EAPSI: The effects of toxins ingestion on locomotor speed in the snake Rhabdophis tigrinus

Moses Kevin A, Logan UT

Investigators

Abstract

All toads produce a class of toxins known as bufadienolides that have a lethal effect on cardiac muscle in most animals, making them inedible to the majority of species. Rhabdophis tigrinus is a Japanese snake that is resistant to those toxic compounds and stores, or sequesters, the toxins in its own tissues. This unusual adaptation provides this snake with a chemical defense against its own predators. Despite its evolved resistance to the bufadienolide toxins (BDs) of toads, preliminary evidence suggests that R. tigrinus experiences physiological consequences from BDs consumption, including increased heart rate. To date, no well-controlled study has demonstrated experimentally any definitive physiological effects of ingestion of toads by R. tigrinus. In collaboration with Dr. Akira Mori at Kyoto University in Japan, this research will determine the effect of toad toxins on a key measure of physiological performance, locomotor speed. Using a racetrack equipped with infrared timers, this study will measure locomotor speed before and after injection of BDs, along with examining cardiac function and metabolic rate in response to the injection of toad toxins in R. tigrinus. Because there is evidence that R. tigrinus exhibits seasonal shifts in foraging associated with reproductive activity, this research will document the male reproductive cycle and seasonal changes in the size of the adrenal glands using preserved specimens in the collection of the Kyoto University Museum. Finally, reproductive and adrenal tissue samples will be collected for subsequent preparation and microscopic examination. These further studies will shed light on the physiological changes associated with toad eating. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.