UNIT XVPoisonous and Venomous

Vertebrates

Ecological role of toxins

Toxin

Definition

an antigenic poison or venom ofplant or animal origin, esp. oneproduced by or derived frommicroorganisms and causingdisease when present at lowconcentration in the body.

in Oxford American dictionaries

Ecological role of toxins1. Interactions with predators

a. Defense at close contact

b. “Remote” defense

2. Interactions with prey

3. Interactions with competitors

4. Protection against fungi and bacteria

1a.

1b. 2. 3.

Poisonous or Venomous?

Poisonous– producing poison as a means of attacking enemiesor prey: toxic substances which are absorbed through epitheliallinings such as the skin or gut.

Venomous– secreting venom; capable of injecting venom bymeans of a bite or sting.

in Oxford American dictionariesGaboon viper

Poisonous dart frog

Vertebrates

There are around 40,000 species ofvertebrates and around 2,000 are venomous.

Fish

FishThere are 28,000 species of bony fish , and around 1,200 are venomous.

There is large diversity in the traumatizingapparatus:

Venomous spines

Dorsal spines

Opercular spines

Venomous fangs

Echiichthys vipera

Meiacanthus atrodorsalis

Presence of a compoundbuccal gland in the blennyis a new organ for teleostfishes.

This gland has a toxicsecretion that can beinjected into the "victim"through specializedfangs

Blenny FangsMeiacanthus nigrolineatus

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Meiacanthus grammistes

Meiacanthus nigrolineatus

Predator reaction to ingestion of a M.atrodorsalis ?

Predation Protection in the Poison-Fang Blenny, Meiacanthus atrodorsalis, and Its Mimics, Ecsenius bicolor and Runula laudandus

(Blenniidae) GEORGE S. LOSEY

PACIFIC SCIENCE, Volume 26, April 1972

Role of venomous canines of Meiacanthus atrodorsalis ?

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Feeding experiments with Poison-Fang Blenny and its

mimics

Reaction to ingestion:Violent quivering of the head withdistension of the jaws andoperculi. The fish frequentlyremained in this distended

posture for several secondsuntil the M. atrodorsalis emergedfrom their mouth.

Amphibians

Amphibians

There are several species of poisonous amphibians. These include:

• Anura

(e.g. Bufos marinus

and Phyllobates terribilis)

• Caudata (e.g. terrestrial phase of Notophthalmys viridescens and Triturus marmoratus)

Taricha granulosa

• The rough-skin newt possesses high levels of the neurotoxin tetrodotoxin (TTX) in its skin;

• Tetrodotoxin serves as a defensive compound in adult newts;

Toxin is concentrated in the granular glands of the skin

It is also present in other tissues, including ovaries, ova, and eggs;

• What is the TTX toxicity of individual T. granulosa eggs witha known “family structure,” (i.e., from clutches for which thefemale toxicity is known)?

• What is the origin of the TTX in the eggs?

TETRODOTOXIN LEVELS IN EGGS OF THE ROUGH-SKIN NEWT, Taricha granulosa, ARE CORRELATED WITH

FEMALE TOXICITYCHARLES T. HANIFIN;EDMUND D. BRODIE III, and EDMUND D. BRODIE JR.

Journal of Chemical Ecology, Vol. 29, No. 8, August 2003

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TETRODOTOXIN LEVELS IN EGGS OF THE ROUGH-SKIN NEWT, Taricha granulosa, ARE CORRELATED WITH

FEMALE TOXICITYCHARLES T. HANIFIN,1;¤ EDMUND D. BRODIE III,2 and EDMUND D. BRODIE JR.1

Journal of Chemical Ecology, Vol. 29, No. 8, August 2003

Graph of egg toxicity versus female toxicity showing a correlation between female toxicity (on the xaxis) and mean egg toxicity per clutch (on the y axis). The regression line: Mean Clutch TTX (MCT)=Female TTX*3968+735 is significant (F1;9 = 8.128; R2=0.48; P=0.019).

Reptiles

ReptilesVenomous reptiles are only found within the order Squamata. Specifically:

• Genus Heloderma

(Heloderma suspectum

and Heloderma horridum)

• Snakes (Elapidae, Hydrophiidae, Viperidae, Crotalidae)

There are around 2000 species of snakes (2900)

Around 400 species are venomous (725)

What about poisonous snakes?

Rhabdophis tigrinus

Dietary sequestration of defensive steroids in nuchalglands of the Asian snake Rhabdophis tigrinus

Deborah A. Hutchinson, Akira Mori, Alan H. Savitzky, Gordon M. Burghardt, Xiaogang Wu, Jerrold Meinwald, and Frank C. Schroeder

PNAS February 13, 2007 vol. 104 no.7

Japanese snake that occurs in small japanese islands and in the main island of japan.

Behavioral observations showed that Snakes on Japanese islands with a plentiful toad population would arch their neck and display their toxic neck glands when a predator as present, but those on toad-free islands the snakes usually fled.

What is the origin of the toxin in the neck glands?

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Feeding experimentBufo sp.Rhabdophis tigrinus

Another Poisonous snake….

Thamnophis sirtalis - Gartersnakes

• Feed upon the Rough-skinned Newt (Taricha granulosa)• TTX can stay in the liver for 1 month or more after consuming justone newt• The poison can stay at least 7 weeks after consuming a diet of newts.• This amount could be lethal to the birds and mammals that prey uponGartersnakes.

Birds

Ifrita kowaldi

Pitohui dichrous

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• Birds feed on a variety of insects of the same size and evenfrom the same Genus as Choresine beetles

• Choresine beetles are potentially a direct source ofbatrachotoxins for toxic New Guinea birds

Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and

toxic passerine birdsJohn P. Dumbacher, Avit Wako, Scott R. Derrickson, Allan Samuelson, Thomas F.

Spande , and John W. DalyPNAS November 9, 2004 vol. 101 no. 45

Mammals

Ornithorhynchus anatinus

•Crural gland only secretes venom in breeding season

• The use of the venom apparatus is probably related to combat with other males for territory or females.

• The venom apparatus isonly present in males

Slow Loris

Nycticebus coucang

• They have a brachial organ, a naked, gland-laden area of skin on surface of the arm that is licked during grooming.

Venomous and Poisonous Primate?

Nycticebus coucang

Nycticebus coucang inhabits the rainforests of southeast Asia, Assam, Burma, Thailand, Indo-China, certain Malayan states and East Indian Islands.

• When mixed with saliva, the toxin can repel some predators.

• Anaphylaxis has been observed following loris bites.

• N. coucang brachial organ protein acts as an allergen.

Glands of lorises

Traumatizing apparatus

• Nycticebus cougans may alsouse biting as a way ofdelivering the toxin.

• They use the toothcomb toinject the poisonous saliva.

The End

References

1. Smith, William Leo and Wheeler, Ward C. 2006. Venom evolution widespread in fishes: a phylogenetic road map for the bioprospecting of piscine venoms.2006. Journal of Heredity 97(3:206-217

2. Bücherl, Buckley,Deulofeu.Venomous Animals and Their venoms. 1968. Academic Press3. G. G. Habermehl. Venomous Animals and their toxins. 1981. Springer-verlag4. GEORGE S. LOSEY. 1972.Predation Protection in the Poison-Fang Blenny, Meiacanthus atrodorsalis, and Its Mimics, Ecsenius

bicolor and Runula laudandus (Blenniidae). PACIFIC SCIENCE, Volume 265. Sindhu Radhakrishna & Mewa Singh.?.Social Behaviour of the Slender Loris (Loris tardigradus lydekkerianus)?6. William Leo Smith and Ward C. Wheeler. 2006. Venom evolution widespread in fishes: a phylogenetic roda map for the

bioprospecting of piscine venoms. Journal of Heredity 97(3): 206-2177. Charles T. Hanifin, Edmund E. Brodie III, and Edmund D. Brodie Jr.2003. Tetrodotoxin levels in eggs of the rough-skin newt,

Taricha granulosa, are correlated with female toxicity. Journal of Chemical Ecology Vol.29 no88. John P. Dumbacher, Avit Wako, Scott R. Derrickson, Allan Samuelson, Thomas F. Spande , and John W. Daly. 2004. Melyrid

beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds. PNAS vol. 101 no. 45

9. Lev Fishelson. 1974. Histology and ultrastructure of the recently found buccal toxic gland in the fish Meiacanthus nigrolineatus (Belnnidae). Copeia No 2

10. BECKY L. WILLIAMS,EDMUND D. BRODIE, JR., and EDMUND D. BRODIE III . 2004. A RESISTANT PREDATOR AND ITS TOXIC PREY:PERSISTENCE OF NEWT TOXIN LEADS TO POISONOUS (NOT VENOMOUS) SNAKES .Journal of Chemical Ecology, Vol. 30, No. 10

11. Sonja Krane, Yasuhiro Itagaki, Koji Nakanishi,Paul J. Weldon.2003.“Venom” of the slow loris: sequence similarity of prosimian skin gland protein and Fel d 1 cat allergen. Naturwissenschaften (2003) 90:60–62

Websites:1. http://animaldiversity.ummz.umich.edu/site/accounts/information/Nycticebus_coucang.html2. http://www.venomdoc.com/3. http://www.loris-conservation.org/database/disease/1-4_anatomy_skin_glands.html4. http://uts.cc.utexas.edu/~bramblet/ant301/eight.html#anchor10789425. http://www.cosmosmagazine.com/node/14236. http://www.livescience.com/animals/070129_toad_toxin.html7. www.wikipedia.com