Towards a mechanistic understanding of the effects of artificial light at night on insect populations and communities

Artificial light at night (ALAN) is markedly changing the night-time environment with many studies showing single-species responses. Exposure to ALAN can lead to population declines that should have consequences for the functioning and stability of ecological communities. Here, we summarise current knowledge on how insect communities are affected by ALAN. Based on reported effects of ALAN on the interactions between species, and what has been demonstrated for similar effects in other contexts, we argue that direct effects of ALAN on a few species can potentially propagate through the network of species interactions to have widespread effects in ecological communities. This can lead to a shift in community structure and simplified communities. We discuss the diversity of ALAN as a pressure and highlight major gaps in the research field. In particular, we conclude that landscape level impacts on populations and communities are understudied.