Behavioral variation among tadpole populations ecological causes and consequences

Meeting Abstract

90.3  Sunday, Jan. 6  Behavioral variation among tadpole populations: ecological causes and consequences CARLSON, BE*; LANGKILDE, T; The Pennsylvania State University; The Pennsylvania State University

Theory predicts that intraspecific trait variation can have important ecological impacts, yet we have a poor understanding of the causes and consequences of trait variation in natural systems. Local adaptation can generate among-population trait differences, and these adaptive variants may have cascading effects on the rest of the ecosystem through interactions of these organisms with other species. Wood frog tadpoles inhabit ponds that range from ‘low-risk’ (few predators) to ‘high-risk’ (many predators). ‘High-risk’ ponds are expected to favor lower activity levels and greater responsiveness of tadpoles to predator cues than do ‘low-risk’ ponds. We reared tadpoles from a variety of ponds in mesocosms, both with and without caged predators. We measured the behavior of the tadpoles and the predator density in the source ponds. We found that responsiveness to predators increased with predation risk in source ponds while overall activity rate was unaffected. More active tadpoles should have stronger negative effects on periphyton and zooplankton (due to increased foraging), and less responsive tadpoles would result in smaller indirect effects of predators on these lower trophic levels. Preliminary evidence suggests that increased tadpole activity was associated with reductions in periphyton and increases in zooplankton. Behavior in this system varied predictably along an ecological gradient, with apparent consequences for interacting species. This work highlights the potentially important role of ecological differences among communities in shaping, and being reciprocally shaped by, intraspecific behavioral variation.

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