It turns out that moths don’t continually fly into your porch light at night because they’re attracted to it. They’re actually trying to use it to navigate, but it’s confusing them.
A research team recently conducted a study in a cloud forest in Costa Rica to determine why, exactly, insects appear to be drawn to artificial light sources at night. They set up a light and closely studied the movements of the insects that appeared around it. They then combined this data with lab experiments that recorded the flight trajectories of both diurnal and nocturnal insects.
The results found that rather than flying into the light, the insects were turning their dorsum or back to it. This suggests that they were attempting to use the light to navigate. “Under natural sky light, tilting the dorsum towards the brightest visual hemisphere helps maintain proper flight attitude and control,” the team said in their findings. “Near artificial sources, however, this highly conserved dorsal-light-response can produce continuous steering around the light and trap an insect.”
