Stable resource polymorphism along the benthic littoral-pelagic axis in an invasive crayfish

Although intraspecific variability is now widely recognized as affecting evolutionary and ecological processes, our knowledge on the importance of intraspecific variability within invasive species is still limited. This is despite the fact that quantifying the extent of within-population morphological divergences associated with the use of different trophic or spatial resources (i.e. resource polymorphism) can help to better predict their ecological impacts on recipient ecosystems. Here, we quantified the extent of resource polymorphism within populations of a highly invasive species, Procambarus clarkii, in 16 lake populations by comparing their trophic (estimated using stable isotope analyses) and morphological characteristics between individuals from the littoral and pelagic habitats. Our results first demonstrated that crayfish occur in both littoral and pelagic habitats of 7 lakes and that the use of pelagic habitat was associated with increased abundance of crayfish in the littora...