Assessing the efficacy of artificial domiciles for bumblebees

Bumblebees have suffered declines as a result of reduction in habitat availability associated with agricultural intensification. Although several conservation strategies for bumblebees address forage availability, other aspects of bumblebee ecology are often ignored. Availability of sufficient nest sites is a key requirement of bumblebee populations and since nesting habitat is likely to have become reduced on intensively farmed land, lower nest site availability may contribute to bumblebee declines. The use of artificial domiciles for bumblebees has been proposed as a potentially useful tool for conservation and for improving pollination services for crops, providing a method of boosting nest site availability where it is otherwise limiting. Here, six different artificial domiciles for bumblebees are trialled in different habitats in southern England and central Scotland. Of these, only one domicile design at one particular site achieved reasonable uptake rates, whilst all other combinations of domicile and site achieved low success. Overall, only 23 of 736 domiciles deployed were occupied by bumblebees (3.1%). Based on current knowledge, attempts to use domiciles for conservation or research in the UK are likely to be ineffective. Commercially available domiciles for bumblebees performed poorly in these trials and the implications of these findings for manufacturers are discussed.