why do flies fly around ceiling lights?

They seems to go in squares, for no purpose at all -the light doesn't even have to be on. And it's never the big flies, either, just the smaller ones.

Update:

Actually, I'm more interested why they do it when the light s off; the light being on acting as a beacon I can understand. But they don't fly around other objects in the room -just the light fitting.

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  • Anonymous
    1 decade ago
    Favorite Answer

    They are attracted to lights

    Hi. Insects that fly at night have evolved, over millions of years, to navigate using the moon. To an insect that is flying level with the ground, the moon will *always* appear to be overhead - slightly so, if on the horizon, to almost completely overhead. The moon also moves fairly slowly. Therefore, an insect flying at night that wishes to move in a relatively straight line has only one option: fly so that the relative position of the moon in their visual field stays constant. Can you imagine how this works?

    Now, throw in human beings and their artificial light sources that are even brighter than the moon. When an insect is flying so as to keep the brightest light it sees in a constant relative position, and it sees a small, bright, artificial light, it will fly in a spiral or circle that, over time, gets closer and closer to that light source. So, insects that fly to lights at night usually fly around them in loops, circles, and spirals

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  • 1 decade ago

    It's a point of reference. If you were in a dark field at night and there was a light ..you woud head to it, right ? They often fy around the light fitting, too even when there is no light on. Again, it's a point of reference. If you are a fly..it is your job to fly around... and light fittngs make life easier and safer than flying around in the great unknown.

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  • Bapboy
    Lv 4
    1 decade ago

    You know, this was EXACTLY the question I was going to ask?! Isn't that weird? I've watched the little buggers and they seem to be playing some sort of game. It's like cars around a track. I'm really not sure what it is about the light fitting. It's like they're using it like a planetary body. It's weird. I wonder if anyobdy knows. I'm going to watch this question....

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  • Anonymous
    1 decade ago

    That's a great question.

    I can understand why they fly around a light when it's on, but why they do it when the light is off, I don't know, maybe it's central focal point?

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  • 1 decade ago

    How would you know they are around the light if the light is off?

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  • 1 decade ago

    they are attracted to the heat that the lights emits... Maybe at night, the time when most flies will appear, the weather's is freezing cold. So I think they might need the heat to keep them warm. hehe.. ^_^

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  • Anonymous
    1 decade ago

    they navigate by sunlight, and when it's dark out and the only light is a candle or lightbulb, it throws them into a concentric circle (trying to keep the "sun" at the same angle)... although that could be only moths... but that's true with moths... hope it helped.

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  • 1 decade ago

    flies like light

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  • 1 decade ago

    They are attracted to the light

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  • 1 decade ago

    They are attracted to lights because of their multiple eyes

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