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As everyone knows, I have a swarm trap! I'm hoping to capture a capture, as I did last spring:

  • But I'm worried about the light from the camera LEDs disturbing the bees.
    • According to the infallible intarwebs "Bees, like many insects, see from approximately 300 to 650 nm." and "can’t see the color red:"
    • https://news.ncsu.edu/2011/07/wms-what-bees-see/
    • My cameras are most likely using 850 nm LEDs:
    • https://ellipsesecurity.com/2018/05/850nm-vs-940nm-ir-illuminator/
    • I can definitely see visible red from the front of the camera when the "night vision" feature is on, so they're unlikely to be 940 nm LEDs.
    • So 850 >>>> 650, so I should be safe. Except that I don't know how hard the cutoffs are at 850 nm and 650 nm.
    • My human eyes are allegedly good out to 740 nm
    • https://en.m.wikipedia.org/wiki/Visible_spectrum
    • But I can definitely see my "850 nm" LEDs, so they definitely have some visible output
    • Or my "740 nm" might be a "half max" point or some other arbitrary definition of a soft cutoff.
  • Does anyone have a gut feel for whether a bee would be able to see an 850 nm LED? The interior camera is lit, all the time, and I don't want that to turn the bees away from my trap.
  • I may even want to add a 3rd, side view, and capture a comb-building time lapse like:
  • Does anyone think bees would react to an occasional visible strobe?
 

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First, I can't wait to see your pictures!

But secondly, you have just confirmed everybody's idea of life in California, where even the bees are actresses just waiting to be discovered and get their shot at fame and fortune in the movies.

My problem-solving suggestion about the lights (I have nothing to offer you about dealing with 10K starlets and their 10K greedy agents, not the mention the swarm queen's whole entourage, with her publicist on speed dial) is to see how your current bees react to the lighting. Do they get agitated, ignore it, mob it, dive-bomb the hand holding it, etc. ? I have had very mixed results using a red-gelled flashlight.

Nancy
 

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Just an empirical observation, when I do work in or around the bees after dark I wear a red led headlamp. No indication they see any of the light but it does seem there is something about the LED bulb itself they can pick up on. Initially I thought the few flying around my face might be from the CO2 but they will move toward the headlamp if I remove and hold it away from my body. No idea of the nm of the headlamp and the bees reaction is nothing compared to a white light but there is something they can at least minimally pick up on.
 

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With what you are describing the IR LED's may have a wide fwhm (https://en.wikipedia.org/wiki/Full_width_at_half_maximum). Without having the full specs on the LED's it is hard to say what they actually are.

A quick search found one (of 2 I looked at) with a tail that goes down to about 750 nm. (https://katalog.we-online.de/led/datasheet/15400585A3590.pdf)

My recommendation would be to place a filter in front of the camera to block the lower wavelengths. A quick search found this filter which should cut off at about 790 nm. https://www.adorama.com/le87cp3.html This is a wratton type filter. There isn't much data on the link above, but it is cheap enough it may be worth trying. You may be able to find similar filters elsewhere. See this table for more information on wratton filters. https://en.wikipedia.org/wiki/Wratten_number

If you want me to explain anything more about optics let me know. I occasionally work with optics at work and have an understanding of the basic.
 

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Discussion Starter #7
A quick search found one (of 2 I looked at) with a tail that goes down to about 750 nm. (https://katalog.we-online.de/led/datasheet/15400585A3590.pdf)
You're better at searching than I am! That's the first output curve I've seen, and that was exactly what I was looking for.

Someone sent me a private message with this info:

850 nm is simply too low an energy for a photon to break any kind of chemical bond. Thus no animal can have vision at this wavelength. It is forbidden by the laws of energy as vision depends on a chemical change caused by absorption of signal photons.
I wonder what the lower bound on this is, wavelength-wise.
 

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You're better at searching than I am! That's the first output curve I've seen,
Looking at the filters on digikey they classify IR as above 720 nm peak. If you want you can mess with the filters and look at different LED's and data sheets.
https://www.digikey.com/products/en...ColumnSort=1000011&page=1&stock=1&pageSize=25

Digikey is a large electronics distributor that is easy to search. Most (not all) manufacturers should have a spectral curve for the LED's that they are selling.


if you are interested a curve for the 87c wratten filter can be found under the technical images here. The one above is probably a bit different because it is cheap, but this will give you an idea.
https://www.edmundoptics.com/p/87c-kodak-wratten-infrared-filter/11236/



I wonder what the lower bound on this is, wavelength-wise.
I have no idea. Most of my experience is with instruments and not living things.
 
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