Evolution of butterfly-plant networks over time, as revealed by Bayesian inference of host repertoire

The study of herbivorous insects underpins much of the theory that concerns the evolution of species interactions. In particular, Pieridae butterflies and their host plants have served as a model system for studying evolutionary arms-races. To learn more about how the two lineages co-evolved over time, we reconstructed ecological networks and network properties using a phylogenetic model of host-repertoire evolution. In tempo and mode, host-repertoire evolution in Pieridae is slower and more conservative when compared to similar model-based estimates previously obtained for another butterfly clade, Nymphalini. Our study provides detailed insights into how host shifts, host range expansions, and recolonizations of ancestral hosts have shaped the Pieridae-angiosperm network through a phase transition from a disconnected to a connected network. Our results demonstrate the power of combining network analysis with Bayesian inference of host repertoire evolution in understanding how complex species interactions change over time.