Long-Term Comparison of Attraction of Flying Insects to Streetlights after the Transition from Traditional Light Sources to Light-Emitting Diodes in Urban and Peri-Urban Settings

Roy H. A. van Grunsven,Franz Hölker,Stephanie Peter,Julia Becker,Stefan Heller

doi:10.3390/su11226198

Abstract

Among the different light sources used for street lighting, light-emitting diodes (LEDs) are likely to dominate the world market in the coming years. At the same time, the spectral composition of nocturnal illumination is changing. Europe and many other areas worldwide have implemented bans on energy-inefficient lamps, such as the still very common mercury vapor lamps. However, the impact of artificial light on insects is mostly tested with light-traps or flight-intercept traps that are used for short periods only. By comparing the numbers of insects attracted by street lamps before and after replacing mercury vapor light sources (MV) with light emitting diodes, we assessed the impact in more typical (urban and peri-urban) settings over several years. We found that LED attracted approximately half of the number of insects compared to MV lights. Furthermore, most insect groups are less drawn by LED than by MV, while Hymenoptera are less attracted by MV than by LED. Thus, the composition of the attracted communities differed between the light sources, which may impact ecosystem processes and functions. In green peri-urban settings more insects are attracted than in an urban setting, but the relative difference between the light sources is the same.

Highlights

Illumination of nocturnal landscapes has increased rapidly during the last few decades [1,2] and is considered an important ecological threat [3,4,5]
Different light sources attract different numbers of insects and to a large extent this depends on the spectral composition [8,9,10], several studies comparing the attractiveness of lamp types differing in spectral output have been performed and in general light sources that emit a large amount of UV and blue light attract more insects than light sources that emit mostly longer wavelengths [9,11,12]
In Berlin and Brandenburg, many mercury vapor lights were used until recently and these are being replaced by light-emitting diodes (LEDs). This transition from mercury vapor to LED allows us to assess to what extent the lamp type affects the number and the assemblage of insects attracted to streetlights and whether this depends on the setting, either peri-urban or urban, using actual street lighting in a realistic long-term setting

Summary

Introduction

Illumination of nocturnal landscapes has increased rapidly during the last few decades [1,2] and is considered an important ecological threat [3,4,5]. We are not aware of any study where the insect phototaxis of different light sources in urban and peri-urban areas is explicitly compared.

Results

Conclusion