Meeting Abstract

25.3  Wednesday, Jan. 5  The response of Pacific tree frog (Pseudacris regilla) tadpoles to invasive predatory crayfish: a comparison of anti-predator traits between naïve and exposed tadpoles PEASE, K. M.*; WAYNE, R. K.; University of California, Los Angeles; University of California, Los Angeles kpease@ucla.edu

Invasive species are widely recognized as a serious ecological threat; the evolutionary impacts of invasions may be equally as important, yet remain relatively unstudied. Invasive species can promote evolution in native species through novel interactions, including the strong selective force of predation. We examined whether tadpoles of the Pacific tree frog (Pseudacris regilla) are adapting to the invasive predatory red swamp crayfish (Procambarus clarkii). Tadpoles were collected from six study streams in the Santa Monica Mountains, CA (three streams with crayfish and three without crayfish). We analyzed tadpole morphology using geometric and conventional morphometrics. Additionally, we tested anti-predator behavior in the lab using a gravitational flow-through system and performed predation experiments with crayfish. Tadpoles from streams with crayfish were morphologically different from tadpoles from crayfish-free streams in their tail morphologies, indicating possible anti-predator adaptations. Tadpoles from streams with and without crayfish responded behaviorally to crayfish chemical cues by remaining still and swimming less, a common anti-predator behavioral tactic. There was no difference in survival in the predation experiment between tadpoles from streams with and without crayfish. However, there were morphological differences between tadpoles that survived predation and those that were killed or injured. These results indicate that P. regilla tadpoles may be adapting to the presence of the invasive crayfish in both morphology and behavior. The morphological and behavioral differences may allow the tadpoles to coexist and persist with this novel predator.