Habitat preferences of nest-seeking bumble bees (Hymenoptera: Apidae) in an agricultural landscape

The aim of this study was to find out where bumble bee queens place their nests in the agricultural landscape. Nest-seeking behaviour was used to indicate nesting site preferences. Four types of agricultural landscape were investigated near Uppsala, Sweden: open, relatively open, relatively wooded and wooded. Twelve 500-metre-long transects, each including several intermingled habitats (e.g., field boundaries, pastures, clearings), were inspected repeatedly over a two-month period, from April to June 1991. In total, 147 observations of bumble bee queens (Bombus spp.) of eight species were recorded. Nest-seeking queens were observed most frequently along forest boundaries and field boundaries, in open uncultivated areas and in the relatively open landscape, whereas they were least frequent in forest and in clearings. Fields, pastures and road boundaries had intermediate frequencies. Differences among species were found in terms of both landscape type and habitat preferences: B. terrestris. B. lapidarius. B. sylvarum and B. subterranius preferred open terrain, whereas B. lucorum and B. pascuorum preferred forest boundaries. Withered grass and tussocks were the preferred nest-seeking patches among all species. (C) 2000 Published by Elsevier Science B.V. All rights reserved.