These days,the sequencing of genomes and discovery of genomic regions associated with adaptive differences between populations and species are commonplace.What is less well understood is the role of gene expression in the ability of species to invade novel habitats and survive environmental challenges [1].Such an understanding is important,especially as numerous species are introduced to new regions of the globe through human intervention and spread as invasive species,often leaving ecological chaos in their wake.Additionally,we are only just beginning to understand the role of gene expression in acclimation of species to novel habitats [2,3].Both adaptation and acdimation are important in the ability of species to survive and invade new habitats [4,5].Measuring the relative contribution of these factors to invasive ability,and identifying signals of their genomic underpinnings,is a major task of evolutionary biology.