Citation

Maan ME, Cummings ME. Am. Nat. 2012; 179(1): E1-E14.

Affiliation

University of Groningen, Behavioural Biology, Nijenborgh 7, 9747 AG Groningen, The Netherlands; University of Bern, Institute of Ecology and Evolution, Baltzerstrasse 6, CH-3012 Bern, Switzerland; and Eawag Centre of Ecology, Evolution and Biogeochemistry (CEEB), Seestrasse 79, CH-6047 Kastanienbaum, Switzerland.

Copyright

(Copyright © 2012, University of Chicago Press)

DOI

10.1086/663197

PMID

22173468

Abstract

Antipredator defenses and warning signals typically evolve in concert. However, the extensive variation across taxa in both these components of predator deterrence and the relationship between them are poorly understood. Here we test whether there is a predictive relationship between visual conspicuousness and toxicity levels across 10 populations of the color-polymorphic strawberry poison frog, Dendrobates pumilio. Using a mouse-based toxicity assay, we find extreme variation in toxicity between frog populations. This variation is significantly positively correlated with frog coloration brightness, a viewer-independent measure of visual conspicuousness (i.e., total reflectance flux). We also examine conspicuousness from the view of three potential predator taxa, as well as conspecific frogs, using taxon-specific visual detection models and three natural background substrates. We find very strong positive relationships between frog toxicity and conspicuousness for bird-specific perceptual models. Weaker but still positive correlations are found for crab and D. pumilio conspecific visual perception, while frog coloration as viewed by snakes is not related to toxicity. These results suggest that poison frog colors can be honest signals of prey unpalatability to predators and that birds in particular may exert selection on aposematic signal design.

Language: en