S3-1.1 Wednesday, Jan. 4 Poecilogony, polymorphism or polyphenism: a window on larval evolutionary transitions in marine invertebrates KNOTT, K.E.*; MCHUGH, D.; University of Jyväskylä, Finland; Colgate University, USA email@example.com
Poecilogony, intraspecific variation in developmental mode, has been described in some marine invertebrates. Poecilogonous species produce different larval forms (e.g. free-swimming planktotrophic larvae as well as brooded lecithotrophic larvae). Poecilogony can be a controversial topic, since it is difficult to identify and characterize with certainty: does poecilogony represent polymorphisms with a genetic basis or is it a case of developmental polyphenism with phenotypes determined by plastic responses to environmental cues? Do common mechanisms underlie the developmental variation we observe in poecilogonous species? Is poecilogony maintained in different taxa via similar mechanisms or selective pressures? This symposium highlights recent research on poecilogonous species using a variety of approaches including comparative phylogenetic, developmental, ecological, genomic and transcriptomic, and population genetic studies. We hope to encourage further studies of poecilogony that integrate methods and perspectives from across sub-disciplines for understanding developmental mode transitions. Poecilogonous species provide a unique opportunity to elucidate the cellular, developmental and genetic mechanisms underlying evolutionary transitions in developmental mode, as well as help clarify the selective pressures and possible ecological circumstances that might be involved. Since such evolutionary transitions have occurred frequently in a wide range of invertebrate taxa, we expect the symposium to interest a wide audience. As an introduction, we describe an integrative approach to the study of poecilogony and its potential role in larval evolutionary transitions.