Abstract
Dispersal distributions of solitary bees and bumblebees were studied in a winter oilseed rape field. Window-traps were placed in the rape field along a line transect perpendicular to the field edge. 19 species of solitary bees were recorded and all but four species are polylectic, including Brassicaceae as host-plant family. Through non-linear regression, the decline in solitary bee individuals versus distance from field edge significantly fitted a steep two-parameter exponential decay function. Activity of solitary bees was clearly highest within 30 metres from the field edge. Apparently, solitary bees do not play any noteworthy role in the pollination of winter oilseed rape in Denmark. The traps yielded ten species of bumblebees, and a significant linear correlation was found between numbers of individuals and distance from the field edge. This result is attributed to bumblebee foraging behaviour. Bumblebees were abundant and presumably are important background pollinators of oilseed rape. Honeybees are managed pollinators of oilseed rape, and were abundant in a preceding study of the area. For unknown reasons, honeybees were caught in extremely low numbers in this study, and the most likely explanation is a decline in honeybee populations
| Originalsprog | Engelsk |
|---|---|
| Udgivelsessted | Department of Population Ecology, University of Copenhagen |
| Sider | 61-71 |
| Antal sider | 11 |
| Status | Udgivet - 2000 |