Individual study: Commercial nectar and pollen mixtures attract 30 species of flower-visiting insect at Rothamsted Research, Hertfordshire, England
Carreck N.L. & Williams I.H. (1997) Observations on two commercial flower mixtures as food sources for beneficial insects. Journal of Agricultural Science, Cambridge, 128, 397-403
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Plant dedicated floral resources on farmland
Carreck & Williams (1997) planted two or three plots of two commercial nectar and pollen mixtures Tubingen Mixture (40% phacelia) and Ascot Linde Mixture (25% phacelia) on farmland in Hertfordshire, England. Across two years, the plots attracted 14 species of bee, including all six common UK bumblebee species and three cuckoo bumblebee species Bombus [Psithyrus]. A small number of solitary bees of three species (no more than two individuals on any plot) were recorded. Phacelia attracted 87-99% of all bee visits over the two years of this study. Buckwheat, a nectar source that comprised 20% of both seed mixtures by weight, attracted 1% or less of all bee visits.
Plant nectar flower mixture/wildflower strips
A replicated study in 1994 and 1995 in Hertfordshire, UK (Carreck & Williams 1997) found that plots sown with two commercial nectar and pollen seed mixtures, Tübingen mixture (40% phacelia Phacelia tanacetifolia) and Ascot Linde mixture (25% phacelia) attracted 14 species of bees/wasp (Hymenoptera), including all six common UK bumblebee (Bombus spp.) species and three cuckoo bumblebee species Bombus [Psithyrus] spp. across two years. A small number of solitary bees (Andrenidae, Megachilidae) of three species (no more than two individuals on any plot) were recorded. The plots also attracted 14 hoverfly (Syrphidae) species and six butterfly (Lepidoptera) species. Phacelia attracted 87-99% of all bee visits and 31-98% of all hoverfly visits over the two years. Buckwheat Fagopyrum esculentum, a nectar source that comprised 20% of both seed mixtures by weight, attracted 1% or less of all bee visits, but up to 36% of hoverfly visits. Phacelia flowered for a long period on all plots. The main flowering period lasted four weeks, but some flowering continued for several months afterwards. The sown species successfully competed with previously existing weeds. In April 1994 Tübingen mixture was sown on a 25 x 25 m plot. In 1995 both mixtures were sown on 19 x 14 m plots; Tübingen mixture sown in April and May, Ascot Linde mixture sown in May and June. In each plot plants and flowers were counted in four 1 m2 quadrats. Insect density and diversity were recorded at least three times a week/plot.