Blinded by the Light: Artificial Light Lowers Mate Attraction Success in Female Glow-Worms (Lampyris noctiluca L.)

SIMPLE SUMMARY: Nocturnal light pollution is a worldwide growing problem, threatening nocturnal biodiversity. We studied the impact of streetlights on mating success of the female common glow-worm, a bioluminescent nocturnal beetle (Lampyris noctiluca L.) that uses light signals for sexual communication. We monitored individual females daily and assumed that when they stopped glowing, they had effectively mated. We found that females in dark surroundings typically stopped glowing after one night, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous hypotheses that females exposed to artificial light suffer from a reduced mate attraction success, which can lead to population declines. Our findings represent valuable information that can be used by policy makers and managers to conserve the iconic glow-worms. ABSTRACT: Nocturnal light pollution from anthropogenic origin is increasing worldwide and is recognised as a major threat for nocturnal biodiversity. We studied the impact of artificial light on the mate attraction success of female common glow-worms (Lampyris noctiluca L.) by daily monitoring their glowing status in the field, acting as a proxy for mating status throughout the mating season. We found that females in dark surroundings typically stopped glowing after one night, indicating that they had mated, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous findings and hypotheses that females exposed to artificial light suffer from a reduced mate attraction success with a negative impact on populations.