|An adult male Taricha granulosa in breeding condition.|
There is enough tetrodotoxin in this newt to kill you
and about 29 other people.
|Chemical structure of tetrodotoxin|
|Map of gartersnake resistance to tetrodotoxin|
Outside of the range of the Rough-skinned Newt,
gartersnakes have essentially no resistance.
Figure from Brodie Jr. et al 2002
|Three species of TTX-resistant snakes:|
top: Amphiesma pryori
middle: Erythrolamprus epinephelus
bottom: Rhabdophis tigrinus
|Common Gartersnake (Thamnophis sirtalis)|
from Oregon's Willamette Valley, where newt toxicity and
snake resistance are both at their peak
There's much left to discover about this system, which is perhaps one of the most interesting in snake biology. Where are newts getting tetrodotoxin from? How many other times has TTX resistance evolved in snakes, and has it happened the same way every time? To what extent are gartersnakes using newt-derived TTX to protect against their own predators? Someday, we will find out.
Brodie III, E. and E. Brodie Jr. 1999. Costs of exploiting poisonous prey: evolutionary trade-offs in a predator-prey arms race. Evolution 53:626-631 <link>
Geffeney, S., E. Brodie Jr, P. Ruben, and E. Brodie III. 2002. Mechanisms of adaptation in a predator-prey arms race: TTX-resistant sodium channels. Science 297:1336-1339 <link>
Geffeney, S., E. Fujimoto, E. Brodie, and P. Ruben. 2005. Evolutionary diversification of TTX-resistant sodium channels in a predator–prey interaction. Nature 434:759-763 <link>
Hanifin, C. T. and E. D. Brodie Jr. 2008. Phenotypic mismatches reveal escape from arms-race coevolution. PLoS Biology 6:e60 <link>
Feldman, C. R., E. D. Brodie, and M. E. Pfrender. 2012. Constraint shapes convergence in tetrodotoxin-resistant sodium channels of snakes. Proceedings of the National Academy of Sciences 106:13415-13420 <link>
Williams, B. L. and R. L. Caldwell. 2009. Intra-organismal distribution of tetrodotoxin in two species of blue-ringed octopuses (Hapalochlaena fasciata and H. lunulata). Toxicon 54:345-353 <link>
Williams, B. L., E. D. Brodie Jr., and E. 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 30:1901-1919 <link>