Evolutionary history and ecological traits shape a mutualistic plant-hawkmoth interaction network

Multiple non-exclusive processes influence species interactions and shape ecological networks. Although evolutionary history may influence interactions via shared inherited traits, its relative importance in comparison neutral and niche-based processes remain poorly understood. Here we investigate the effects of evolutionary history on interaction frequencies and the emergence of modularity in interaction networks compared to ecological and neutral processes through a study case of a plant-hawkmoth network on Pampa grasslands. Using morphological, phenological, abundance and phylogenetic data for every species in community, we found that interaction frequencies increase as morphological matching and phenological overlap increase, and evolutionarily isolated hawkmoth species tend to interact with plants more frequently. Further, by evaluating whether hawkmoth composition differs among interaction modules, we found that modules encompass phylogenetically distant and functionally distinct hawkmoth species. These results along with the phylogenetic signal detected for morphological traits suggest that competition among pollinators shape interaction patterns. Nevertheless, modules composition may indicate that despite evolutionary history and ecological traits influence interactions frequencies, modules emergence is not only directly influenced by these processes, but potentially also by a strong environmental filtering or stochastic factors.