Biological factors contributing to bark and ambrosia beetle species diversification

The study of species diversification can identify the processes that shape patterns of species richness across the tree of life. Here we perform comparative analyses of species diversification using a large dataset of bark beetles. Three examined covariates – permanent inbreeding (sibling mating), fungus farming, and major host type – represent a range of factors that may be important for speciation. We studied the association of these covariates with species diversification while controlling for evolutionary lag on adaptation. All three covariates were significantly associated with diversification, but fungus farming showed conflicting patterns between different analyses. Genera that exhibited interspecific variation in host type had higher rates of species diversification, which may suggest that host switching is a driver of species diversification or that certain host types or forest compositions facilitate colonization and thus allopatric speciation. Because permanent inbreeding is ...