cross-posted from: https://lemmy.dbzer0.com/post/14539490
The bugs around the streetlight are being tricked to think they are going in a straight line. They are doing the aerial equivalent of an ant death spiral.
Preexisting research into bugs circling lights was mainly to see what properties of the lights attracted the bugs, which is how we know that certain LED lights can prevent the bugs from flying towards it.
This study, however, showed that the bugs aren’t trying to get to the light at all. The light triggers their dorsal reflex, causing them to recalibrate their sense of direction to keep the light at a fixed angle from their perspective. The bugs think they are going in a straight line, forever, and they never get to where they are going.
If you’re in a situation where you need and have outdoor lights, placing them on a timer is an easy way to drastically reduce the negative impact to the surrounding wildlife. Choosing bulbs or using a film to produce yellow or amber light is another way to improve the effort, and can make it safer for people who have to move between the lit area and an unlit one since amber lights reduce effects of night blindness in people.
The old low pressure sodium lights we had in the UK were great on this front. They were about as efficient as LEDs as well but the bulbs got too expensive to make, so the last factory making them in Europe closed down and they mostly disappeared quite quickly.
I reckon they should switch street lights over to monochromatic yellow LEDs, they’d look the same as the old lights and not affect insect populations so much. They’re good for astronomers too as the light is only one wavelength.
