Prey and prejudice: predation by the European bee‐eater <i>Merops apiaster</i> has species‐specific effects on the ecology and genetics of bumblebees

Predation is a major ecological force, but its effect on bees has rarely been studied. Here, we investigated whether the presence of the European bee‐eater Merops apiaster , a migratory bird species and major bee predator, decreases the abundance and body size of three common bumblebee species ( Bombus lapidarius , B. terrestris and B. pascuorum ) in Germany compared to nearby sites without the predator. Overall, our results provide strong evidence that bee‐eater sites harbour fewer and smaller bumblebees compared to sites without the bird, although the effects were species‐specific. Furthermore, we analysed if the reduced abundance of B. lapidarius and B. pascuorum at bee‐eater sites translates into a lower effective population size ( N e ) and genetic diversity using genome‐wide SNP markers, which did not seem to be the case for neither of the two species. Overall, bee‐eaters seem to negatively influence the abundance and body size of bumblebees but not (yet) their population genetics. Counteracting the negative effects of predation on bees by appropriate habitat management will be especially relevant in the future, as bee‐eaters are winners of global warming.