Flower visitor observations
Observations were carried out between July
2nd-10th at appropriate weather
conditions (warm, sunny, dry). One m² of each plot was observed for 15
min. Due to time limitations and withering of linseed, only one
replicate out of four could be observed twice. We assessed numbers of
flower visits and flower visitor species (if possible, orders
otherwise), on monocultures of wheat, faba bean and linseed, their two-
and three-species mixtures and control plots where no crop was sown, but
where weeds established (Table S9). We recorded which plant species was
visited for both crops and weeds for each plot and counted every contact
with floral organs as one visit. When the ears of wheat plants were
visited, this was also counted as a flower visit, as it has been shown
that hoverflies and bees also visit wind-pollinated plants (Saunders
2018). For data analyses, we summed all observations per crop diversity
(four levels, see Staab et al., 2015) and per crop mixture (eight
levels).