Monday, December 10, 2007 - 8:05 AM

Systematics and color mimicry evolution of the cyanide-producing millipedes of Appalachia

Paul Marek, and Jason Bond, East Carolina University, Biology Department, Howell Science Complex/N211, Greenville, NC

Individuals in the millipede genus Brachoria display extremely variable color patterns serving to warn predators of cyanide. Across its range members are often visually identical to other apheloriine species with sometimes five similarly patterned species at a locality, hypothetically representing MŁllerian mimicry. Theoretical predictions suggest: (1) mimic species emulate the most abundant and/or most defended model; (2) overlap in the aposematic signal of the model and mimic is not attributable to relatedness; and (3) signal divergence across the mimicís distribution is predicted by the modelís. To test hypothesis 2, we reconstructed apheloriine evolutionary history to determine the phylogenetic distance between co-mimics. Phylogenies recover deep divergence between co-mimics suggesting overlap is not a result of close ancestry, but of unique selection toward signal convergence at a locality. In addition to providing a framework to address taxonomy, the phylogeny provides a context for a phylogeographic study testing predictions 1, 3, and co-mimic abundances formulated by original theoretical models of mimicry.

Species 1: Polydesmida Xystodesmidae (millipedes)