas.^[62]

 

Ocellaris clownfish always live among venomous sea anemone tentacles and are resistant to the venom.

Among marine animals, eels are resistant to sea snake venoms, which contain complex mixtures of neurotoxins, myotoxins, and nephrotoxins, varying according to species.^[63][64] Eels are especially resistant to the venom of sea snakes that specialise in feeding on them, implying coevolution; non-prey fishes have little resistance to sea snake venom.^[65]

Clownfish always live among the tentacles of venomous sea anemones (an obligatory symbiosis for the fish),^[66] and are resistant to their venom.^[67][68] Only 10 known species of anemones are hosts to clownfish and only certain pairs of anemones and clownfish are compatible.^[69][70] All sea anemones produce venoms delivered through discharging nematocysts and mucous secretions. The toxins are composed of peptides and proteins. They are used to acquire prey and to deter predators by causing pain, loss of muscular coordination, and tissue damage. Clownfish have a protective mucus that acts as a chemical camouflage or macromolecular mimicry preventing "not self" recognition by the sea anemone and nematocyst discharge.^[71][72][73] Clownfish may acclimate their mucus to resemble that of a specific species of sea anemone.^[73]

See also

• Schmidt Sting Pain Index

References

1. "" at Dorland's Medical Dictionary
2. Gupta, Ramesh C. (24 March 2017). Reproductive and developmental toxicology. Saint Louis. pp. 963–972. ISBN 978-0-12-804240-3. OCLC 980850276.{{cite book}}: CS1 maint: location missing publisher (link)
3. Chippaux, JP; Goyffon, M (2006). "[Venomous and poisonous animals--I. Overview]". Médecine Tropicale (in French). 66 (3): 215–20. ISSN 0025-682X. PMID 16924809.
4. "Poison vs. Venom". Australian Academy of Science. 3 November 2017. Retrieved 17 April 2022.
5. Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi: 10.1111/brv.12062. PMID: 24102715.
6. Kordiš, D.; Gubenšek, F. (2000). "Adaptive evolution of animal toxin multigene families". Gene. 261 (1): 43–52. doi:10.1016/s0378-1119(00)00490-x. PMID 11164036.
7. Harris, J. B. (September 2004). "Animal poisons and the nervous system: what the neurologist needs to know". Journal of Neurology, Neurosurgery & Psychiatry. 75 (suppl_3): iii40–iii46. doi:10.1136/jnnp.2004.045724. PMC 1765666. PMID 15316044.
8. Raffray, M.; Cohen, G. M. (1997). "Apoptosis and necrosis in toxicology: a continuum or distinct modes of cell death?". Pharmacology & Therapeutics. 75 (3): 153–177. doi:10.1016/s0163-7258(97)00037-5. PMID 9504137.
9. Dutertre, Sébastien; Lewis, Richard J. (2006). "Toxin insights into nicotinic acetylcholine receptors". Biochemical Pharmacology. 72 (6): 661–670. doi:10.1016/j.bcp.2006.03.027. PMID 16716265.
10. Nicastro, G. (May 2003). Franzoni, L.; de Chiara, C.; Mancin, A. C.; Giglio, J. R.; Spisni, A. "Solution structure of crotamine, a Na+ channel affecting toxin from Crotalus durissus terrificus venom". Eur. J. Biochem. 270 (9): 1969–1979. doi:10.1046/j.1432-1033.2003.03563.x. PMID 12709056. S2CID 20601072.
11. Griffin, P. R.; Aird, S. D. (1990). "A new small myotoxin from the venom of the prairie rattlesnake (Crotalus viridis viridis)". FEBS Letters. 274 (1): 43–47. doi:10.1016/0014-5793(90)81325-I. PMID 2253781. S2CID 45019479.
12. Samejima, Y.; Aoki, Y.; Mebs, D. (1991). "Amino acid sequence of a myotoxin from venom of the eastern diamondback rattlesnake (Crotalus adamanteus)". Toxicon. 29 (4): 461–468. doi:10.1016/0041-0101(91)90020-r. PMID 1862521.
13. Whittington, C. M.; Papenfuss, A. T.; Bansal, P.; et al. (June 2008). "Defensins and the convergent evolution of platypus and reptile venom genes". Genome Research. 18 (6): 986–094. doi:10.1101/gr.7149808. PMC 2413166. PMID 18463304.
14. Sobral, Filipa; Sampaio, Andreia; Falcão, Soraia; et al. (2016). "Chemical characterization, antioxidant, anti-inflammatory and cytotoxic properties of bee venom collected in Northeast Portugal" (PDF). Food and Chemical Toxicology. 94: 172–177. doi:10.1016/j.fct.2016.06.008. hdl:10198/13492. PMID 27288930. S2CID 21796492.
15. Peng, Xiaozhen; Dai, Zhipan; Lei, Qian; et al. (April 2017). "Cytotoxic and apoptotic activities of black widow spiderling extract against HeLa cells". Experimental and Therapeutic Medicine. 13 (6): 3267–3274. doi:10.3892/etm.2017.4391. PMC 5450530. PMID 28587399.
16. Post Downing, Jeanne (1983). "Venom: Source of a Sex Pheromone in the Social Wasp Polistes fuscatus (Hymenoptera: Vespidae)". Journal of Chemical Ecology. 9 (2): 259–266. doi:10.1007/bf00988043. PMID 24407344. S2CID 32612635.
17. Post Downing, Jeanne (1984). "Alarm response to venom by social wasps Polistes exclamans and P. fuscatus". Journal of Chemical Ecology. 10 (10): 1425–1433. doi:10.1007/BF00990313. PMID 24318343. S2CID 38398672.
18. Baracchi, David (January 2012). "From individual to collective immunity: The role of the venom as antimicrobial agent in the Stenogastrinae wasp societies". Journal of Insect Physiology. 58 (1): 188–193. doi:10.1016/j.jinsphys.2011.11.007. hdl:2158/790328. PMID 22108024. S2CID 206185438.
19. Pinto, Antônio F. M.; Berger, Markus; Reck, José; Terra, Renata M. S.; Guimarães, Jorge A. (15 December 2010). "Lonomia obliqua venom: In vivo effects and molecular aspects associated with the hemorrhagic syndrome". Toxicon. 56 (7): 1103–1112. doi:10.1016/j.toxicon.2010.01.013. PMID 20114060.
20. Touchard, Axel; Aili, Samira; Fox, Eduardo; et al. (20 January 2016). "The Biochemical Toxin Arsenal from Ant Venoms". Toxins. 8 (1): 30. doi:10.3390/toxins8010030. ISSN 2072-6651. PMC 4728552. PMID 26805882.
21. Graystock, Peter; Hughes, William O. H. (2011). "Disease resistance in a weaver ant, Polyrhachis dives, and the role of antibiotic-producing glands". Behavioral Ecology and Sociobiology. 65 (12): 2319–2327. doi:10.1007/s00265-011-1242-y. S2CID 23234351.
22. Frost, Emily (30 August 2013). "What's Behind That Jellyfish Sting?". Smithsonian. Retrieved 30 September 2018.
23. Bonamonte, Domenico; Angelini, Gianni (2016). Aquatic Dermatology: Biotic, Chemical and Physical Agents. Springer International. pp. 54–56. ISBN 978-3-319-40615-2.
24. Gallagher, Scott A. (2 August 2017). "Echinoderm Envenomation". EMedicine. Retrieved 12 October 2010.
25. Olivera, B. M.; Teichert, R. W. (2007). "Diversity of the neurotoxic Conus peptides: a model for concerted pharmacological discovery". Molecular Interventions. 7 (5): 251–260. doi:10.1124/mi.7.5.7. PMID 17932414.
26. Barry, Carolyn (17 April 2009). "All Octopuses Are Venomous, Study Says". National Geographic. Retrieved 30 September 2018.
27. Smith, William Leo; Wheeler, Ward C. (2006). "Venom Evolution Widespread in Fishes: A Phylogenetic Road Map for the Bioprospecting of Piscine Venoms". Journal of Heredity. 97 (3): 206–217. doi:10.1093/jhered/esj034. PMID 16740627.
28. Venomous Amphibians (Page 1) – Reptiles (Including Dinosaurs) and Amphibians – Ask a Biologist Q&A. Askabiologist.org.uk. Retrieved on 2013-07-17.
29. Nowak, R. T.; Brodie, E. D. (1978). "Rib Penetration and Associated Antipredator Adaptations in the Salamander Pleurodeles waltl (Salamandridae)". Copeia. 1978 (3): 424–429. doi:10.2307/1443606. JSTOR 1443606.
30. Jared, Carlos; Mailho-Fontana, Pedro Luiz; Antoniazzi, Marta Maria; et al. (17 August 2015). "Venomous Frogs Use Heads as Weapons". Current Biology. 25 (16): 2166–2170. doi:10.1016/j.cub.2015.06.061. ISSN 0960-9822. PMID 26255851. S2CID 13606620.
31. Bauchot, Roland (1994). Snakes: A Natural History. Sterling. pp. 194–209. ISBN 978-1-4027-3181-5.
32. "Snake Bites". A. D. A. M. Inc. 16 October 2017. Retrieved 30 September 2018.
33. Hargreaves, Adam D.; Swain, Martin T.; Hegarty, Matthew J.; Logan, Darren W.; Mulley, John F. (30 July 2014). "Restriction and Recruitment—Gene Duplication and the Origin and Evolution of Snake Venom Toxins". Genome Biology and Evolution. 6 (8): 2088–2095. doi:10.1093/gbe/evu166. PMC 4231632. PMID 25079342.
34. Daltry, Jennifer C.; Wuester, Wolfgang; Thorpe, Roger S. (1996). "Diet and snake venom evolution". Nature. 379 (6565): 537–540. Bibcode:1996Natur.379..537D. doi:10.1038/379537a0. PMID 8596631. S2CID 4286612.
35. Cantrell, F. L. (2003). "Envenomation by the Mexican beaded lizard: a case report". Journal of Toxicology. Clinical Toxicology. 41 (3): 241–244. doi:10.1081/CLT-120021105. PMID 12807305. S2CID 24722441.
36. Mullin, Emily (29 November 2015). "Animal Venom Database Could Be Boon To Drug Development". Forbes. Retrieved 30 September 2018.
37. Fry, B. G.; Wroe, S.; Teeuwisse, W. (June 2009). "A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus". PNAS. 106 (22): 8969–8974. Bibcode:2009PNAS..106.8969F. doi:10.1073/pnas.0810883106. PMC 2690028. PMID 19451641.
38. Fry, B. G.; Wuster, W.; Ramjan, S. F. R.; Jackson, T.; Martelli, P.; Kini, R. M. 2003c. Analysis of Colubroidea snake venoms by liquid chromatography with mass spectrometry: Evolutionary and toxinological implications. Rapid Communications in Mass Spectrometry 17:2047-2062.
39. Fry, B. G.; Vidal, N.; Norman, J. A.; et al. (February 2006). "Early evolution of the venom system in lizards and snakes". Nature. 439 (7076): 584–588. Bibcode:2006Natur.439..584F. doi:10.1038/nature04328. PMID 16292255. S2CID 4386245.
40. Benoit, J.; Norton, L. A.; Manger, P. R.; Rubidge, B. S. (2017). "Reappraisal of the envenoming capacity of Euchambersia mirabilis (Therapsida, Therocephalia) using μCT-scanning techniques". PLOS ONE. 12 (2): e0172047. Bibcode:2017PLoSO..1272047B. doi:10.1371/journal.pone.0172047. PMC 5302418. PMID 28187210.
41. Nekaris, K. Anne-Isola; Moore, Richard S.; Rode, E. Johanna; Fry, Bryan G. (27 September 2013). "Mad, bad and dangerous to know: the biochemistry, ecology and evolution of slow loris venom". Journal of Venomous Animals and Toxins Including Tropical Diseases. 19 (1): 21. doi:10.1186/1678-9199-19-21. PMC 3852360. PMID 24074353.
42. Ligabue-Braun, R.; Verli, H.; Carlini, C. R. (2012). "Venomous mammals: a review". Toxicon. 59 (7–8): 680–695. doi:10.1016/j.toxicon.2012.02.012. PMID 22410495.
43. Jørn H. Hurum, Zhe-Xi Luo, and Zofia Kielan-Jaworowska, Were mammals originally venomous?, Acta Palaeontologica Polonica 51 (1), 2006: 1-11
44. Wong, E. S.; Belov, K. (2012). "Venom evolution through gene duplications". Gene. 496 (1): 1–7. doi:10.1016/j.gene.2012.01.009. PMID 22285376.
45. GBD 2013 Mortality and Causes of Death Collaborators (17 December 2014). "Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013". Lancet. 385 (9963): 117–171. doi:10.1016/S0140-6736(14)61682-2. PMC 4340604. PMID 25530442.
46. Pal, S. K.; Gomes, A.; Dasgupta, S. C.; Gomes, A. (2002). "Snake venom as therapeutic agents: from toxin to drug development". Indian Journal of Experimental Biology. 40 (12): 1353–1358. PMID 12974396.
47. Holland, Jennifer S. (February 2013). "The Bite That Heals". National Geographic. Retrieved 30 September 2018.
48. Fox, Eduardo G.P.; Xu, Meng; Wang, Lei; Chen, Li; Lu, Yong-Yue (May 2018). "Speedy milking of fresh venom from aculeate hymenopterans". Toxicon. 146: 120–123. doi:10.1016/j.toxicon.2018.02.050. PMID 29510162.
49. Fox, Eduardo Gonçalves Paterson (2021). "Venom Toxins of Fire Ants". In Gopalakrishnakone, P.; Calvete, Juan J. (eds.). Venom Genomics and Proteomics. Springer Netherlands. pp. 149–167. doi:10.1007/978-94-007-6416-3_38. ISBN 9789400766495.
50. Calvete, Juan J. (December 2013). "Snake venomics: From the inventory of toxins to biology". Toxicon. 75: 44–62. doi:10.1016/j.toxicon.2013.03.020. ISSN 0041-0101. PMID 23578513.
51. Arbuckle, Kevin; Rodríguez de la Vega, Ricardo C.; Casewell, Nicholas R. (December 2017). "Coevolution takes the sting out of it: Evolutionary biology and mechanisms of toxin resistance in animals" (PDF). Toxicon. 140: 118–131. doi:10.1016/j.toxicon.2017.10.026. PMID 29111116. S2CID 11196041.
52. Dawkins, Richard; Krebs, John Richard; Maynard Smith, J.; Holliday, Robin (21 September 1979). "Arms races between and within species". Proceedings of the Royal Society of London. Series B. Biological Sciences. 205 (1161): 489–511. Bibcode:1979RSPSB.205..489D. doi:10.1098/rspb.1979.0081. PMID 42057. S2CID 9695900.
53. McCabe, Thomas M.; Mackessy, Stephen P. (2015). Gopalakrishnakone, P.; Malhotra, Anita (eds.). Evolution of Resistance to Toxins in Prey. pp. 1–19. doi:10.1007/978-94-007-6727-0_6-1. ISBN 978-94-007-6727-0. {{cite book}}: |work= ignored (help)
54. Nuismer, Scott L.; Ridenhour, Benjamin J.; Oswald, Benjamin P. (2007). "Antagonistic Coevolution Mediated by Phenotypic Differences Between Quantitative Traits". Evolution. 61 (8): 1823–1834. doi:10.1111/j.1558-5646.2007.00158.x. PMID 17683426. S2CID 24103.
55. Holding, Matthew L.; Drabeck, Danielle H.; Jansa, Sharon A.; Gibbs, H. Lisle (1 November 2016). "Venom Resistance as a Model for Understanding the Molecular Basis of Complex Coevolutionary Adaptations". Integrative and Comparative Biology. 56 (5): 1032–1043. doi:10.1093/icb/icw082. ISSN 1540-7063. PMID 27444525.
56. Calvete, Juan J. (1 March 2017). "Venomics: integrative venom proteomics and beyond". Biochemical Journal. 474 (5): 611–634. doi:10.1042/BCJ20160577. ISSN 0264-6021. PMID 28219972.
57. Morgenstern, David; King, Glenn F. (1 March 2013). "The venom optimization hypothesis revisited". Toxicon. 63: 120–128. doi:10.1016/j.toxicon.2012.11.022. PMID 23266311.
58. Poran, Naomie S.; Coss, Richard G.; Benjamini, Eli (1 January 1987). "Resistance of California ground squirrels (Spermophilus Beecheyi) to the venom of the northern Pacific rattlesnake (Crotalus Viridis Oreganus): A study of adaptive variation". Toxicon. 25 (7): 767–777. doi:10.1016/0041-0101(87)90127-9. ISSN 0041-0101. PMID 3672545.
59. Coss, Richard G.; Poran, Naomie S.; Gusé, Kevin L.; Smith, David G. (1 January 1993). "Development of Antisnake Defenses in California Ground Squirrels (Spermophilus Beecheyi): II. Microevolutionary Effects of Relaxed Selection From Rattlesnakes". Behaviour. 124 (1–2): 137–162. doi:10.1163/156853993X00542. ISSN 0005-7959.
60. Holding, Matthew L.; Biardi, James E.; Gibbs, H. Lisle (27 April 2016). "Coevolution of venom function and venom resistance in a rattlesnake predator and its squirrel prey". Proceedings of the Royal Society B: Biological Sciences. 283 (1829): 20152841. doi:10.1098/rspb.2015.2841. PMC 4855376. PMID 27122552.
61. Conant, Roger (1975). A field guide to reptiles and amphibians of Eastern and Central North America (Second ed.). Boston: Houghton Mifflin. ISBN 0-395-19979-4. OCLC 1423604.
62. Weinstein, Scott A.; DeWitt, Clement F.; Smith, Leonard A. (December 1992). "Variability of Venom-Neutralizing Properties of Serum from Snakes of the Colubrid Genus Lampropeltis". Journal of Herpetology. 26 (4): 452. doi:10.2307/1565123. JSTOR 1565123. S2CID 53706054.
63. Heatwole, Harold; Poran, Naomie S. (15 February 1995). "Resistances of Sympatric and Allopatric Eels to Sea Snake Venoms". Copeia. 1995 (1): 136. doi:10.2307/1446808. JSTOR 1446808.
64. Heatwole, Harold; Powell, Judy (May 1998). "Resistance of eels (Gymnothorax) to the venom of sea kraits (Laticauda colubrina): a test of coevolution". Toxicon. 36 (4): 619–625. doi:10.1016/S0041-0101(97)00081-0. PMID 9643474.
65. Zimmerman, K. D.; Heatwole, Harold; Davies, H. I. (1 March 1992). "Survival times and resistance to sea snake (Aipysurus laevis) venom by five species of prey fish". Toxicon. 30 (3): 259–264. doi:10.1016/0041-0101(92)90868-6. ISSN 0041-0101. PMID 1529461.
66. Litsios, Glenn; Sims, Carrie A.; Wüest, Rafael O.; Pearman, Peter B.; Zimmermann, Niklaus E.; Salamin, Nicolas (2 November 2012). "Mutualism with sea anemones triggered the adaptive radiation of clownfishes". BMC Evolutionary Biology. 12 (1): 212. doi:10.1186/1471-2148-12-212. ISSN 1471-2148. PMC 3532366. PMID 23122007.
67. Fautin, Daphne G. (1991). "The anemonefish symbiosis: what is known and what is not". Symbiosis. 10: 23–46 – via University of Kansas.
68. Mebs, Dietrich (15 December 2009). "Chemical biology of the mutualistic relationships of sea anemones with fish and crustaceans". Toxicon. Cnidarian Toxins and Venoms. 54 (8): 1071–1074. doi:10.1016/j.toxicon.2009.02.027. ISSN 0041-0101. PMID 19268681.
69. da Silva, Karen Burke; Nedosyko, Anita (2016), Goffredo, Stefano; Dubinsky, Zvy (eds.), "Sea Anemones and Anemonefish: A Match Made in Heaven", The Cnidaria, Past, Present and Future: The world of Medusa and her sisters, Springer International Publishing, pp. 425–438, doi:10.1007/978-3-319-31305-4_27, ISBN 978-3-319-31305-4
70. Nedosyko, Anita M.; Young, Jeanne E.; Edwards, John W.; Silva, Karen Burke da (30 May 2014). "Searching for a Toxic Key to Unlock the Mystery of Anemonefish and Anemone Symbiosis". PLOS ONE. 9 (5): e98449. Bibcode:2014PLoSO...998449N. doi:10.1371/journal.pone.0098449. ISSN 1932-6203. PMC 4039484. PMID 24878777.
71. Mebs, D. (1 September 1994). "Anemonefish symbiosis: Vulnerability and resistance of fish to the toxin of the sea anemone". Toxicon. 32 (9): 1059–1068. doi:10.1016/0041-0101(94)90390-5. ISSN 0041-0101. PMID 7801342.
72. Lubbock, R.; Smith, David Cecil (13 February 1980). "Why are clownfishes not stung by sea anemones?". Proceedings of the Royal Society of London. Series B. Biological Sciences. 207 (1166): 35–61. Bibcode:1980RSPSB.207...35L. doi:10.1098/rspb.1980.0013. S2CID 86114704.
73. Litsios, Glenn; Kostikova, Anna; Salamin, Nicolas (22 November 2014). "Host specialist clownfishes are environmental niche generalists". Proceedings of the Royal Society B: Biological Sciences. 281 (1795): 20133220. doi:10.1098/rspb.2013.3220. PMC 4213602. PMID 25274370.