Impact of artificial light on the distribution of the common European glow-worm, Lampyris noctiluca (Coleoptera: Lampyridae)

Abstract

The influence of artificial light on fireflies is often discussed. Specialists agree that the normal mating behaviour of fireflies is disturbed by artificial night lighting. The effects of artificial light on the behaviour of the common European glow-worm, Lampyris noctiluca, are not well understood. Males of L. noctiluca, which can fly but do not glow, are attracted to glowing, flightless, larviform adult females, and are easily caught by simple light-emitting diode (LED) traps. LED traps were placed in illuminated and dark areas (under and between street lights, respectively) in a residential quarter of the village of Biberstein in Switzerland. On nights when the street lights were on, the LED traps attracted males only in dark places, while traps under the street lights stayed empty. In contrast, on nights when the street lights were switched off, males were trapped both between and under the lights. This indicates that artificial night light interferes with the ability of males to locate females, or that males avoid illuminated areas. Night lighting, however, had no apparent influence on the spatial distribution of glowing females during the last six summers (2004–2009). Females displayed both under the lamps and in the dark areas bordering the path surveyed. As females normally do not move from their display sites, those displaying under street lamps may die without mating. Artificial night lighting may, therefore, cut ‘cheese holes’ in the mating landscape of glow-worms.