FORAGE FOR BUMBLE BEES AND HONEY-BEES IN FARMLAND - A CASE-STUDY

Bee visits and the abundance of flowers of different plant species were recorded on a standard walk through UK farmland on 30 occasions in 1989 (the seasonal survey), and in dawn-to-dusk studies. Most of the species visited by bees were perennials. In the seasonal survey (a total of 1 221 bee visits), most visits were made by the long-tongued bumble bee, Bombus pascuorum (447) and by honey bees, Apis mellifera (321). Another long-tongued bumble bee, B. hortorum, was also abundant. The main forage plants important for both long-tongued bumble bee species comprised a seasonal succession of labiates: Lamium album, Stachys sylvatica and Ballota nigra. Plants visited by shorter-tongued bumble bees (B. terrestris/B. lucorum, B. pratorum and B. lapidarius), and honey bees, included Rubus fruticosus agg., Cirsium vulgare, Epilobium hirsutum, Heracleum sphondylium and Brassica napus, and probably other plants outside the survey area. Dawn-to-dusk studies showed that long-tongued bumble bee species were largely responsible for pollinating visits to field bean, Vicia faba, and that B. pascuorum began foraging earlier and finished later in the day than A. mellifera. Bee visits were unevenly distributed among the 18 sections of the farm walk in the seasonal survey. The sections that received most bumble bee (and honey bee) visits supported a seasonal succession of forage plants with abundant Ballota nigra and R. fruticosus agg., E. hirsutum and Brassica napus, and L. album, which was important in early summer. Sections on gravel rather than clay soils and with a hedge and ditch received numerous bumble bee visits. The best sections were areas undisturbed by cultivation or grazing, in which perennials other than Urtica dioica could establish. Bumble bee forage could be improved by managing and extending field margins and other uncultivated areas on the farm.