Predator induced defense mechanisms of larval Blanchard's cricket frogs (Acris blanchard), and their post-metamorphic effects
by Hall, Taylor Lee, M.S., STEPHEN F. AUSTIN STATE UNIVERSITY, 2010, 100 pages; 1486107

Abstract:

Many anuran species utilize inducible defenses to overcome varying predation risks. In Blanchard's Cricket Frog (Acris blanchardi), fish and invertebrate induced phenotypes are known, but the causes or effects of these phenotypes are poorly understood. I sampled 35 East Texas wetlands for larval cricket frogs, and used landmark-based geometric morphometrics to quantify anti-predator morphologies. I reared 15 sibships of tadpoles, and subsequently exposed them to fish and dragonfly larvae to determine which traits are phenotypically plastic in the presence of these predators. I then investigated whether behavior or morphology enhanced tadpole survival, exposing them to both predators while observing predation rates and activity levels. Finally, I performed jump trials to determine post-metamorphic effects on performance. Distinct anti-predator morphotypes occurred in this species, with some features representing predator specific phenotypically plastic traits. Tadpole activity levels differed amongst predators, but were similar between natal pond types, suggesting that anti-predator behaviors were also plastic. These traits enhanced tadpole survival in the presence of their respective predator. Finally, natal pond predator type influenced post-metamorphic morphologies and jump ability, indicating trade-offs to adopting anti-predator mechanisms in A. blanchardi. These results suggest that larval cricket frogs possess a suite of morphological and behavioral approaches to cope with variable predation pressures. These effects at the larval stage may also impact anti-predator strategies post-metamorphosis.

 
AdviserMatt Kwiatkowski
SchoolSTEPHEN F. AUSTIN STATE UNIVERSITY
SourceMAI/ 49-01, p. , Sep 2010
Source TypeThesis
SubjectsEcology
Publication Number1486107
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