Agriculture, Ecosystems and Environment 77 2000 247–255
Habitat preferences of nest-seeking bumble bees Hymenoptera: Apidae in an agricultural landscape
Birgitta Svensson
a,∗
, Jan Lagerlöf
a
, Bo G. Svensson
b
a
Department of Ecology and Crop Production Science, SLU, P.O. Box 7043, S-750 07 Uppsala, Sweden
b
Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18 D, S-752 36 Uppsala, Sweden Received 14 December 1998; received in revised form 27 May 1999; accepted 23 July 1999
Abstract
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. ©2000
Published by Elsevier Science B.V. All rights reserved.
Keywords: Bumble bees; Bombus; Nest-seeking; Agricultural landscape; Habitat selection; Sweden
1. Introduction
With the modernisation of agriculture, the habitats that many animals and plants rely on for their survival
have deteriorated. Meadows and pastures have disap- peared to a great extent, and covered drains have re-
placed ditches. In the intensively utilised agricultural landscapes of today, field boundaries and roadsides
have come to serve as major refuges for many species
∗
Corresponding author. Tel.: +46-18-672526; fax: +46-18- 673430.
E-mail address: birgitta.svenssoneom.slu.se B. Svensson.
because they are the only non-cultivated habitats left see, e.g., Lagerlöf and Wallin, 1993, for review.
Bumble bees are vital from the standpoint of agri- culture and conservation because they pollinate crops,
fruit trees and wildflowers. However, for bumble bees to be effective, they must have local access to suitable
nesting and hibernation sites, as well as to alternative food sources i.e., wildflowers during periods when
crop plants are not flowering Fridén, 1967; Fussell and Corbet, 1992a. A Norwegian study found the
home range size of bumble bees to be only 250–350 m from the nest Dramstad, 1996.
For recording the occurrence and activities of bumble bees, one has to distinguish between castes
0167-880900 – see front matter ©2000 Published by Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 - 8 8 0 9 9 9 0 0 1 0 6 - 1
248 B. Svensson et al. Agriculture, Ecosystems and Environment 77 2000 247–255
queens, workers and males in order to gain a proper understanding of their use of resources over time and
space Svensson and Lundberg, 1977. Only a few studies have been made on bumble bee nesting-site
preferences and characteristics of the nesting sites Skovgaard, 1936; Svensson and Lundberg, 1977;
Richards, 1978; Fussell and Corbet, 1992b.
Nest-site preferences of bumble bees have been in- vestigated by setting out artificial nests in the field.
However, only a very small percentage of such nests are ever used Richards, 1978; Fussell and Corbet,
1992b. It can, therefore, be advantageous to observe nest-seeking queens in spring, because a larger amount
of data can be gathered in this way. This method was mentioned by Skovgaard 1936, and used by Richards
1973 and Svensson and Lundberg 1977.
The present investigation aimed at estimating the abundance of nest-seeking bumble bee queens in dif-
ferent types of agricultural landscapes and habitats, with special emphasis on uncultivated areas.
2. Material and methods
