Why do moths head towards the light?


It may be about reproduction. It is hard to find a mate, especially in the dark. Individuals that congregate at lights may have an evolutionary advantage by being able to find a mate that is also congregating at the light. Many insects are attracted to lights: moths, crickets, some flies, etc…

I thought it had something to do with Mach bands.

I’m wondering if it could not so much be the moon itself, but they were originally attracted to reflections of the moon off water before the advent of electricity… like lakes and puddles. If nothing else, it would be a way for two lonely moths to find each other in the night-- not to mention a more likely spot for flowers and food.

Ahhh… a bunch of laymen taking blind stabs at a question they just read about. That’s the scientific way!

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Flies head towards light, too. If I want to take care of an annoying fly, I turn off all the lights, except for the room with the fly swatter or door to the outside. They are trying to leave a dark cave.

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I’ve always thought that maybe insects were hard wired to think of bright lights in darkness as “exits” and that they were trying to get “out”.

Maybe. Particularly when hatched at birth, flying to the light would be beneficial. It makes me wonder if there are similarities with deep sea creatures who are also attracted to light.

Edit: Stupid mobile version of youtube is stupid.

occam’s razor would indicate this is a lot more likely than navigation by moon or any reproductive reason.

it just seems fundamental to all life, though. the sun is a prerequisite for life, after all. like, if most types of animals on earth were in a room filled with pure nitrogen and there was a hose in one corner trickling out oxygen, all the animals would end up over by the hose. granted, that’s more out of necessity than needing light, but my point is that the animals would be about as conscious as to why they were going toward the hose as they are about going toward light–it’s just what you do, y’know?

/blind stab

Personally, I think they are trying to find the darkest place, which would be directly on the other side of the light. But, then when they get to the other side, they repeat…

I was under the impression all moths were fervent evangelical Christians nightly enacting their transmigration to the afterlife.

Well that’s kind of what I was thinking. You don’t have to be Christian to “walk into the light” - it’s an interfaith thing. But the implication worries me: that all moths are dying at all times. How can this be?

I’ve heard this, as well.

Also: “YEEAAGH! A MOTH! Aaahhh…” That’s how it goes in our house.

The way I see it it’s kind of like a lepidoptera passion play. Also, if you talk to any evangelical moth he/she will tell you only moths who have accepted Moth Christ as their Lord and Personal Savior™ can expect the glory of Heaven in the Afterlife.

Maggie, thanks for another neat story! I’ve debated this very point with fellow entomologists before. It might be better to call these guesses “hypotheses” rather than theories (it has a special meaning in science and allows some to dismiss evolution as “Just a theory”.

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