## 2 Materials and Methods
### Statistical Analyses  
Statistical analyses were performed using Rstudio v. 4.4.0 [67]. Plant-pollinator networks were obtained using the R bipartite package [68]. Networks were built with the total number of specimens per pollinator taxa per area for the whole monitoring period and the plant species to which they were associated. In this analysis, plants were considered as the lower level and pollinators as the higher level. For each network, the following metrics at the network level were calculated: the number of taxa at both levels, links per taxa, the mean number of shared partners, the niche overlap as the mean similarity in interaction between taxa of each level, the partner diversity as the mean Shannon diversity index for the number of interactions, and the Shannon diversity index of interactions [68], and the modularity. Modularity is a measure of how well links and interactions can be separated into different groups or modules of plant and pollinator species that interact more within their module than between modules. It ranges from 0 to 1, and it is higher when each module appears isolated from the rest of the network [69; 70; 71]. To better understand the variations in each network metric with urban greenery, ANOVA, Welch's ANOVA, and the Kruskal-Wallis test were performed based on the satisfaction of the normality and homoscedasticity assumptions. To study the differences in each network metric over the two sampling years, the \(t\)-test and Wilcoxon-Mann-Whitney test were performed based on the satisfaction of the normality and homoscedasticity assumptions. Pairwise comparisons were then performed. To further elucidate the competitive dynamics among pollinator taxa, defined as the utilization of shared plant resources by different pollinators within a network, [PERSON]'s index was calculated through the Potential for Apparent Competition (PAC), as outlined by [68; 72] within the bipartite package. This index was calculated as the potential influence of an acting bee (here _A. mellifera_) on a target bee via shared plant species [73]. [PERSON]'s index ranges from zero, indicating no plant sharing and thus no competition between pollinators, to one, denoting high plant sharing and high competition between the acting and target bees [73; 74]. [PERSON]'s index was calculated for all the taxa in the six areas for each year. _Apis mellifera_ was the acting bee, and the target bees selected were the ones that, in 2019, resulted as dominant and the ones that were also selected for pathogen spillover. The target bees were _Anthidium_ spp., _An. forentinum_, _B. terrestris_, _B. psucorum_, _M. sculpturalis_, and _O. cornuta_. For the year 2020, the index was not calculated for _An. forentinum_ as the identification at the species level for this genus was not available. The variations in [PERSON]'s index between the selected bees and the different urban greenery were analyzed with the Kruskal-Wallis test. To understand whether the apparent competition changed over the years, we used the Wilcoxon-Mann-Whitney test.  
Finally, linear discriminant analysis was used to group the green areas according to virus presence and load and the biodiversity.