Date of Award

Spring 2002

Document Type



Life & Environmental Sciences

First Advisor

Grant Hokit

Second Advisor

John Addis

Third Advisor

Jack Oberweiser


A field experiment was performed to examine the effects of predation on the morphology of the spotted frog (Rana luteiventris). Seven ponds were randomly selected for survey in the Helena National Forest. Macroinvertebrate predators were counted and tadpoles were collected to measure morphological characteristics. Statistical analysis demonstrated that predation had a significant overall effect on tail morphology. Specifically, the higher number of predators in a pond, the longer the tail, the thicker the tail muscle, and the more narrow the mouth width of tadpoles. These induced changes presumably increase swimming speed, improving predator evasion. Interactions with other members of the aquatic community are likely to be influenced as well. This study provides further evidence for predator-induced plasticity in amphibian larvae.