Weak warning signals can persist in the absence of gene flow

Authors

J. P. Lawrence, University of MississippiFollow
Bibiana Rojas, University of Jyväskylä
Antoine Fouquet, Laboratoire Evolution et Diversité Biologique
Johanna Mappes, University of Jyväskylä
Annelise Blanchette, John Carroll University
Ralph A. Saporito, John Carroll University
Renan Janke Bosque, University of Mississippi
Elodie A. Courtois, Laboratoire Ecologie, Evolution, Interactions des Systèmes Amazoniens
Brice Noonan, University of MississippiFollow

Document Type

Article

Publication Date

2019

Abstract

Aposematic organisms couple conspicuous warning signals with a secondary defense to deter predators from attacking. Novel signals of aposematic prey are expected to be selected against due to positive frequency-dependent selection. How, then, can novel phenotypes persist after they arise, and why do so many aposematic species exhibit intrapopulation signal variability? Using a polytypic poison frog (Dendrobates tinctorius), we explored the forces of selection on variable aposematic signals using 2 phenotypically distinct (white, yellow) populations. Contrary to expectations, local phenotype was not always better protected compared to novel phenotypes in either population; in the white population, the novel phenotype evoked greater avoidance in natural predators. Despite having a lower quantity of alkaloids, the skin extracts from yellow frogs provoked higher aversive reactions by birds than white frogs in the laboratory, although both populations differed from controls. Similarly, predators learned to avoid the yellow signal faster than the white signal, and generalized their learned avoidance of yellow but not white. We propose that signals that are easily learned and broadly generalized can protect rare, novel signals, and weak warning signals (i.e., signals with poor efficacy and/or poor defense) can persist when gene flow among populations, as in this case, is limited. This provides a mechanism for the persistence of intrapopulation aposematic variation, a likely precursor to polytypism and driver of speciation.

Relational Format

journal article

Recommended Citation

Lawrence, J.P., B. Rojas, A. Fouquet, J. Mappes, A. Blanchette, R.A. Saporito, R.J. Bosque, E.A. Courtois, B.P. Noonan. Weak warning signals can persist in the absence of gene flow. Proceedings of the National Academy of Sciences. Published Sept. 3, 2019. https://doi.org/10.1073/pnas.1901872116

DOI

10.1073/pnas.1901872116

Previous Versions

Aug 21 2019 (withdrawn)

Accessibility Status

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