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Selection overrides gene flow to break down maladaptive mimicry


Predators typically avoid dangerous species, and batesian mimicry evolves when a palatable species (the ‘mimic’) co-opts a warning signal from a dangerous species (the ‘model’) and thereby deceives its potential predators1,2. Because predators would not be under selection to avoid the model and any of its look-alikes in areas where the model is absent (that is, allopatry)2,3,4,5, batesian mimics should occur only in sympatry with their model. However, contrary to this expectation, batesian mimics often occur in allopatry6,7,8. Here we focus on one such example—a coral snake mimic3,8. Using indirect DNA-based methods, we provide evidence suggesting that mimics migrate from sympatry, where mimicry is favoured3,9, to allopatry, where it is disfavoured10. Such gene flow is much stronger in nuclear genes than in maternally inherited mitochondrial genes, indicating that dispersal by males may explain the presence of mimetic phenotypes in allopatry. Despite this gene flow, however, individuals from allopatry resemble the model less than do individuals from sympatry. We show that this breakdown of mimicry probably reflects predator-mediated selection acting against individuals expressing the more conspicuous mimetic phenotype in allopatry. Thus, although gene flow may explain why batesian mimics occur in allopatry, natural selection may often override such gene flow and promote the evolution of non-mimetic phenotypes in such areas.

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Figure 1: Gene flow among coral snake mimics.
Figure 2: Breakdown of mimicry.
Figure 3: Summary cladogram of North American Lampropeltis.
Figure 4: Haplotype network for the ‘Northern clade’ of L. t. elapsoides.

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  1. Bates, H. W. Contributions to an insect fauna of the Amazon valley. Lepidoptera: Heliconidae. Trans. Linn. Soc. 23, 495–566 (1862)

    Article  Google Scholar 

  2. Ruxton, G. D., Sherratt, T. N. & Speed, M. P. Avoiding Attack: The Evolutionary Ecology of Crypsis, Warning Signals and Mimicry (Oxford Univ. Press, Oxford, 2004)

    Book  Google Scholar 

  3. Pfennig, D. W., Harcombe, W. R. & Pfennig, K. S. Frequency-dependent Batesian mimicry. Nature 410, 323 (2001)

    Article  CAS  ADS  Google Scholar 

  4. Waldbauer, G. P. & Sternburg, J. G. Experimental field demonstration that two aposematic butterfly color patterns do not confer protection against birds in Northern Michigan. Am. Midl. Nat. 118, 145–152 (1987)

    Article  Google Scholar 

  5. Wallace, A. R. Contributions to the Theory of Natural Selection (Macmillan, London, 1870)

    Google Scholar 

  6. Brower, L. P. & Brower, J. V. Z. The relative abundance of model and mimic butterflies in natural populations of the Battus philenor mimicry complex. Ecology 43, 154–158 (1962)

    Google Scholar 

  7. Clarke, C. & Sheppard, P. M. The genetics of the mimetic butterfly Hypolimnas bolina (L.). Phil. Trans. R. Soc. B 272, 229–265 (1975)

    Article  CAS  ADS  Google Scholar 

  8. Greene, H. W. & McDiarmid, R. Y. Coral snake mimicry: does it occur? Science 213, 1207–1212 (1981)

    Article  CAS  ADS  Google Scholar 

  9. Harper, G. R. & Pfennig, D. W. Mimicry on the edge: why do mimics vary in resemblance to their model is different parts of their geographical range? Proc. R. Soc. Lond. B 274, 1955–1961 (2007)

    Article  Google Scholar 

  10. Pfennig, D. W., Harper, G. R., Brumo, A. F., Harcombe, W. R. & Pfennig, K. S. Population differences in predation on Batesian mimics in allopatry with their model: selection against mimics is strongest when they are common. Behav. Ecol. Sociobiol. 61, 505–511 (2007)

    Article  Google Scholar 

  11. King, R. B. & Lawson, R. Color-pattern variation in Lake Erie water snakes: the role of gene flow. Evolution Int. J. Org. Evolution 49, 885–896 (1995)

    Article  Google Scholar 

  12. Bohonak, A. J. Dispersal, gene flow, and population structure. Q. Rev. Biol. 74, 21–45 (1999)

    Article  CAS  Google Scholar 

  13. Brodie, E. D. & Brodie, E. D. in The Venomous Reptiles of the Western Hemisphere (eds Campbell, J. A. & Lamar, W. W.) Vol. II 617–633 (Comstock Publishing Associates, Ithaca, NY, 2004)

    Google Scholar 

  14. Brodie, E. D. Differential avoidance of coral snake banded patterns by free-ranging avian predators in Costa Rica. Evolution Int. J. Org. Evolution 47, 227–235 (1993)

    Article  Google Scholar 

  15. Smith, S. M. Innate recognition of coral snake pattern by a possible avian predator. Science 187, 759–760 (1975)

    Article  CAS  ADS  Google Scholar 

  16. Beerli, P. & Felsenstein, J. Maximum likelihood estimation of migration rates and population numbers of two populations using a coalescent approach. Genetics 152, 763–773 (1999)

    CAS  PubMed  PubMed Central  Google Scholar 

  17. Prugnolle, F. & de Meeus, T. Inferring sex-biased dispersal from population genetic tools: a review. Heredity 88, 161–165 (2002)

    Article  CAS  Google Scholar 

  18. Blouin-Demers, G. & Weatherhead, P. J. Implications of movement patterns for gene flow in black rat snakes (Elaphe obsoleta). Can. J. Zool. 80, 1162–1172 (2002)

    Article  Google Scholar 

  19. Keogh, J. S., Webb, J. K. & Shine, R. Spatial genetic analysis and long-term mark–recapture data demonstrate male-biased dispersal in a snake. Biol. Lett. 3, 33–35 (2007)

    Article  Google Scholar 

  20. Clobert, J., Danchin, E. & Dhondt, A. A. (eds) Dispersal (Oxford Univ. Press, Oxford, 2001)

    Google Scholar 

  21. Harper, G. R. Evolution of a Snake Mimicry Complex. PhD thesis, Univ. North Carolina. (2006)

    Google Scholar 

  22. Armstrong, M. P., Frymire, D. & Zimmerer, E. J. Analysis of sympatric populations of Lampropeltis triangulum syspila and Lampropeltis triangulum elapsoides, in western Kentucky and adjacent Tennessee with relation to the taxonomic status of the scarlet kingsnake. J. Herpetol. 35, 688–693 (2001)

    Article  Google Scholar 

  23. Palmer, W. M. & Braswell, A. L. Reptiles of North Carolina (Univ. North Carolina Press, Chapel Hill, NC, 1995)

    Google Scholar 

  24. Soltis, D. E., Morris, A. B., McLachlan, J. S., Manos, P. S. & Soltis, P. S. Comparative phylogeography of unglaciated eastern North America. Mol. Ecol. 15, 4261–4293 (2006)

    Article  Google Scholar 

  25. Thompson, J. D., Gibson, T. J., Plewniak, F., Jeanmougin, F. & Higgins, D. G. The ClustalX windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Res. 24, 4876–4882 (1997)

    Article  Google Scholar 

  26. Swofford, D. L. PAUP*. Phylogenetic Analysis Using Parsimony (* and Other Methods) Version 4, 4th edn (Sinauer Associates, Sunderland, MA, 2002)

    Google Scholar 

  27. Ronquist, F. & Huelsenbeck, J. P. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19, 1572–1574 (2003)

    Article  CAS  Google Scholar 

  28. Posada, D. & Crandall, K. A. Modeltest: testing the model of DNA substitution. Bioinformatics 14, 817–818 (1998)

    Article  CAS  Google Scholar 

  29. Clement, M., Posada, D. & Crandall, K. A. TCS: a computer program to estimate gene genealogies. Mol. Ecol. 9, 1657–1660 (2000)

    Article  CAS  Google Scholar 

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We thank the museums and individuals listed in Supplementary Tables 2 and 4 for donating samples for the genetic and colour pattern analyses; M. Landstrom for measuring colour patterns; W. Van Devender for providing photographs in Figs 1a, b and 2a; and K. Pfennig, P. Marko, J. Wiens, A. Rice, R. Martin, C. Ledon-Rettig, J. Kingsolver, M. Servedio and D. Swofford for comments. Funding was provided by the National Science Foundation.

Author Contributions G.R.H. performed the genetic and morphological analyses and helped write the manuscript. D.W.P. designed the study, contributed to the interpretation of the data, and wrote the manuscript.

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Correspondence to David W. Pfennig.

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Harper Jr, G., Pfennig, D. Selection overrides gene flow to break down maladaptive mimicry. Nature 451, 1103–1106 (2008).

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