Meeting Abstract

S2-2.3  Wednesday, Jan. 4  Plasticity, integration, and selection: prospects for exploring the evolution of complex phenotypes in a powerful fish model EARLEY, Ryan L.*; HANNINEN, Amanda F; FULLER, Adam; GARCIA, Mark J; STANLEY, Shane; LEE, Elizabeth A; TAYLOR, D. Scott; University of Alabama; Brevard County Environmentally Endangered Lands Program rlearley@bama.ua.edu

Identifying where individuals ‘precipitate out’ in phenotypic space requires knowledge of how selection, constraint, and plasticity interact to shape behavioral, morphological, and life history traits. In any organism, this is a Herculean effort but sometimes we stumble upon species with novel characteristics uniquely suited to fill empirical niches within the biological sciences. The mangrove rivulus (Kryptolebias marmoratus) is the only known self-fertilizing, hermaphroditic vertebrate. Its unique style of sexual reproduction results in extensive inbreeding, and the natural generation of isogenic lineages whereby a homozygous parent produces offspring genetically identical to itself and all sibs. Males exist at low frequencies in a population, providing opportunities for outcrossing and the maintenance of high genetic diversity within and among populations. This species thus provides unprecedented opportunities to generate reaction norms for an arsenal of phenotypic traits with replication at the genotypic level; explore local adaptation and the genotypic/genomic basis for phenotypic diversity; and identify patterns of trait covariance driven by pleiotropic effects of genes or hormones that might constrain or liberate phenotypic evolution. We have collected over 200 genetically distinct lineages from 30 populations throughout the mangrove rivulus’ range, extending from Central America to the Caribbean and coastal regions of central Florida. We reveal significant behavioral, morphological, and life history diversity among genotypes; a high degree of plasticity in response to the social and physical environments both during ontogeny and adulthood; and a potentially potent role for steroid hormones as integrators of suites of phenotypic traits.