Meeting Abstract

104.5  Saturday, Jan. 7  Sequestration of Defensive Toxins by the Asian Snake Rhabdophis tigrinus: Effects of Local Prey Availability and Maternal Diet HUTCHINSON, D.A.*; MORI, A.; SAVITZKY, A.H.; BURGHARDT, G.M.; NGUYEN, C.; MEINWALD, J.; SCHROEDER, F.C.; Coastal Carolina University, Conway, SC; Kyoto University, Sakyo, Japan; Utah State University, Logan, UT; University of Tennessee, Knoxville, TN; Coastal Carolina University, Conway, SC; Cornell University, Ithaca, NY; Cornell University, Ithaca, NY

Rhabdophis tigrinus (Colubridae: Natricinae) is an Asian snake that possesses defensive glands known as nuchal glands on the dorsal side of its neck. The fluid from these glands contains bufadienolide steroids, which are cardiotoxic to many predators. Bufadienolides are also found in the skin glands of toads, and presumably individuals from most populations of R. tigrinus consume toads as part of their diet. By performing feeding experiments, we demonstrated previously that R. tigrinus sequesters the defensive bufadienolides in its nuchal glands from consumed toads. Snakes from a toad-free island (Kinkasan, Miyagi Prefecture) were found to lack bufadienolides in their nuchal gland fluid, reflecting the absence of toads in their native habitat. However, when R. tigrinus from Kinkasan were fed toads in captivity, they were able to sequester bufadienolides in their nuchal glands. Hatchling snakes from an island with a dense population of toads (Ishima, Tokushima Prefecture) possessed large quantities of bufadienolides in their nuchal gland fluid. We demonstrated that female R. tigrinus are able to provision bufadienolides to their embryos through deposition of those compounds in yolk and by late-gestational transfer, presumably across shelled eggs. Maternal provisioning explains the presence of bufadienolides in hatchlings from Ishima, and these snakes can sequester additional bufadienolides from toads that they consume after hatching.