Artificial light is rightly considered a major social, cultural and economic achievement. Yet artificial light at night is also said to pose a threat to biodiversity, especially affecting nocturnal species in metropolitan areas. It has become clear that the response by wildlife to artificial light at night may vary across species, seasons and lamp types. A study conducted by a team led by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) sheds new light on how exactly ultraviolet (UV) emitting and non-UV emitting street lamps influence the activity of bats in the Berlin metropolitan area and whether tree cover might mitigate any effect of light pollution. The study is published in the scientific journal Frontiers in Ecology and Evolution.