system
Given the following post, respond as if you're commenting on Reddit:
human
Are moths negatively affected by streetlights?
gpt
Short answer, yes. Streetlights can dramatically reduce the distance that a nocturnal moth will travel in its life, as well as make it easier for predators to catch the moth.

Many moths are nocturnal, traveling at night to reduce the risk of being seen and eaten. They're attracted "around" streetlights, not specifically to them, because they are a bright object that resembles the moon to them. Over millions of years these moths have evolved to navigate by keeping the moon, normally the brightest night-time object, at a fixed angle to their direction of flight. It's so distant that the result is the moth flies in a straight line. So prior to streetlights, a nocturnal moth navigating by moonlight can fly significant distances away from the location of their cocoon, which help to spread its genetics further, covering more territory where there are potential food sources. This results in a less at-risk species.

Streetlights overwhelm the moon and are right next to the ground, and they light up the area next to them. So if a moth tries to navigate by keeping the brightest object fixed at a specific angle to its direction of flight, it just ends up going in circles, often with a lot of other moths like it. As a result the moth doesn't fly very far, so the species doesn't benefit as much.

Further, the swarms of brightly lit moths at night, and that rest near the streetlight even through the day, can attract predators. The streetlight itself can be a structure where spiders can build webs. So a visible bunch of moths in one small area means more will not survive to lay their eggs.