Multilayer Network Structure of Diptera–Hymenoptera Parasitoid Associations Across Organic Resources in Brazil

Diptera developing in decomposing organic resources interact with diverse hymenopteran parasitoids, but conventional aggregate analyses can obscure the resource context in which individual trophic links occur. This study reconstructed an audited multilayer network from experimental records obtained in Brazil, treating organic resource, dipteran host, and parasitoid as an explicit three-component ecological record. The primary dataset comprised 29 dipteran host taxa, 27 hymenopteran parasitoid taxa, 12 resource layers, 171 unique Resource × Host × Parasitoid triplets, and 125 unique Host × Parasitoid edges. Aggregate connectance was 0.160 and all retained taxa belonged to a single connected component. Parasitoids occupied more resource layers on average than hosts, while pairwise comparisons showed that parasitoid identity was shared among resources more frequently than identical Host × Parasitoid interactions. The aggregate network was significantly modular (Qb = 0.413; null mean = 0.358 ± 0.010; z = 5.59; p = 0.001), whereas nestedness was not greater than null expectation (NODF = 32.689; z = −1.93; p = 0.962). Connector analysis showed that cross-resource and inter-module connectivity was distributed among several taxa rather than concentrated in a single hub. The results demonstrate that resource identity retains biologically meaningful information that is lost when host-parasitoid records are collapsed into a single matrix and support a multilayer interpretation of parasitoid assemblages in dung, animal tissues, carrion, fish, fruit, and food residues.