Mimicry Cycles, Traps, and Chains: The Coevolution of Toucan and Kiskadee Mimicry.

Interspecific social dominance mimicry (ISDM) is a form of social parasitism in which a subordinate species evolves to mimic and deceive a dominant interference competitor in order to avoid attack by the dominant species. ISDM has been proposed to result in (1) antagonistic coevolutionary arms races in appearance between the model and the mimic (e.g., Ramphastos toucans) and (2) the evolution of complexes of multiple species converging on a common visual appearance (e.g., kiskadee flycatchers). We present evolutionary games of antagonistic coevolution in appearance between pairs and triplets of sympatric species under interference competition. We identify conditions for the existence and stability of (1) coevolutionary mimicry cycles in appearance between evader and pursuer strategies of models and mimics, (2) mimicry chains in which three or more species are coevolutionarily entrained to evolve a single common appearance despite differences in their costs and benefits, and (3) mimicry traps in which a subdominant species is evolutionarily constrained from evading mimicry by a third, subordinate mimic species. Mimicry cycles will result in the evolutionary divergence of models and mimics from their ancestral phenotypes. The hierarchical evolutionary dynamics of ISDM traps and chains resemble Müllerian mimicry with variable costs to toxicity.

The Hairy-Downy game: a model of interspecific social dominance mimicry.

The evolution of many forms of mimicry are well understood, but the evolution of mimicry in the absence of aposematic models or third party participants remains poorly understood. This paper presents a model of the evolution of interspecific social dominance mimicry (ISDM), that does not rely on third-party observers, in the context of the Hairy-Downy game. Members of a socially dominant species contest a resource by playing the hawk-dove game. Nonmimic members of a subordinate species surrender the resource whenever encountering a member of the dominant species, and split the resource whenever interacting among themselves. Mimicry allows members of the subordinate species to pose as members of the dominant species who play dove, splitting the resource when facing other dominant doves while continuing to surrender the resource to dominant hawks. We characterize the evolutionary dynamics and equilibrium behavior of this game, developing conditions under which evolution will select for mimicry, and under which the subordinate species will consist (almost or even literally) entirely of mimics.

Sex and evolutionary stability.

We study evolutionary games in which the rest points of the evolutionary dynamic cluster in connected components, focusing on what we call the Resource Game as a canonical example. The long-term outcome in such games can depend critically on second-order forces that were excluded from the evolutionary dynamics because they are typically insignificant compared with selection pressures. We show that the influence of second-order forces on long-term outcomes can depend on whether the reproduction underlying the evolutionary dynamics is sexual or asexual. An implication is that care is needed in adopting the convenience of an asexual model when examining the behavior of a sexual population in games with nontrivial components of rest points.