| Summary: | 碩士 === 國立成功大學 === 生物學系碩博士班 === 92 === Anti-predator responses are important to the survival of animals. The purposes of this study are (1) to compare the behavioral responses of two anuran larvae, Microhyla ornata and Rana limnocharis, to the predator, dragonfly larvae, Neurothemis ramburii vers terminnata, (2) to understand the mechanism that is responsible for the recognition of the predator, and (3) to investigate the strength of the predator’s chemical cue on the behavioral responses of larval M. ornata. Three experiments were conducted for these purposes. The first experiment compared the distribution and activity pattern of the two larval species in the presence or absence of the predator, in order to identify the anti-predatory behaviors. The second experiment examined the distribution and the swimming rate of larval M. ornata when visual cue or chemical cue of the predator was provided. The third experiment reduced the length of the predator’s stay in the water and studied the distribution of larval M. ornata. The results show that M. ornata larvae tend to stay away from the predator and avoid continuous long distance swimming by breaking it into several short activity bouts and reducing swimming rate in the presence of the predator. Microhyla ornata larvae increase the length of activity time to compensate for the reduced swimming rate, so that the total distance traveled by the larvae remain unchanged. However, larvae of R. limnocharis do not show such responses in the presence of the predator. Microhyla ornata larvae recognize the predators by the predator’s chemical cues. When the chemical cues are not strong enough, larvae of M. ornata do not avoid the predators.
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