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In this article they are addressing the reason insects are attracted to light when they say

Heat radiation as an attractive component is refuted by the effect of LED lighting, which supplies negligible infrared radiation yet still entraps vast numbers of insects.

I don't see why attraction to LEDs shows they're not seeking heat. Could they for example be evolutionarily programmed to associate light with heat? So that even though they don't encounter heat near/on the LEDs they still "expect" to?

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    $\begingroup$ Do you have any reference to support your hypothesis? Bear in mind that the insects in the article are nocturnal. Until recently the only substantial light at night was the reflected light from the moon - not a lot of infra-red from that. How do you explain that the mechanism you propose might have evolved given the environment they evolved in? $\endgroup$ Feb 15 at 9:40
  • $\begingroup$ @JiminyCricket.My example is only an attempt to provide a logical possibility that shows their conclusion doesn't follow from their premises. $\endgroup$ Feb 15 at 22:49
  • $\begingroup$ Your right to question it, but it doesn't end there. There's a 2016 post here, the first answer might be of interest to you. $\endgroup$ Feb 15 at 23:04
  • $\begingroup$ Then there's the idea that female moths are visually interesting at near-infra-red wavelengths which seems to have some support and there's: Physiological basis of phototaxis to near‑infrared light in Nephotettix cincticeps which suggests limited, but some possibility of (near) IR being visible to some insects. $\endgroup$ Feb 15 at 23:11
  • $\begingroup$ Please be aware that this is a question and answer site, not a journal club for discussion of papers on external sites . Questions should be about biology and of general interest. Your simplistic criticism of a conclusion in a long and complex paper is not that. An appropriate question might be "How are insects attracted to light?". For this reason I am voting to close. $\endgroup$
    – David
    Feb 15 at 23:14

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They're looking for and describing proximate relationships (see e.g. https://en.wikipedia.org/wiki/Proximate_and_ultimate_causation).

If the light isn't warm and insects still move towards it, that means they're not using heat to make the decision where to move. They're not saying anything about the ultimate underlying motives, just the immediate proximate mechanism.

Their alternative model is that it's based on orientation to the sky, by which insects point the top of their body (dorsal surface) toward light; if the sky is bright that would keep them oriented back-upward, but if it's a point source near the ground keeping their back towards the light causes them to fly in circles around the light:

Our guidance model demonstrates that this dorsal tilting is sufficient to create the seemingly erratic flight paths of insects near lights and is the most plausible model for why flying insects gather at artificial lights.

So, if you want to propose heat-seeking as a better hypothesis, you'd need to provide data that would explain why this dorsal facing tilt would make sense for an insect seeking heat.

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  • $\begingroup$ Thank you Bryan! $\endgroup$ Feb 15 at 23:24

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