| Summary: | 碩士 === 國立中山大學 === 生物科學系研究所 === 92 === The behavioral and physiological interaction between Bufo bankorensis and its snake predators, Macropisthodon rudis and Dinodon rufozonatum were investigated in this study. Adult M. rudis preferred medium sized toads but neonate favored to small ones. About seized position of different toad sizes, adult snakes attacked large toads head first but neonates did randomly. On the swallow direction with toad sizes, adult snakes had no preference but neonates swallowed large toads head first, so the neonates could change the direction swallowing preys after preys had been seized. Adult and neonate snakes spent similar time in handling toads with head first ingestion costed less handling time. After the large rear-teeth had been grounded, M. rudis would spend more time in handling preys. In all trials, venom secreted from parotid glands did not seem to prolong handling time on adult snake. After forced fed 1 mg/g toad venom to D. rufozonatum, no significant change of Na+, K+, Ca2+ ion concentrations were observed but significant increasing of heart rates. The ECGs of intoxicated snakes showed typical digitalis-like cardioactive effects as sinus arrhythmia, prolonged P-R interval as varying degrees of atrioventricular block and ventricular fibrillation. The LD50 of the venom of B. bankorensis are different between from toads sampled Northern and Southern Taiwan. In comparison with dissected toad-eating snakes D. rufozonatum, M. rudis and Rhabdophis tigrinus formosanus, I didn’t find any nuchal glands on nuchal-dorsal site of D. rufozonatum and M. rudis.
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