Structural differences in individual pollinator networks across bee species reveal the importance of population‐level processes in the assembly of species interactions

Patterns of community‐wide interactions have been typically evaluated at the species level while overlooking how differences in individual behaviour within a species may influence the structure of species interactions. Characterising and comparing individual‐level interaction network structure across multiple species could help reveal the role that population‐level processes (e.g. intraspecific competition and individual niche redundancy) play in structuring species‐wide interactions. We characterised individual‐ and species‐level plant–pollinator networks using pollen loads of over 500 insects that foraged on ~40 plant species. We further compared individual‐level network properties among three well‐sampled pollinator species to uncover signals of population‐level processes structuring species interactions. We also evaluated the role of two potential drivers (body size and sex differences) mediating differences in pollinator foraging niche breadth and individual network structure. Individual pollinators were more specialised compared with ‘random samplers’ of their overall species' diet (based on null model expectations), suggesting high individual niche partitioning. We also observed differences in patterns of individual‐level network structure and degree of individual specialisation among pollinator species. These differences suggest that both niche differentiation and redundancy at the population level may contribute to the structure of species‐wide interactions, with unknown consequences for pollination success. Intraspecific variation in body size did not affect pollinator niche at the species level. However, female bees were more specialised than males, suggesting sex‐based differences contribute to variation in individual specialisation. Synthesis. By using individual‐level networks within a comparative framework, this study advances our understanding of how individual foraging patterns may scale up to structure species‐level plant–pollinator networks. In doing so, this study further aids in helping resolve perceived conflicts between specialisation and generalisation in plant–pollinator communities.