Do aposematic species have larger range sizes? A case study with neotropical poison frogs

Abstract

Aim: Aposematic animals, i.e., those that are defended and warn potential predators through signals, are suggested to have resource-gathering advantages against non-aposematic ones. We here explore this in a biogeographic framework expecting that aposematic species are better dispersers, which translates into larger geographic range size. Location: South America. Taxon: Poison frogs (Amphibia; Aromobatidae and Dendrobatidae). Methods: We use 43 toxic and 26 non-toxic poison frog species from the lowlands only as representatives of aposematic and non-aposematic study organisms, respectively. Realised and potential geographic ranges are calculated using minimum convex polygon and species distribution modelling methods, respectively. Accounting for species body size and phylogeny, we test if both range and aposematism are correlated using linear mixed-effects models. Results: Aposematic and non-aposematic species neither differ in realised nor in potential geographic range size. There was no effect on body size. Main Conclusions: The role of aposematism is not yet as clear as suggested and determinants of poison frog range sizes are multifaceted. A more integrative approach is needed using the information on behaviour, predation risk, and reproductive biology to assess the role of aposematism on observed species distributions. Such data are not yet available for most species, neither poison frogs nor other aposematic animals.