Fig. 4: Visited plants and their flower traits.

a, Plant species that received the most visits by honeybees in May/June and July (mean values ± s.e.m., n = 123 observations from 12 landscapes). The insert is displaying the types of flowers most frequently visited by honeybees. b, The six species with the highest mean number of visits were Helianthus annuus, Phaseolus vulgaris, Origanum vulgare, Centaurea jacea, Trifolium repens and Knautia arvensis and their flower type is indicated. Additionally, examples for the flower types ‘tube’, ‘brush’, ‘bell-trumpet’ and ‘stalk-disk’ are given with images of Symphytum officinale, Phyteuma spicatum, Campanula spp. and Pulmonaria spp. as example taxa are shown. c,d, NMDS visualizing Bray–Curtis dissimilarity distances among the 20 pollinator species screened for viruses preferring plant species with different flower traits. The pollinator species are grouped by load (mean number of genome copies per microgram RNA) of BQCV (c) and DWV-B (d). Numbers in c and d indicate specific pollinator species: HB, honeybees; 1, Andrena humilis; 2, Bombus hortorum; 3, B. humilis; 4, B. hypnorum; 5, B. lapidarius; 6, B. lucorum; 7, B. pascuorum; 8, B. ruderatus; 9, B. subterraneus; 10, B. sylvarum; 11, B. terrestris; 12, Halictus scabiosae; 13, Lasioglossum glabriusculum; 14, L. malachurum; 15, L. morio; 16, L. pauxillum; 17, Melanostoma mellinum; 18, Sphaerophoria philanthus; 19, Syrphus vitripennis. Credit: Phaseolus vulgaris photo © Thomas Bresson, https://www.flickr.com/photos/computerhotline/, under a Creative Commons licence CC BY 2.0.