Rapid Evolution of Antipredator Responses Do Pacific Treefrog Populations Differ in Their Response to an Introduced Predator? David Paoletti Advisor: Dr. Andrew Blaustein

Loss of Biodiversity Declining globally across all taxa

Amphibian Population Declines Various Factors Contribute: UV radiation Disease Habitat Loss Pollution Over-harvesting Introduced Species Oregon Spotted Frog

Introduced Species Many plant and animal species have become successfully established in foreign environments. Zebra Mussel Himalayan BlackberryCane Toad

Introduced Species Brook Trout (Salvelinus fontinalus) Focal Species Pacific Treefrog (Hyla regilla)

Antipredator Behaviors Most amphibian larvae rely on waterborne chemical cues to detect a potential threat. Upon detection, an individual may respond in several ways: Camouflage Refuge use Decrease in activity

Allopatric vs. Sympatric Populations ALLOPATRY SYMPATRY FrogsFish Frogs+ Fish

Allopatric vs. Sympatric Populations Previous studies have shown that a population may evolve to avoid a newly introduced predator. Kiesecker and Blaustein, 1997

I Thought I Smelled Something… HYPOTHESIS: Allopatric treefrog populations will not exhibit antipredator behaviors. Sympatric treefrog populations will recognize trout as potential predators and thus change their behavior accordingly.

Collection H. regilla egg masses were collected from natural populations in the Cascade Mountains. One from a lake with brook trout (allopatric). One from a trout-free habitat (sympatric).

Susan’s Pond Trout-free habitat Three Creeks Lake Last stocked in 1961

Experimental Design Allopatric Population Sympatric Population Control Group (No chemical cue) Control Group (No chemical cue) Predator Chemical Cue Predator Chemical Cue Alternate Chemical Cue Alternate Chemical Cue

Methods 15 minute acclimation period Individuals spot-checked every ten minutes for two hours and any change in position was recorded

Methods Observations were conducted in a laboratory setting. Activity levels for each group were recorded and analyzed.

Predictions

Movement ANOVA- P<0.001 cue effect P=0.016 pop. effect * Predator cue significantly decreased movement Tadpoles from the allopatric population moved significantly less often

Distance ANOVA- P<0.001 cue effect P=0.05 pop. effect * Both populations decreased distance traveled in the presence of predator cues Tadpoles from the allopatric population traveled less distance

Predicted Results Actual Results

Conclusions Sympatric AND allopatric populations reduce activity in the presence of a predator Treefrog populations exhibit antipredator behaviors in the presence of a perceived threat, regardless of prior experience

Rapid Evolution? No evidence… MetapopulationMetapopulation Ancestral populations previouslyAncestral populations previously exposed to predator exposed to predator

Acknowledgements Howard Hughes Medical Institute and Undergraduate Research, Innovation, Scholarship and Creativity (URISC) Kevin Ahern and Andy Blaustein Blaustein Lab: Dr. Tiffany Garcia Betsy Bancroft Anna Jolles John Romansic Erin Scheessele