Insects are known to approach light sources. I know that they use it as navigation tools, by maintaining a constant angle between their path and the light beam. However, if a light source is exceedingly bright, I mean like "blinding" bright, would an insect still use that as navigation tool?

What I have been thinking is, the insect wouldn't use it, and try to escape from the light source. I believe this because the extreme blindness may cause the insect to damage it's eyes, although I am neither knowledgeable nor capable of confirming this.

Such a thing usually doesn't happen in nature, so I'm unsure if such a test has been made before. Nontheless any help would be great. I also understand that my definition of "bright" isn't well defined, since I don't know the maximum intensity an insect can handle. I also haven't mentioned the insect, so for consistency sake, assume it to be a Black Witch moth (Ascalapha odorata)


Would an insect use a light source that's exceedingly bright to navigate?

  • 1
    $\begingroup$ Here's a study that addresses methods for pest control using various light parameters. Though it doesn't explicitely state it, the study does say that intensity is used for both attracting and repelling insects that are photoreceptive. rd.springer.com/content/pdf/10.1007/s13355-013-0219-x.pdf $\endgroup$
    – user22020
    Commented Aug 10, 2017 at 18:57
  • $\begingroup$ "Insects exhibit the following phototactic behaviors: (A) attraction (i.e., positive phototaxis, moving toward a light source); this response can be used to trap pests, but the effective wavelengths and intensities vary among species and (B) repulsion (i.e., negative phototaxis, moving away from light); this can be used to prevent pests from entering a cultivation area by presenting light at wavelengths and intensities that repel them." $\endgroup$
    – user22020
    Commented Aug 10, 2017 at 18:58
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    $\begingroup$ First, your assumption that insects use light as navigation might be wrong, the flight-to-light behaviour is still far from understood. Link. Secondly, I doubt a light can be too bright. The incandescent lights that are often used for trapping them are so bright that human are blinded by them. $\endgroup$
    – RHA
    Commented Aug 10, 2017 at 19:59


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