In natural communities, the organization of interactions between species often presents non-random patterns at the origin of complex network structures. There is growing evidence that these particular structures can affect long-term species coexistence and stability. Several studies have highlighted structural differences between networks depending on the type of ecological interaction involved, i.e. mutualistic or antagonistic. Theoretical studies also revealed that the links between network structure and stability strongly differed between mutualistic and antagonistic webs. However, studying networks based on a single kind of interaction (e.g. food web, pollination web, etc.) is a simplification because species are often involved in different interaction networks either simultaneously or at different life stages.
Following recent calls for the consideration of diverse types of interactions in ecological networks, we investigate the links between structure and stability in networks with both mutualistic and antagonistic interactions. More specifically, we ask the following questions: 1) To what extent do structural characteristics known to promote stability in networks made of a single interaction type still matter for the stability of networks with interaction type diversity? 2) What is the structure of networks made of different types of interactions and what are their consequences for stability?
We investigate these two questions by using both theoretical approaches with dynamical models of interaction networks, and analyses of an empirical dataset describing the network of interactions between plants, herbivores and pollinators.