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Microgeographic divergence of functional responses among salamanders under antagonistic selection from apex predators

Citation

Urban, Mark C.; Friedenfelds, Nicole; Richardson, Jonathan (2021), Microgeographic divergence of functional responses among salamanders under antagonistic selection from apex predators, Dryad, Dataset, https://doi.org/10.5061/dryad.j0zpc86cd

Abstract

A predator's functional response determines predator–prey interactions by describing the relationship between the number of prey available and the number eaten. Its shape and parameters fundamentally govern the dynamic equilibrium of predator–prey interactions and their joint abundances. Yet, estimates of these key parameters generally assume stasis in space and time and ignore the potential for local adaptation to alter feeding responses and the stability of trophic dynamics. Here, we evaluate if functional responses diverge among populations of spotted salamander ( Ambystoma maculatum ) larvae that face antagonistic selection on feeding strategies based on their own risk of predation. Common garden experiments revealed that spotted salamander from ponds with varying predation risks differed in their functional responses, suggesting an evolutionary response. Applying mechanistic equations, we discovered that the combined changes in attack rates, handling times and shape of the functional response enhanced feeding rate in environments with high densities of gape-limited predators. We suggest how these parameter changes could alter community equilibria and other emergent properties of food webs. Community ecologists might often need to consider how local evolution at fine scales alters key relationships in ways that alter local diversity patterns, food web dynamics, resource gradients and community responses to disturbance.

Methods

We evaluated prey eaten versus prey given in larvae raised in a common garden experiment from different populations.

Usage Notes

Column names: rep - temporal replicate; pred.risk - high or low marbled salamander predation risk in natal pond; cue - with or without chemical cues from marbled salamanders (AMOP); vase - container number; family - sibship number (egg mass); food.given - number of Daphnia provided initially; food.eaten - number of Daphnia eaten after 24 hours; wt - larval wet mass in mg.

Funding

National Science Foundation, Award: DEB-1555876

Division of Environmental Biology, Award: 1555876

Division of Environmental Biology, Award: 1119877