Fishing for a thesis in a sea of cryptic signals: plasticity & adaptive differentiation in sticklebacks of the St. Lawrence River estuary
Friday seminar by R. J. Scott McCairns
Disentangling the relative contributions of selective and neutral processes underlying phenotypic and genetic variation under natural, environmental conditions remains a central challenge in evolutionary ecology. One area of continued interest in this research programme is the role of phenotypic plasticity: does plasticity define a 'neutral' alternative to local adaptation, or is the process of adaptive evolution a continuum enabled and/or inhibited to varying degrees by plasticity? During the course of my doctoral research I attempted to address these themes through a study of parapatric threespine stickleback demes. The threespine stickleback (Gasterosteus aculeatus) has emerged as an important model organism in evolutionary ecology, largely due to the repeated, parallel evolution of divergent morphotypes following colonization of freshwater habitats. However, adaptive divergence is not a universal phenomenon, and the potential for phenotypic plasticity in this model has been of little interest in recent years. The St. Lawrence River estuary presented an in interesting system in which to explore evolutionary dynamics on an ecological timescale given the ecosystem's relatively recent geologic origins, and both the discrete and clinal variation defining its contemporary ecology. I used a combination of observational and experimental approaches to describe variation in behavioural, physiological and morphological traits, and attempted to infer putative underlying processes that explained these data. In this seminar, I will provide a summary of the more salient findings from this research with the aim of highlighting the potential utility of studying inherently plastic traits from an evolutionary perspective.
R. J. Scott McCairns
Ecological Genetics Research Unit (EGRU)
Department of Biosciences, University of Helsinki