From glow to risk: degree of exposure of Arctiinae moths (Lepidoptera: Erebidae) to light pollution in the Neotropics

Abstract The accelerated decline of insects is driven by anthropogenic pressures such as habitat loss, pesticide use, and climate change. Species vulnerability varies according to their exposure, sensitivity, and adaptive capacity to these threats. Artificial light at night (ALAN) further increases this vulnerability by disrupting nocturnal and crepuscular species, particularly moths. The subfamily Arctiinae is ecologically diverse, exhibits chemical defenses and ultrasonic signaling, and is considered a valuable bioindicator group. Here, we investigate the relationship between ALAN exposure and habitat suitability for Arctiinae moths across the Neotropical region. We analyzed 17,989 occurrence records representing 3447 Arctiinae species, integrating bioclimatic variables and nighttime light data. We quantified the spatial overlap between potential species distributions and ALAN, including light intensity within occupied pixels. All species showed some level of exposure to artificial light, with 24% having more than 50% of their potential range affected. Species with broader geographic ranges exhibited disproportionately higher exposure. Predicted species richness was generally higher in illuminated areas, except in the Pantanal, indicating that regions of high ecological suitability often coincide with urbanized and artificially lit environments. The risks posed by ALAN to nocturnal biodiversity highlight the need for conservation strategies focused on areas with low levels of light pollution. Future studies integrating spatial, functional, and behavioral data will be essential to better understand both direct and indirect impacts of ALAN and to prioritize the conservation of nocturnal species in the Neotropical region.