Accurately describing the network structure of ecological communities is key to understanding their stability and disturbance responses. Herbivory and pollination networks between plants and insects generally exhibit high modularity and nestedness, respectively, with theoretical support that such structures enhance stability. Notably, most pollinating insects undergo metamorphosis, acting as herbivores during their larval stage without contributing to pollination. However, the role of their ontogenetic niche shifts in maintaining the stability of coupled herbivory-pollination networks (i.e. hybrid communities) remains unclear. Here, we ask whether larval herbivory or adult pollination networks are more crucial for the stability of stage-structured hybrid communities. We constructed bipartite random network topologies for both stages, varying stage-specific network connectance. Comparing ontogenetic niche shift patterns with field data revealed that herbivory network modularity closely matched model predictions, while pollination network nestedness deviated positively. Additionally, adult niche expansion aligned with predictions based on connectance, but not with those based on modularity and nestedness. Therefore, while pollinating adults may face certain constraints in expanding host plant niches, they likely select host plants non-randomly, thereby increasing pollination network nestedness. We suggest that adult pollination networks would be more crucial for the stability of stage-structured hybrid communities.