Light pollution is a growing concern affecting biodiversity, especially moths, which are crucial pollinators. This study evaluates the similarity between artificial and natural light using the Daylight Similarity Index (DSI) and Moonlight Similarity Index (MSI). These indices are then weighted by the visual responses of three moth species: Cydia pomonella, Grapholita molesta, and Lobesia botrana; and Homo sapiens. The study analyzed 193 spectra from LED lamps and compared them to the D65 daylight spectrum and the full moon spectrum.

The results indicate that the maximum similarity occurs at correlated colour temperatures (CCTs) between 3000 and 4000 K, with and without weighting. Higher CCTs are perceived as more similar to natural light by insects. Interestingly, despite their different flight periods, the three moth species did not show significant differences in light perception, suggesting that visual perception mechanisms are more related to family than lifestyle. A slight shift towards diurnal vision was observed in crepuscular species, hinting at a trend towards diurnal vision. This research highlights the importance of considering insect vision in designing lighting systems to mitigate light pollution's impact on moths. Further research is recommended, particularly with UV-inclusive light and other light characteristics, to develop more effective strategies for managing pest populations and protecting biodiversity.