Primers, site data, and virus abundance in honey bees and Andrena spp.

Bees are focal pollinators, essential for maintaining biodiversity and crop production. Thus, reports of high annual honey bee colony losses and population declines among many wild bees in different parts of the world are of major concern. The spread of viruses is highlighted as a potential threat to bee communities. Viruses infect a wide range of bee species, and can be transmitted interspecifically through shared floral resources. Therefore, the role of flowers as hubs of bee virus transmission requires a community ecology perspective. Here, we investigate local and landscape-scale characteristics of floral communities potentially associated with the spread of viruses in the solitary Andrena spp. (mining bees). We surveyed 14 sites in a Mediterranean agroecosystem with varying local densities of honey bee (Apis mellifera) foragers and diversity of flowering species, and assessed the prevalence of four common Hymenoptera-associated viruses [deformed wing virus (DWV), black queen cell v..., We conducted a field survey during spring 2018, which included a total of fourteen sites. Each site comprised a 625 m2 plot located at the center of a larger wild bloom patch (mostly >3000m2). Field work was conducted in mid-March, corresponding to peak spring bloom, and lasted two weeks. Each site was sampled once between 8:00 and 16:00 when weather conditions were favorable for bee activity (temperature >17 °C, wind velocity <3 m/s, and clear or partially clear skies). Foraging bee sampling was carried out for a total of 40 person-minutes (excluding handling time of captured bees) and conducted by slowly walking throughout the plot and hand-netting any bee that was observed landing on a flower, while keeping records of the visited flower species. Each captured bee was identified in-situ to the lowest taxonomic level possible, immediately placed in a vial, and kept on dry ice. We collected additional foraging bees as needed to attain a sample of at least 11 Andrena and 11..., , # Primers, site data, and virus abundance in honey bees and Andrena spp.

[https://doi.org/10.5061/dryad.crjdfn3df](https://doi.org/10.5061/dryad.crjdfn3df)

## Description of the data and files structure

#### The dataset includes the following four tables:

**T1. Primers**

Lists the primers used in the qPCR assay for viral screening of the sampled bees. For each primer, the following attributes are specified: purpose, primer name, sequence (5’-3’), product size (bp), and reference.

**T2. Sites**

Contains detailed information on each surveyed site, including the following attributes: floral species richness (flowering plants visited by bees) as recorded during the survey, floral diversity (Shannon index), Floral Resource Availability (FRA) index computed based on land cover data, coordinates (UTM) of each site, forager density of *Apis mellifera* and *Andrena* (bees per 40 minutes), analysis sample size for each *Apis mellifera* and *Andrena* forager for each of the four viruses (BQ...,