Effects of replacing outdoor lighting with white LEDs with different correlated color temperatures on the attraction of nocturnal insects

Currently, many sources of outdoor lighting are being replaced with light-emitting diodes (LEDs). Although conventional light sources that emit light in the ultraviolet range are generally more attractive to nocturnal insects than LEDs, which typically do not emit ultraviolet light, it has not been established whether there are differences in attraction to white LEDs that differ in correlated color temperature (CCT). We experimentally compared the attraction of insects to fluorescent mercury vapor (MV) lamps and white LEDs with two different CCTs (5000 and 2200 K) using custom-made flight intercept traps in Hiroshima Prefecture, western Japan. Although the attraction of lepidopterans and coleopterans to white LEDs was approximately 85-90% lower than that to MV lamps, hemipterans, dipterans, and hymenopterans were found to be almost equally attracted to the 5000-K LEDs and MV lamps. Our results suggest that spectral tuning of LEDs can affect the attraction of insects belonging to various orders, including Coleoptera and Hemiptera, although we did not find a significant difference between the two LED types with respect to the attraction of moths or flies. These findings indicate that the effects of converting outdoor light sources can be reduced by customizing spectral compositions.