Behavioural responses of fireflies to artificial light: Red lights attract adult Lamprigera (Coleoptera, Lampyridae)

Artificial lights expanding into natural environments disrupt ecological systems, affecting organisms that depend on natural light cues. Fireflies, which use bioluminescence for communication, are especially vulnerable. Although red light has been suggested as a solution, its effectiveness varies. This study examines how adult male and larval Lamprigera fireflies respond to varying intensities of artificial light at different wavelengths. We conducted field observations on adult male attraction patterns and ex situ studies of larval behaviour. Adult males were attracted to red and warm-white light, whereas larvae showed no response to red light or low-intensity light. Higher-intensity warm-white and cool-white light suppressed overall larval activity, with increasing intensity amplifying negative impacts regardless of spectral composition. Our findings indicate that successful light mitigation strategies for fireflies require balancing life stage-specific responses while maintaining artificial light intensities that minimise ecological impacts yet preserve human visual function.