Giulio Dalla Riva School of Mathematics & Statistics, University of Canterbury Title: To Build a Web You Need a Tree, and Vice Versa Abstract: A food web is a (weighted) directed graph describing the observed energy fluxes within a community of species, that is, the who-eats-who network. A phylogeny is a ((ultra)metric) labelled rooted tree describing the evolutionary history of a community of species. From the ecological literature we know that food webs are stochastic processes shaped (also) by the species' evolutionary history. Hence, on one hand, we should be able to see a phylogenetic signal in the food web topologies. As an example, closely related species have similar motifs distributions. On the other hand, predation relationships are drivers of species evolution. Hence, food webs dynamics concur to shape phylogenetic trees. We will see how, adopting a Random Dot Product Graphs representation, we can give reason of food web inherent stochastic nature. Moreover, the RDPG representation allows us to describe each species in terms of functional traits. We will see, indeed, that RDPG-functional traits do show a phylogenetic signal. However, can we take explicitly into account ecological relationships?