Behavioral Variation in Response to Predation Risk in a Neotropical Tadpole
Phoebe Reuben ’17, Annie Innes-Gold ’18, Hubert Szczygiel ’18, and Justin Touchon (Biology)
Dendopsophus ebraccatus tadpoles are known to have plastic morphological development when reared in the presence of different predator cues, including differences in tail shape and coloration. Other potential variation, including behavioral modification, has remained unexplored. To address this, we measured the movement of 316 11-day-old tadpoles that had been raised in the presence of chemical cues from dragonfly larvae (Anax amazili) or fish (Astyanax ruberrimus) predation or with predator-free control water. Tadpoles from each rearing environment were tested with each type of cue, creating nine different combinations of rearing environment and testing cue to distinguish the effects of long-term behavioral modification from rapidly induced plastic responses. Tadpole location was recorded in 1.5-minute intervals over 21 minutes and total distance moved was calculated. Tadpoles showed a strong response based on both their rearing environment and their test cue. Tadpoles raised with cues of dragonfly predation moved the least, whereas tadpoles raised with fish cues moved the most. Tadpoles raised with control cues were intermediate, Short-term exposure to cues in the testing environment had similar effects on movement. There was, however, a significant interaction between rearing and test environments such that dragonfly tadpoles did not move less in the presence of the dragonfly cue. Plasticity in behavior appears to occur independently from the previously observed morphological plasticity. This flexibility highlights some potential differences in survival strategy that will be important in understanding both the adaptive significance of the developmental plasticity and the environments that prompt this variation.