Plant-animal mutualistic networks are highly nested, meaning that more specialized species interact with subsets of species that more generalist species interact with. This pattern creates asymmetrical interactions and organizes the community around a central core of interactions. The study analyzed 52 mutualistic networks and found that nestedness increases with network complexity. Mutualistic networks are neither randomly assembled nor compartmentalized, but are highly nested. This nested structure has implications for the persistence and coevolution of biodiversity. The study also found that nestedness is more pronounced in networks with more interactions. The results suggest a non-random pattern of community organization that may be relevant for understanding the organization and persistence of biodiversity. The study used a nestedness calculator to measure nestedness and compared it with random models. The results showed that mutualistic networks are significantly more nested than other ecological networks. The study also found that nestedness is independent of network complexity. The results suggest that nestedness is a fundamental property of mutualistic networks and may have important implications for the coevolution of species-rich communities.Plant-animal mutualistic networks are highly nested, meaning that more specialized species interact with subsets of species that more generalist species interact with. This pattern creates asymmetrical interactions and organizes the community around a central core of interactions. The study analyzed 52 mutualistic networks and found that nestedness increases with network complexity. Mutualistic networks are neither randomly assembled nor compartmentalized, but are highly nested. This nested structure has implications for the persistence and coevolution of biodiversity. The study also found that nestedness is more pronounced in networks with more interactions. The results suggest a non-random pattern of community organization that may be relevant for understanding the organization and persistence of biodiversity. The study used a nestedness calculator to measure nestedness and compared it with random models. The results showed that mutualistic networks are significantly more nested than other ecological networks. The study also found that nestedness is independent of network complexity. The results suggest that nestedness is a fundamental property of mutualistic networks and may have important implications for the coevolution of species-rich communities.