How wild bees find a way in European cities: Pollen metabarcoding unravels multiple feeding strategies and their effects on distribution patterns in four wild bee species

Urban ecosystems can sustain populations of wild bees, partly because their rich native and exotic floral resources. A better understanding the urban bee diet, particularly at larval stage, is necessary to understand biotic interactions feeding behaviour in ecosystems, promote bees by improving management We investigated diet distribution patterns four solitary species with different specialization (i.e. Chelostoma florisomne, Osmia bicornis, cornuta Hylaeus communis) along intensity gradients five European cities (Antwerp, Paris, Poznan, Tartu Zurich) using two complementary analyses. Specifically, trap-nests pollen metabarcoding techniques, we characterized species' assessed consistency across modelled models (SDMs). Our results demonstrate that display successful strategies exploit existing resources: not only broad generalism H. but also intermediate generalism, some degree conservatism plant family or genus level O. bicornis), even strict on widely available hosts C. florisomne). Furthermore, detected important variation communis, a switch from an herbaceous tree increasing intensity. Species modelling indicated ranges inside ultimately depend specialization, broader diets result less sensitivity Policy implications. Satisfying dietary requirements critical preserving enhancing distributions within gradients. For high levels found considerable preferred families genera studied cities, which could be generalized other where these occur. Identifying preferences (e.g. metabarcoding) helpful for identifying key taxa traits survival develop bee-friendly cities.