Data from: Drivers and cascading ecological consequences of Gambusia affinis trait variation

Phenotypic trait differences among populations can shape ecological
outcomes for communities and ecosystems. However, few studies have
mechanistically linked heritable and plastic components of trait variation
to generalizable processes of ecology, such as trophic cascades. Here we
assess morphological and behavioral trait variation in nine populations of
common-garden reared western mosquitofish (Gambusia affinis) from three
distinct ancestral predator environments (three populations per
environment), each reared in the presence and absence of predator cues. We
then use a pond mesocosm experiment to examine the ecological consequences
of trait variation and density variation. Our results show significant
among-population trait variation, but this variation was generally
unrelated to ancestral predator environment. When traits did vary
congruently with respect to ancestral predator environment, this trait
variation was driven by gene-by-environment interactions. Variation in
several mosquitofish traits altered the cascading effects of mosquitofish
on zooplankton and primary producers, but the effect of any given trait
was typically weaker than that of density. We note that the relatively
stronger ecological effects of density may mask the effects of traits in
some systems. Our example here shows that trait variation can be highly
noncongruent with respect to a perceived selective agent, phenotypic
change is a product of complex interactions between genes and the
environment, and numerous interacting phenotypes generate significant but
potentially cryptic cascading ecological change.