The behavioral response of larval coastal giant salamanders, Dicamptodon tenebrosus, to chemical stimuli

Nearly all animals are able to detect forms of chemical stimuli. In amphibians, chemoreceptive capabilities are used in a wide variety of contexts, including the detection of predators, conspecifics, and food. The focus of this project was the use of chemoreception in the feeding behavior of larval coastal giant salamanders, Dicamptodon tenebrosus. I investigated natural chemical cues used by larval salamanders to detect, locate, and assess potential food sources in a laboratory setting. Stimuli used in this study were as follows: bologna, agar blank, guano, lipid component of California black worms (Lumbriculus variegatus), cod liver oil, salt, and whole California black worms (Lumbriculus variegatus). All stimuli were housed in an agar-based morsel and presented to test subjects at the end of one arm in a Y-shaped test station. The results of this study provide substantial evidence of coastal giant larvae using chemical cues to detect, assess, and locate a food source. Test subjects actively investigated the test station during trials with all stimuli. All five steps in salamander feeding behavior were observed: orientation, approach, olfactory test, fixation, and snapping. Overall, salamanders showed a general interest in bologna and whole worm morsels. The specific chemical cues used to assess each stimulus were not determined.