EIDIETIS, L; University of Michigan: The affect of wood frog tadpole (Rana sylvatica) plastic morphology on predator (dragonfly nymph, Anax junius) strike behavior

Wood frog tadpoles, Rana sylvatica, show predator induced morphological plasticity correlated with a survival advantage under predation. Predator induced morphology is hypothesized to increase survival by shifting the frequency of predator strikes towards less vital areas of the tadpole body. To test this, tadpoles were raised under no predator cue (NP) and chemical predator cue (PIM) treatments. Laboratory interactions between tadpoles and predatory dragonfly nymphs (Anax junius) were video recorded (30 Hz). The position of strikes and whether strikes resulted in mortality were determined. Morphological differences between treatments were quantified with geometric morphometrics. PIM tadpoles were relatively larger, with deeper tail fins with larger lateral profiles. Strike frequency was predicted to differ along the tadpole body axis. This was confirmed, with the majority of the strikes centered on the head and head-tail intersection. There was some indication that this frequency distribution differed between treatments. Strikes at different body positions were predicted to have different probabilities of causing death. This was confirmed, with strikes on the posterior head and head-tail intersection being the most lethal. The distribution of lethality differed between PIM and NP treatments. The sum of lethality over the length of the body was greater for NP than PIM tadpoles, but this difference may best be explained by size differences between the treatments. In sum, PIM morphology may affect the frequency distribution of predator strikes and the distribution of lethality of strikes along the tadpole body axis. However, the magnitude of the PIM survival advantage may better be explained by size differences than morphological plasticity.