RT Journal Article
SR Electronic
T1 Why flying insects gather at artificial light
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2023.04.11.536486
DO 10.1101/2023.04.11.536486
A1 Samuel T Fabian
A1 Yash Sondhi
A1 Pablo Allen
A1 Jamie Theobald
A1 Huai-Ti Lin
YR 2023
UL http://biorxiv.org/content/early/2023/04/12/2023.04.11.536486.abstract
AB For millennia, humans have watched nocturnal insects flying erratically around fires and lamps. Explanations have included theories of “lunar navigation” and “escape to light”. However, without three-dimensional flight data to test them rigorously, this odd behaviour has remained unexplained. We employed high-resolution motion capture in the laboratory and stereo-videography in the field to reconstruct the 3D kinematics of insect flights around artificial lights. Contrary to the expectation of attraction, insects do not steer directly toward the light. Instead, insects turn their dorsum toward the light, generating flight bouts perpendicular to the source. Under natural sky light, tilting the dorsum towards the brightest visual hemisphere helps maintain proper flight attitude and control. Near artificial sources, however, this highly conserved dorsal-light-response can produce continuous steering around the light and trap an insect. Our guidance model demonstrates that this dorsal tilting is sufficient to create the seemingly erratic flight paths of insects near lights and is the most plausible model for why flying insects gather at artificial lights.Competing Interest StatementThe authors have declared no competing interest.