Population divergence in Strawberry poison frogs

Photo credits: Andreas Rudh

The likelihood of speciation is assumed to increase if there is divergence in both naturally and sexually selected traits. We study how divergence in coloration and thereby in anti-predation strategies (crypsis versus aposematism) co-vary with divergence in behavior among genetically diverged populations of strawberry poison frogs (Dendrobates pumilio) in north-western Panama. These populations probably became physically isolated as a result of a rise in sea level during the last 10 000 years and therefore provides us with a unique opportunity to study the processes occurring at the early stages of population differentiation. We have suggested that reduced initial population sizes on the islands may have lowered the benefits of using an aposematic strategy and caused selection that favour crypsis despite maintained toxicity and similar predation fauna. The observed variation in colour morph may then simply reflect the fact that conspicuous coloration can be lost in several different ways, i.e. by many different mutations. Shifts between warning and cryptic coloration should in turn influence the evolution of many behavioural traits that are constrained by the risk of predation. 

Selected publications

Rudh, A., Breed, M. F. and Qvarnström, A. 2013. Does aggression and explorative behaviour decrease with lost warning coloration? Biological Journal of the Linnean Society 108: 116-126

Rudh, A., Rogell, B., Håstad, O. and Qvarnström, A. 2011. Rapid population divergence linked with co-variation between coloration and sexual display in strawberry poison frogs. Evolution 65: 1271-1282

Rudh, A., Rogell, B. and Höglund, J. 2007. Non-gradual variation in colour morphs of the strawberry poison frog Dendrobates pumilio: genetic and geographical isolation suggest a role for selection in maintaining polymorphism. Molecular Ecology 16: 4284-4294

Photo credits: Andreas Rudh