Purloined Poisons: Sequestered chemical defense in a Japanese snake

Al Savitzky, NSF

April 13, 2009 @ 05:00 pm to 06:00 pm

112 Borland

Although many invertebrates are known to obtain defensive chemicals from toxic dietary items, there are few vertebrate examples of sequestered defenses. The Yamakagashi, an Asian snake, possesses a series of defensive structures known as nuchal glands in the skin of the neck that release steroidal toxins in response to attack by predators. Our work has shown that the toxins delivered by the snake are derived from toads consumed as prey. Snakes from toad-free environments lack defensive toxins, whereas those from toad-rich islands are heavily endowed with such compounds. Furthermore, female snakes are able to transfer toxins to their embryos, allowing their offspring to be chemically defended from the time of hatching. Studies of the uptake, modification, storage, and tolerance of toad toxins by the snake are ongoing. It is likely that additional examples of sequestered toxins remain to be discovered among tetrapod vertebrates.

Contact

Stephanie Lessard-Pilon
sal275@psu.edu