How the cobra got its flesh-eating venom: Cytotoxicity as a defensive innovation and its co-evolution with hooding, aposematic marking, and spitting

Panagides, Nadya, Jackson, Timothy N.W., Ikonomopoulou, Maria P., Arbuckle, Kevin, Pretzler, Rudolf, Yang, Daryl C., Ali, Syed A., Koludarov, Ivan, Dobson, James, Sanker, Brittany, Asselin, Angelique, Santana, Renan C., Hendrikx, Iwan, van der Ploeg, Harold, Tai-A-Pin, Jeremie, van den Bergh, Romilly, Kerkkamp, Harald M.I., Vonk, Freek J., Naude, Arno, Strydom, Morné A., Jacobsz, Louis, Dunstan, Nathan, Jaeger, Marc, Hodgson, Wayne C., Miles, John and Fry, Bryan G. (2017) How the cobra got its flesh-eating venom: Cytotoxicity as a defensive innovation and its co-evolution with hooding, aposematic marking, and spitting. Toxins, 9 103: . doi:10.3390/toxins9030103

Attached Files (Some files may be inaccessible until you login with your UQ eSpace credentials)
Name Description MIMEType Size Downloads
UQ510479_OA.pdf Full text (open access) application/pdf 13.29MB 0

Author Panagides, Nadya
Jackson, Timothy N.W.
Ikonomopoulou, Maria P.
Arbuckle, Kevin
Pretzler, Rudolf
Yang, Daryl C.
Ali, Syed A.
Koludarov, Ivan
Dobson, James
Sanker, Brittany
Asselin, Angelique
Santana, Renan C.
Hendrikx, Iwan
van der Ploeg, Harold
Tai-A-Pin, Jeremie
van den Bergh, Romilly
Kerkkamp, Harald M.I.
Vonk, Freek J.
Naude, Arno
Strydom, Morné A.
Jacobsz, Louis
Dunstan, Nathan
Jaeger, Marc
Hodgson, Wayne C.
Miles, John
Fry, Bryan G.
Title How the cobra got its flesh-eating venom: Cytotoxicity as a defensive innovation and its co-evolution with hooding, aposematic marking, and spitting
Journal name Toxins   Check publisher's open access policy
ISSN 2072-6651
2072-6651
Publication date 2017-03-13
Year available 2017
Sub-type Article (original research)
DOI 10.3390/toxins9030103
Open Access Status DOI
Volume 9
Issue 103
Total pages 22
Place of publication Basel, Switzerland
Publisher M D P I AG
Collection year 2018
Language eng
Formatted abstract
The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras (Ophiophagus). There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja, once within the Asian Naja, and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata, which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e.g., hydrophiine sea snakes). The results of this study make an important contribution to our growing understanding of the selection pressures shaping the evolution of snake venom and its constituent toxins. The data also aid in elucidating the relationship between these selection pressures and the medical impact of human snakebite in the developing world, as cytotoxic cobras cause considerable morbidity including loss-of-function injuries that result in economic and social burdens in the tropics of Asia and sub-Saharan Africa.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Biological Sciences Publications
School of Medicine Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 0 times in Thomson Reuters Web of Science Article
Scopus Citation Count Cited 0 times in Scopus Article
Google Scholar Search Google Scholar
Created: Wed, 15 Mar 2017, 11:38:25 EST by Ms Kate Rowe on behalf of Learning and Research Services (UQ Library)