Meeting Abstract

12.5  Wednesday, Jan. 4  MIMICRY AND THE PROXIMATE BASIS OF ADAPTATION KIKUCHI, DW*; PFENNIG, DW; Univ. of North Carolina, Chapel Hill; Univ. of North Carolina, Chapel Hill

Mimicry is one of the classical examples of adaptation, yet we have much to learn about how mimetic phenotypes are produced. As an instance of convergent evolution, mimicry is an opportunity to study how different species respond to similar selective pressures. For example, do models and mimics use different developmental pathways to produce their phenotypes? Either alternative would have costs and benefits to mimics. Mimics using the same developmental pathway as their models might be able to produce very good mimicry, but at the same time might pay a pleiotropic or epistatic cost for doing so. Such mutations have also been considered highly unlikely. Alternatively, mimics using a different developmental system from their model would have to assemble their mimetic phenotype from scratch, and might never achieve very good mimicry. I present data showing that a Batesian mimic (the scarlet kingsnake) and its model (the coral snake) use very similar developmental mechanisms to produce the colorful signals that they present to predators. Both use melanin sequestered in melanophores to create black coloration, and both use drosopterin pigments sequestered in erythrophores to produce red coloration. Furthermore, although they obviously differ in the spatial patterning of their color patterns, I show that predators do not exert selection on that aspect of phenotype. This story illustrates how selection can drive mimicry to evolve via parallel mechanisms in some dimensions of phenotype, but other dimensions of what we might expect to constitute mimicry do not evolve in concert.