How effective are artificial nests in attracting bees? A review

Abstract

Abstract Background Recent declines in bee populations, along with increasing demand for pollination services in urban, agricultural, and natural environments, have led to strategies to attract wild bees to these areas. One of these strategies is installing artificial nests adjacent to urban gardens and agricultural farms. Bee hotels and nest boxes are among the artificial nests used by gardeners and farmers to attract pollinators. In this paper, we reviewed 50 studies that reported the efficiency of nest boxes and bee hotels in attracting bees. We considered the maximum occupation rate (percentage) as the main index to evaluate the efficiency of artificial nests. Results The maximum occupation rate of bee hotels was higher in farms (averaged 44.1%) than in forests (averaged 30.3%) and urban (averaged 38.3%) environments. In the case of nest boxes, most studies reported efficiencies of less than 20%, with an occupation rate of 16% and 5.5% on average in forest and urban environments respectively. However, our meta-analysis results showed that there was no significant relationship between the occupation rate of the nests and their installation place. Regression analysis also showed that the structural features of bee hotels (length and diameter) and nest boxes (volume and entrance size) did not affect their efficiency in attracting bees. Conclusion Our data showed that the strategy of installing artificial nests to attract pollinators is successful only concerning bee hotels, and the use of nest boxes has not been very successful.