A novel farmland wildflower seed mix attracts a greater abundance and richness of pollinating insects than standard mixes

Wildflower strips are a popular agri-environment scheme (AES) implemented on farmland to provide forage for insect pollinators. The standard seed mixtures were often formulated without a clear evidence base, and subsequent field trials to assess their attractiveness to insects are commonly carried out at low taxonomic resolution (e.g., pooling all ‘solitary’ bees). We created two novel wildflower mixes: a wild bee mix based on primary research (WB) and one on literature-based evidence (LT). We trialled our novel mixes against two standard AES wildflower mixes: a Fabaceae-heavy mix (FAB); a diverse wildflower mix (WF); plus a fallow plot (control). Our aim was to determine which mix attracted the highest overall insect pollinator abundance and highest species richness for wild bees. Our WB mix attracted both the highest number of total insect visitors, and the highest wild bee abundance and richness. WB attracted significantly more bumblebees (abundance and richness) than the typical low diversity, Fabaceae-heavy mix (FAB); and significantly greater solitary bee abundance, than all other treatments. Only 11 ‘key’ wildflower species were required to cater to all wild bee species recorded during the study, eight of which were sown species. Taraxacum officinale agg., Cirsium vulgare, Daucus carota and Geranium pyrenaicum received the highest numbers of wild bee species visits. In conclusion, we suggest a novel wildflower seed mix based on primary research has the potential to provide more attractive forage for both wild bees and other insect pollinators compared to current AES mixes.