TY - JOUR A1 - Degen, Jacqueline A1 - Storms, Mona A1 - Lee, Benjamin A1 - Jechow, Andreas A1 - Stoeckl, Anna A1 - Hoelker, Franz A1 - Jakhar, Aryan A1 - Walter, Thomas A1 - Walter, Stefan A1 - Mitesser, Oliver A1 - Hovestadt, Thomas A1 - Degen, Tobias T1 - Shedding light with harmonic radar: Unveiling the hidden impacts of streetlights on moth flight behavior JF - Proceedings of the National Academy of Sciences of the United States of America N2 - One of the most dramatic changes occurring on our planet is the ever- increasing extensive use of artificial light at night, which drastically altered the environment to which nocturnal animals are adapted. Such light pollution has been identified as a driver in the dramatic insect decline of the past years. One nocturnal species group experiencing marked declines are moths, which play a key role in food webs and ecosystem services such as plant pollination. Moths can be easily monitored within the illuminated area of a streetlight, where they typically exhibit disoriented behavior. Yet, little is known about their behavior beyond the illuminated area. Harmonic radar tracking enabled us to close this knowledge gap. We found a significant change in flight behavior beyond the illuminated area of a streetlight. A detailed analysis of the recorded trajectories revealed a barrier effect of streetlights on lappet moths whenever the moon was not available as a natural celestial cue. Furthermore, streetlights increased the tortuosity of flights for both hawk moths and lappet moths. Surprisingly, we had to reject our fundamental hypothesis that most individuals would fly toward a streetlight. Instead, this was true for only 4% of the tested individuals, indicating that the impact of light pollution might be more severe than assumed to date. Our results provide experimental evidence for the fragmentation of landscapes by streetlights and demonstrate that light pollution affects movement patterns of moths beyond what was previously assumed, potentially affecting their reproductive success and hampering a vital ecosystem service. Y1 - 2024 U6 - https://doi.org/10.1073/pnas.2401215121 VL - 121 IS - 42 PB - National Academy of Sciences ER -