How do insects react to flash? Is it dangerous for them?

Discussion in 'Nature' started by markus_ehrenfried, Aug 25, 2003.

  1. Recently I started using flash for macro photography. I was surprised
    that insects don't 'react' to the strong light pulse at all: they seem
    not to startle, they behave (to my up to now limited experience) as if
    the strong light wouldn't be there. Watching them after taking the
    photo I have the impression that they behave perfectly normal.

    What is your experience with flash in insect photography? I'm worried
    the insect could be temporarily 'blinded' after the flash (like I'm
    when I look directly into the light). Is there a physiological reason
    that they are perhaps insensitive to strong light intensities of
    millisecond duration?

    I wouldn't like the idea that I do any harm to these little creatures...
  2. You COULD pass out little sunglasses first.
  3. stemked

    stemked Moderator

    A good friend of mine who is an entomologists will be delighted to hear that there are those who are concerned about the welfare of insects exposed to bright light. My experience has been similar. Some fly away (and still are coherant enough to fly properly) or they do nothing. I suspect they are fine. Since you linger around for a few seconds after your photograph any preditors are likely too frightened by you to be thinking about gobbling up a stunned insect before they recover.
  4. Markus,

    Interesting question--one I've been thinking about a lot.

    I was shooting lots of butterflies with flash a few weeks ago during the period when butterflies are warming their wings in the sun. One particular Monarch closed its wings quickly when I shot--appearing to be surprised as if by lightning. I backed away, leaving it in peace. They most certainly *CAN* see the flash, or detect its presence under some conditions. Dozens of others didn't seem to mind at all.
  5. I have done a lot of macro shots of insects using flash. Depending on the species,
    you can get anything from no response to instant flight. In the latter case, I've never
    seen behavior indicative of visual impairment or damage (they seem to orient
    coherently, fly in appropriate directions, do not bump into things, etc.). It is a very
    intense light, but also very brief, so the total photon load is probably not all that
    large. Perhaps for nocturnal species, the problem is more significant.

    Given their need to respond to very short-lived stimuli, I would be surprised if insects
    could not detect millisecond-duration flashes. I suspect they fail to respond (in some
    cases) because the flash isn't perceived as a threat.
  6. Next to bacteria and other microscopic organisms, insects are among the oldest and certainly the most successful life forms on earth, by many trillions. They are both beneficial and distructive to other life forms, and are the exclusive diet of many species including their own. Tomorrow, take a praying mantis to lunch.
  7. What color sunglasses are needed to dim the red focus light (on the Nikon F100) that sometimes 'spooks' butterflies? :]

    ...on the serious side, if direct sunlight does not 'blind' the insect, your electronic flash is not going to hinder the insect's vision.
  8. While photographing insects on cold mornings, I have observed they tend to "warm up" after 5-6 flashes from close range. That's all that I have observed -- there is no noticeable change in behavior in broad daylight when using flash.
  9. lol Art, sunglasses?

    I don't know, but could it be that the lack of IR illumination from an electronic flash cause them not to register the light at all? Do electronic flashes emmit IR?
  10. In my experience, very few animal species (insects or otherwise) react to flash. I suppose their is nothing in an animal's environment that flashes brightly before eating its prey!

    Using flash during daylight hours is likely to have little effect on an animal's visual system. Shooting animals at night with a flash on the other hand will almost certainly cause some temporary visual impairment.
  11. I notice that eye-hunters, like jumping spiders, react quite strongly to a flash. Whether it actually have short- or longer term negative effects on their sight, should be tested in an experimental setup. I guess a setup like that could be fairly simple - I just will not take the time to do the experiments. Any volunteers?


  12. Insects see visual information at frequencies of interrupted light
    far beyond what the human eye can detect. I do not mean the
    wave length of light they can perceive. That range is also much
    broader than what we humans call the 'visual ' wavelengths of
    light (many insects can see in UV and infrared wavelengths as
    well). They do not really 'see' in a way that is anything like the way
    humans see the world.

    Insects can actually see the flickering of incandesent lights,
    which go on and off at 60 cycles per second. Most humans can
    not detect flash frequencies faster than that which is why your
    computer monitor is set at 60 cycles per second or faster. We
    see a continuous image even though it is blinking on and off.
    Insects can see flickering images into the range of thousands of
    cycles per second.

    Just imagine what our brightly lit incandescent nightime world
    must seem like to them. Or our seemingly contiguous movies.
    Blink, Blink, Blink, Blink, Blink...

    We are the real aliens in the insect world, beaming completely
    unatural types of illumination all over the place. Oh, the horror,
    the horror...
  13. From my limited experience, I can say that, yes, they tend to react. The other day, I was experimenting with my flash while trying macro shots of an insect. It co-operated for first few shots, but thereafter, it started to fly away to other branches and leaves. When I followed, it decided to attack me. Flew straight to me and my lens, trying to scare me off. I gave up trying to shoot the little brat and was concentrating on a nearby flower (at least that's a lot peaceful) when that bugger came back once again to attack my camera set up. What an annoying persistent creature. On second thoughts, I could understand, it was thinking the same way about me. :)
  14. This really is a minor nit-pick which I guess is appropriate since nits are eggs
    of lice which are insects...

    That said, insects, for all their fascinating characteristics, can only resolve up
    to several hundred Hz, say 300, not thousands. Some can resolve
    significantly less than 300 Hz.
  15. LOL Edwin! You are correct of course. I was mistaken about the
    frequency response range. Oh well, 300 Hz is still 6 times faster
    than the human eye. I found this somewhere:
    flicker fusion frequency - frequency of light flashes that an
    organism can discriminate. Two types of insects based on the
    number of pulses of light that can be discriminated.

    slow - 20-60 pulses of light/sec
    fast - 300 pulses of light/sec

    This may be important for rearing insects in that some can
    actually detect the individual flicks of fluorescent lamps. Humans
    can detect up to about 40 pulses of light/sec, therefore we are
    able to see movies as if it were live action. Some insects could
    watch a movie and see each individual frame of film!

    But of course in nature there are no films or fluorescent lamps,
    just the sun. But this ability to detect pulses of light is important
    for the detection of objects while flying. In fact, fast flying insects
    have a higher flicker fusion frequency. But also, stationary
    insects can detect faster moving objects.
  16. Brad- That is not true, my brothers ant farm features a multiplex.
  17. The possible harm would take place depending on the distance from the light source, its intensity and its duration. Most of light sources emmit IR radiation and this would be responsible of a burn sensation on skin temperature receptors of the insect. Try to put your hand very tight to a flash (be careful) and you may probably feel a short but intense "burn sensation". I don't mean that flash "fries" the insect, but what I mean is that whenever the insect is too close to the flash, can feel some kind of instant warming. This would be a reasonable explanation of scaring in some cases. Intense or continued flash lightening may cause some degree of dehidration or drying on insect skin tissues.

    Another explanation of getting scared from light flashes would be a "surprise effect", only dangerous if the insect suffers from heart disease (joke). During a storm thousands of insects are amazed by nearer rays, but milion years of evolution have made insects to be used to those natural flashes. Thus a nocturnal photograpic flash would have the same effect on them (insignificant).

    That's what I think about it (regrets for any language mistake, regards from Spain).
  18. Okay everyone, I have a PHOTOGRAPHIC answer to the ultimate question. Check this out!
  19. Hi Stew, that is really a cool picture. Yes, that answers my original question! :) The bad
    thing is: I cannot find on my Canon Macro Flash unit the button to activate those
    preflashes for preventing the red eye effect!

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