Field experiment set-up
To assess the individual and interactive effects of the two stressors
herbivory and lack of pollination on faba bean, we conducted a cage
experiment in 2020 in a faba bean field in Uppsala, Sweden
(59°50’29.12”N; 17°42’02.44”E). We conducted a fully-crossed
two-factor field experiment, with presence and absence of herbivores
(H+/H-) and pollinators (P+/P-), where H+ and P- were the stressed level
of each factor. Each H and P treatment combination had seven replicates
(N=28 in total), arranged in seven blocks, with one treatment
combination per block (Fig. S2). We used 2x2x2 m cages covered with a
nylon net (mesh size: 0.6x0.6 mm) to control the access of the
herbivores and pollinators to the crop. Faba beans seeds (cultivar:
Tiffany, Scandinavian Seed) were planted in the field on the
24th of April (plant density per m2:
mean±sd = 58.4±8.5), and plants were treated with the fungicide Signum
(0.5 kg.ha-1, BASF; 267 g.kg-1boscalid + 67 g.kg-1 pyraclostrobin) on the
15th of June, before flowering (BBCH-51) and prior to
bumblebee hive inclusion, to avoid negative impacts on pollinators
(Fisher et al., 2021).