Müllerian mimicry in Synodontis
Posted: 02 Oct 2010, 12:24
Wright, J.J. (2010). Conservative co-evolution of Müllerian mimicry in a group of rift lake catfishes. Evolution. DOI:10.1111/j.1558-5646.2010.01149.x
ABSTRACT:
Biological mimicry has long been viewed as a powerful example of natural selection's ability to drive phenotypic evolution, although continuing debates surround the mechanisms leading to its development and the nature of these mimetic relationships. Müllerian mimicry, in which unpalatable species derive a mutual selective benefit through evolved phenotypic similarity, has alternatively been proposed to evolve through either a two-step process initiated by a large mutational change, or through continuous gradual evolution towards a common aposematic phenotype. I exposed a model predatory fish species to two species of endemic Lake Tanganyikan Synodontis to provide evidence for aposematism and the presence of Müllerian mimicry in these species. Predators quickly became conditioned to avoid the venomous catfishes and did not discriminate between the two species when they were switched, supporting a hypothesis of functional Müllerian mimicry in this group of similarly colored fishes. Ancestral state reconstructions and statistical comparisons of color pattern divergence in Tanganyikan Synodontis indicate that Müllerian mimicry in these catfishes has developed through diversification of an aposematic common ancestor with subsequent conservative mutualistic co-evolution among its daughter lineages, rather than advergent evolution of a mimic towards a non-related model, as assumed by widely accepted models of Müllerian mimicry evolution.
Link.
ABSTRACT:
Biological mimicry has long been viewed as a powerful example of natural selection's ability to drive phenotypic evolution, although continuing debates surround the mechanisms leading to its development and the nature of these mimetic relationships. Müllerian mimicry, in which unpalatable species derive a mutual selective benefit through evolved phenotypic similarity, has alternatively been proposed to evolve through either a two-step process initiated by a large mutational change, or through continuous gradual evolution towards a common aposematic phenotype. I exposed a model predatory fish species to two species of endemic Lake Tanganyikan Synodontis to provide evidence for aposematism and the presence of Müllerian mimicry in these species. Predators quickly became conditioned to avoid the venomous catfishes and did not discriminate between the two species when they were switched, supporting a hypothesis of functional Müllerian mimicry in this group of similarly colored fishes. Ancestral state reconstructions and statistical comparisons of color pattern divergence in Tanganyikan Synodontis indicate that Müllerian mimicry in these catfishes has developed through diversification of an aposematic common ancestor with subsequent conservative mutualistic co-evolution among its daughter lineages, rather than advergent evolution of a mimic towards a non-related model, as assumed by widely accepted models of Müllerian mimicry evolution.
Link.
