Search

The behavioural responses of predator-naïve (laboratory-born), predator-experienced (laboratory-born but with short-term experience with predators), and wild-caught (with long-term experience with predators in natural settings) tadpoles of Sphaerotheca breviceps to carnivorous predatory tadpoles of Hoplobatrachus tigerinus was studied in the laboratory. The predator's stimulus solution (kairomones) was used to simulate predation threat. All S. breviceps tadpoles (i.e., predatornaïve, predator-experienced and wild-caught) exhibited behavioural antipredator responses, i.e., reduced swimming activity and time spent swimming, and had a higher burst speed in response to water-borne kairomonal cues of predators. Wildcaught tadpoles showed stronger responses than predator-naïve and predator-experienced tadpoles and the latter exhibited stronger responses than predator-naïve tadpoles. Our study thus suggests that antipredator behaviour in these tadpoles is basically innate. Furthermore, the enhanced antipredator behaviour of wild-caught tadpoles indicates that learning is involved. [ABSTRACT FROM AUTHOR]

Most of the anuran tadpoles spend their early phase of life in aquatic medium. In such system, they respond to a wide variety of stimuli (e.g., tactile, chemical and visual cues) and exhibit appropriate behavioural responses. The ability to detection food and predator was studied in the tadpoles of the bicolored frog, Clinotarsus curtipes in the laboratory by using a rectangular glass test tank with end compartments (stimulus zones) providing exclusively visual and/or chemical food (boiled spinach) or predator (Laccotrephes sp.) cues. A test tadpole, C. curtipes (either starved or fed; Gosner stage 25) was held at the centre of the test tank for 5 min (acclimation) to perceive visual and/or chemical food or predator cues. Then it was released from the centre of the test tank and allowed to associate or stay away from the caged stimulus subjects (food or predator), which were placed at one end of the test tank either in a glass beaker (visual cues) or in a mesh cage wrapped with cheese cloth (chemical cues) for a period of 10 min. The test tadpoles were unable to detect both food and predator through visual cues. They spent almost an equal amount of time in the zone housing food or predator in a glass beaker or opposite zone, which was kept empty. However, they detected both food and predator solely through chemical cues. In tests with chemical food cues, they spent a significantly higher period of time (70.42% of total time) near chemical food cues rather than empty or visual food cues. In contrast, in tests with chemical predator cues, they spent the majority of their time (69.32% of total time) away from the chemical predator cues. The findings thus show that C. curtipes tadpoles detect both food and predator solely through chemical cues rather than visual cues. [ABSTRACT FROM AUTHOR]

The majority of the amphibian larvae spend their early life stage in aquatic medium. In such system, they respond to a broad array of stimuli (tactile, chemical and visual cues) and exhibit suitable behavioural responses. The ability of detection of food and predator was studied in the tadpoles of the Indian skipper frog Euphlyctis cyanophlyctis in the laboratory setup by using a rectangular glass test tank with end compartments (stimulus zones) providing exclusively visual and and (or) chemical food (either boiled spinach or tadpoles of Duttaphrynus melanostictus) and predator (tadpoles of Hoplobatrachus tigerinus). A test tadpole E. cyanophlyctis was held at the centre of the test tank for 5 min (acclimation) to perceive visual and (or) chemical food or predator cues. Then it was released from the centre of the test tank and allowed to associate or stay away from the caged stimulus subjects (food or predator), which were placed at one end of the test tank either in a glass beaker (visual cues) or in a mesh cage wrapped with cheese cloth (chemical cues) for a period of 10 min. The test tadpoles failed to detect either food or predator through visual cues. They spent almost an equal amount of time in the zone housing food or predator in a glass beaker as compared to the opposite zone, which was kept empty. However, they detected both food and predator solely through chemical cues. In tests with chemical food cues (either boiled spinach or tadpoles of D. melanostictus), they spent the majority of their time (67.25 % of total time) near chemical food cues rather than empty or visual food cues. In contrast, in tests with chemical predator cues (tadpoles of H. tigerinus), they spent the majority of their time (68.89 % of total time) away from the chemical predator cues. Therefore, the findings show that E. cyanophlyctis tadpoles detect both food and predator through chemical sensory mechanism rather than visual ones. [ABSTRACT FROM AUTHOR]