Current evidence demonstrates that a sixth major extinction of biological diversity event is underway.1. The Earth is losing between one and ten percent of biodiversity per decade2, mostly due to habitat loss, pest invasion, pollution, over-harvesting and disease3. Certain natural ecosystem services are vital for human societies. Many fruit, nut, vegetable, legume, and seed crops depend on pollination. Pollination services are provided both by wild, free-living organisms (mainly bees, but also to name a few many butterflies, moths and flies), and by commercially managed bee species. Bees are the predominant and most economically important group of pollinators in most geographical regions. The Food and Agriculture Organisation of the United Nations (FAO)4 estimates that out of some 100 crop species which provide 90% of food worldwide, 71 of these are bee-pollinated. In Europe alone, 84% of the 264 crop species are animal- pollinated and 4 000 vegetable varieties exist thanks to pollination by bees5. The production value of one tonne of pollinator-dependent crop is approximately five times higher than one of those crop categories that do not depend on insects6. Has a “pollinator crisis” really been occurring during recent decades, or are these concerns just another sign of global biodiversity decline? Several studies have highlighted different factors leading to the pollinators' decline that have been observed around the world. This bulletin considers the latest scientific findings and analyses possible answers to this question. As the bee group is the most important pollinator worldwide, this bulletin focuses on the instability of wild and managed bee populations, the driving forces, potential mitigating measures and recommendations.