Date of Graduation

Spring 2015


Master of Science in Biology



Committee Chair

Alicia Mathis


Eurycea tynerensis, intraspecific variation, antipredator behavior, sex, reproductive condition, swimming speed, activity, fitness trade-off

Subject Categories



Intrinsic and extrinsic factors interact to create unique selection pressures that influence the behavior of individuals both within and among populations. Intrinsic differences in body size, age, sex, and reproductive status can contribute to behavioral variation among conspecifics. Environmental influences include predation pressure, resource availability, and abiotic variables such as temperature. I examined paedomorphic Oklahoma salamanders (Eurycea tynerensis) from two spatially segregated populations in Missouri and Oklahoma to determine whether antipredator behavior, swimming speed, activity, and proximity to cover were influenced by sex, reproductive condition, or population of origin. The two populations differed in several respects, with individuals from the Missouri population being generally more active (especially during the daytime), with higher swimming speeds (especially males) and shorter latencies to strike at prey. Predation risk was simulated by exposing salamanders to chemical stimuli from a benthic fish predator (Ozark sculpin, Cottus hypselurus). Salamanders from both populations were more likely to swim to the surface and altered their latencies to move following exposure to predatory threat from sculpin. Latency differences were affected by sex; females increased while males decreased latency to move when exposed to threatening stimuli. Non-gravid females from the Oklahoma population showed a lower affinity for cover than either males or gravid females. The behavioral differences between populations and among sex classes likely reflect both intrinsic and extrinsic factors that influence fitness trade-offs between reproduction, foraging, and antipredator behavior.


© Lauren Joyce Rudolph

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