Impacts of artificial lighting at night on insect conservation

The widespread adoption of artificial lighting at night (ALAN) presents a growing threat to biodiversity in general and nocturnally active insects in particular. ALAN may be contributing to widely reported declines in insect populations but supporting evidence is sparse. Recent advances in external lighting technology, particularly the increasing adoption of broad spectrum 'white' LEDs, suggest that impacts of ALAN on natural systems are likely to increase. This special issue of Insect Conservation and Diversity presents some of the recent research addressing the impacts of ALAN on insects and their conservation. The papers cover (i) reviews of existing literature, (ii) results from experimental studies of impacts of ALAN on insects, from individual species to communities, (iii) priorities for future research, and (iv) best practice recommendations for designing future experimentation. Collectively, the papers illustrate a vibrant and expanding field of enquiry. In addition to further studies of effects at the individual insect level, future research priorities will need to address how ALAN affects long-term population dynamics, the composition of insect communities and ecosystem services. A major challenge will be to devise novel ways to minimise the adverse effects of ALAN which can be used to inform conservation interventions. Various mitigation strategies are available, including modification of the spectral composition of lighting, dimming, shielding and controlling illumination using timers and motion sensors, but require customisation for particular species and situations.