(50,000) Windows to the soul

One of the things I find most interesting about all insects, and not just this highly cooperative grasshopper that I happened upon while walking a tomato field a bit ago, is their compound eyes. We say that these are compound eyes because each is composed of thousands of photosensitive units called ommatidia (the diagram shows 15 of these forming part of the surface of the eye). Light enters each ommatidium through a cornea (labeled lens in the figure) and this is focused by the crystalline cone into a beam which enters a narrow tube called the rhabdom. The rhabdom is surrounded by retinula cells that generate electrochemical signals which pass along axons which are bundled to form the optic nerve, and this forms a direct connection to the brain. Contrary to popular belief, insects do not see a myriad of repeated images, akin to the wall of flat-screen televisions one encounters upon entering any well-supplied electronics store. Instead, each ommatidium forms an image of one tiny region of the animal’s visual field; all of these are then processed to represent the immediate visual environment. Because the cornea is fixed and cannot be focused, the resulting image isn’t highly resolved (the image of an insect’s view-of-the-world included below shows a stream, a near shore and a distant treeline). This arrangement is best suited for discerning movements as they occur across areas of contrast. The eyes of a horsefly, however, each with 50,000 ommatidia, can form a much more detailed picture of the world. Notice also that the grasshopper has a dark spot in the shallow depression between the antennae and also a spot between the right antenna and the right eye (there is a corresponding one on the animal’s left which is obscured by the antenna there). These are also organs of photoreception, ocelli, which are not as complex as the compound eyes and the function of which is limited to the discernment of light and dark. Finally, the title to this post begs the question of whether insects have a soul. I’ll get back to you on that one.

14 thoughts on “(50,000) Windows to the soul

  1. I love compound eyes – I think they’re fascinating. You may already know about the astronomers who developed the dragonfly telescope using Canon lenses — $100,000 worth. It’s a fascinating tale of a couple of guys who made the leap, and built what many of our insects already have. Now, that’s soulful.

  2. Now, you see, whenever grasshoppers are mentioned, all I can think of is the wise old Green Grasshopper in the children’s book James and the Giant Peach by Roald Dahl. I’m sure he had a soul …

  3. Aye, indeed the question of souls. A long time ago I did wonder about a more functional definition of one. Upon reading Dan Dennet’s attempt to explain consciousness two decades ago or maybe a bit more, it occurred to me that (1) you can be completely full of s__t and still make it sound good and (2) there were some questions that science is still unable to address directly, at least with a functional approach. Maybe some day, but not under our current mind-sets. On a more interesting note, the more excited I became about the possibility that maybe with the current level of precision we can apply to the manufacturing process that someone might take to inventing an optical sensor system based on the compound eye approach. Think about it – a couple of million sensors, each with its own lens mounted on a 1-inch surface. With the appropriate software for making sense out of the sensor data you’d have quite a dandy digital imaging system. Hmmm – maybe that’s how we should all make the gazillion dollars we should be.

  4. The grasshopper does ineed look ‘as if it had a soul’ – I mean it looks as if it has a unique personality … like the insects in animated cartoons! Having said that I realize that the amusement value of such movies is due to the contrast between the cartoon animals and their real-live counterparts, often considered more close to little robots that follow simple rules. But on the other hand (AFAIK) sociological research has shown that a large crowd of humans act – on average – also in quite predictable ways. So we should probably not feel too superior to ants and bees.

  5. That was an interesting question about the insect soul… looking forward to what other readers might say. I remember the childhood cartoons that showed us the vision of the world through a bug’s point of view. They usually included the “wall of TVs” experience. I have to be honest, and say I never thought to question it, but it wouldn’t make sense for such a small-brained animal to have such a complex field of vision. The grasshopper shot is amazing; how did you manage it? I find insects are incredibly difficult to photograph; they move too quickly.

    • Thanks M. I don’t know why this particular individual chose to pose for me, but sit still it did … for perhaps a minute. I was glad for it because the depth-of-field was such that I took a couple dozen shots to allow for one or two in good, sharp, focus. It’s always a balancing act … if you spin up the ISO, you gain speed and depth but lose overall sharpness. If you dial down the ISO you gain sharpness but lose the speed and depth. And, I’m not a fan of the flash. If you care to look at Steve’s comment I think you’ll agree that he makes a reasonable observation. If indeed we can all trace our lineages back to some single, primitive, form … if, genealogically-speaking, we are all related … then why would only a very select few of us have a soul while others did not? What’s a soul anyway? I wrote in my reply to Steve that I am always very careful when writing about and expressing my opinions on such matters for fear of turning off readers who might be offended by my positions on such matters. I do not hold Homo sapiens in any special regard. There is no doubt that our brain sets us apart from the rest of the animal kingdom, but I see no reason that that should make us special in any higher sense. No … if someone, someday, is able to define the soul, quantitatively, and point to it, empirically, then I will agree it exists. And, if it does exists … then a grasshopper has one too! Have a great day. D

  6. It figures a horsefly would have good vision so it can find a nice soft spot to nip a bit of flesh. Why wouldn’t an insect have a soul if the human animal does? As we are all descended from a tiny organism that wandered out of the briny sea, assuming one believes in evolution which I do, at which point would a soul have evolved in a human and not anything else? 🙂

    • I’m with you on that one Steve. Evolution has always been one area of my professional (and personal) interest. I agree with your analysis entirely. That being said, I am always mindful of writing about subjects which might turn some of my readers off … if you know what I mean. I have touched upon the topic, here and there, but always very lightly. I think, however, that those who follow this blog know where I’m coming from. Also … I still don’t see the turtle in your post … unless what you really mean is that you see no actual turtle but rather a ‘turtle’ which is really a piece of a tree limb that looks like the real thing. And, finally, did you say that the leafy background is all reflection? If so, I can’t get my mind to see it. I see the blurred leaves as a bushy perimeter of the pond. Anyway … we’ve got pea-soup for weather this morning, I hope you’re doing better than that. D

      • Same here, David. I rarely touch upon religion or politics either on the blog or other social media. No one will change their mind based on my opinion and it may just chase them away.

        Correct … it is not a real turtle … just a lump of wood that plays one on TV. That’s from a commercial that you may have never seen … “I’m not a real Doctor, but I play one on TV.”. 🙂 Yes, that is what the leaves are … except that you are seeing their reflection. The upper ones just seem to be actual as the water was more calm near the shoreline.

        When I left the house this morning, I could barely see where I was going in the neighborhood. The fog thinned out as I got away and then there were pockets of the soupy stuff for the next 10 miles or so. I hope you are now having a bright sunny day.

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