The globally increasing light pollution has negative effects on organisms and entire ecosystems. The consequences are especially hard on nocturnal insects, since their attraction to artificial light sources generally ends fatal. A new study by Swiss zoologists from the Universities of Basel and Zurich now shows that urban moths have learned to avoid light. The journal Biology Letters has published their results.Some insects are attracted by light while others shy away from it. Proverbial is the attraction light has on moths. Street lamps and other artificial light sources often become death traps for nocturnal insects such as moths. Either they die through direct burning or through increased exposure to predators. Mortality of urban insects can thus be 40- to 100- fold higher than in rural populations.