Decoupled evolution of foral traits and their phenotypic covariances in Salvia

DOMINGUEZ C. A.; BENITEZ-VIEYRA, S; FORNONI, J; SAZATORNIL, F; IZQUIERDO, J

Montpellier

Congreso; Second Joint Congress on Evolutionary Biology; 2018

European Society for Evolutionary Biology (ESEB), American Society of Naturalists (ASN), Society for the Study of Evolution (SSE), Society of Systematic Biologists (SSB)

Morphospaces, or phenotypic spaces in general, are representations of the multidimensional nature of organisms. The clumped distribution of species inside morphospace imposes an outstanding question: Does it mirror the narrow set of solutions to functional problems or is it the product of constrictions and channelling in genetic and developmental systems? Here we extend the scope of morphospaces and built the space of variance-covariance phenotypic matrices, which allows to explore the evolutionary causes and consequences of trait covariances. As they result from the underlying genetic and developmental architecture, it also lets to analyse how constraints evolve.We built the morphospace and the phenotypic covariance space of six floral traits from eighteen Neotropical Salvia species, a clade that has experienced a recent adaptive radiation, being pollinated either by hummingbirds or bees. As these pollinator guilds strongly differ in their cognitive abilities and how they manipulate flowers, we expected that pollinator-mediated selection resulted not only in divergence in flower morphology but also in divergence in phenotypic covariance structure. These expectations were also tested at microevolutionary level in five species, using selection studies in the field. Short term changes in phenotypic means, variances and covariances due to selection were visualized inside phenotypic spaces, along with the expected changes due to random drift. The morphospace and the phenotypic covariance space differed in how close were the clusters of hummingbird and bee-pollinated Salvia species, being clearly separated only inside the morphospace. Short term changes due to selection could be reshaping phenotypic covariances in one species.