Towards public LED lighting with minimal impact on insect movement

Over the last decades, a decline in insect populations has been observed. Public lighting infrastructure is both expanding to previously unlit areas, and already existing infrastructure is being replaced by LED lighting. Consequently, there is a growing imperative to investigate the impact of artificial light at night (ALAN) on nocturnal insect communities. As the correlated colour temperature (CCT) of LEDs is a customisable industry standard, this paper studies its impact on the abundance of attracted nocturnal insects. Data were collected using three LED light sources, each switching subsequently between 2700K and 6500K, with a similar luminous flux of 6696 lm and 7440 lm, respectively. A vertically positioned white surface gathers attracted insects and facilitates the image-based assessments. Observations during a pilot experiment of four nights in the Belgian Famenne-Ardenne region currently show that the number of attracted insects was 13% higher at 2700K than at 6500K. Broader tests across a wide range of ecosystems and light characteristics will be performed to confirm to which extent these results may be generalized and can inform the development of insect-friendly lighting.