## 1 Introduction  
In urbanized environments, the expansion of urban areas has led to the creation of isolated green spaces such as gardens and parks [1]. These spatially constrained habitats are characterized by high biodiversity, hosting a variety of animals, among which are bees, birds, bats, and other mammals that traverse between urban and extra-urban spaces, including rural areas [2, 3, 4, 5, 6]. While urban gardens have been identified as places of refuge that provide resources for threatened species [7, 8, 9, 10], urban beekeeping has gained popularity, especially in metropolises and cities. New dimensions to the public debates on bees and beekeeping, the diversification of beekeeping opportunities, and novel motivations for beekeeping have clearly emerged based on social studies [11]. However, honeybees also contribute to a niche overlap [12] and increased opportunities for pathogen transmission [13]. Such dynamics underscore the importance of studying the presence and impact of pathogens in urban ecosystems, particularly in managed pollinators like _Apis mellifera_ [PERSON], 1758, and its wild counterparts. The extensive documentation of pathogens in honey bees, including over 70 different species of viruses [14], bacteria [15], and microsporidia [16], has revealed that many of these pathogens also infect other pollinator species [17; 18; 19; 20]. These data highlight that pathogens may significantly contribute to the observed decline in wild bee populations [21; 22]. However, for numerous wild bee species, particularly solitary ones, the role of these infectious agents in their survival remains poorly understood. For example, while it is known that wild bumblebees can be adversely affected by Deformed Wing Virus (DWV), Kashmir Bee Virus (KBV), and Israeli Acute Paralysis Virus (IAPV) [18; 23; 24], the impact of such viruses in solitary bees is largely unexplored [25; 26]. Similarly, _Nosema ceranae_ [PERSON] et al., 1996, initially associated with _Apis cerana_ [PERSON], 1793, and actually a global disease of _A. mellifera_[27], has also been documented to spill over into stingless bee species [28; 29], bumblebees [30; 31], and _Osmia biconnis_ ([PERSON], 1758) [32]. A recent review [33] updated the knowledge on the route of virus transmission in honeybees, with both horizontal and vertical transmission being considered. Most viruses first described in the _Apis_ spp. have also been detected in other bee species. Indeed, bee viruses can infect multiple hosts, and horizontal transmission seems to play a crucial role in the viral distribution patterns of bee species with different habits, with cleptoparasitic, communal, and ground-nesting species being more susceptible to infections [34]. Natural interspecies horizontal transmission can occur via several different routes, but oral-fecal transmission is most likely the main route. Several studies have pointed out the role of shared flowers in transmitting various bee pathogens (e.g., infected bees visiting flowers can contaminate the flower surface, nectar, and pollen with the virus particles they shed via their feces). Other less frequent interactions between bee species that could promote the transmission of viruses include robbing from other nests or colonies, brood parasitism, the reuse of nesting sites, and drifting. Finally, vector-mediated horizontal transmission could also be due to parasitoids, parasites, and commensals living in, on, or with the host bee or its nest structures [33]. Whatever the transmission route, the effectiveness of transmission is conditioned by the magnitude of the infectious load and the intrinsic resistance characteristics of the different viruses, which are differentiated and highly variable in relation to the environmental conditions [34]. The mite _Varroa destructor_ [PERSON] & [PERSON], 2000, is the primary driver of viral epidemics in honeybee populations for different viruses.