Data processing nightmare - Whirligig Beetles

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NikonUser
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Data processing nightmare - Whirligig Beetles

Post by NikonUser »

Image
Beetle, Family: Gyrinidae; probably Gyrinus sp. Length: 7mm
Habitat: pond surfaces.
Note the 2 body halves each with its own set of compound eyes.
How do they handle seeing one set of images from the the air above the surface and another set of images, perhaps simultaneously, from the water below the surface?

Image
Head close-up, yes those ventral convexities are compound eyes.

Image
These beetles are the ultimate in "slipperyness", nearly impossible to pick up. So how do the males hold onto the females? With octopus-like suction cups on their front feet.

Stacked images but, unfortunately, data not recorded.

EDIT: title changed
Last edited by NikonUser on Mon Oct 13, 2008 12:25 pm, edited 1 time in total.

Graham Stabler
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Post by Graham Stabler »

Beautiful, such an amazing sheen.

It's hard to imagine what looking through the eyes of any insect would be like, the nearest I have found is looking at a mirror ball above an ice hockey match. It gives a low resolution directional view of the action, but four sets of eyes, who knows.

Graham

P_T
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Post by P_T »

Oh wow... that's amazing! Excellent lighting as well, you managed to bring out all the details of the "skin".

If you don't mind telling me, how did you set up your lighting?

You know, the skin texture reminds me of Alien (you know... Ridley Scott, James Cameron).

Harold Gough
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Post by Harold Gough »

A suggestion:

As they are processing dozens of individual images from the compound eye anyway perhaps splitting into two subgroups is a minor additional task. Assuming one set to be corrected for functioning in air and the other for in water, perhaps the beetle would give priority to the upper ones when on the surface, with the images focused. When under water the image from the upper pair would be defocused and ignored.

Harold
My images are a medium for sharing some of my experiences: they are not me.

Cyclops
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Post by Cyclops »

Absolute stunners there!
Canon 30D | Canon IXUS 265HS | Cosina 100mm f3.5 macro | EF 75-300 f4.5-5.6 USM III | EF 50 f1.8 II | Slik 88 tripod | Apex Practicioner monocular microscope

rjlittlefield
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Post by rjlittlefield »

Excellent pictures, NikonUser -- easily the best I've ever seen of this subject. :D
It's hard to imagine what looking through the eyes of any insect would be like, the nearest I have found is looking at a mirror ball above an ice hockey match. It gives a low resolution directional view of the action
Great analogy.

The standard cartoon picture of "Life as seen by a fly" shows a bunch of small high resolution images, one per facet, and you're left to wonder how the fly could possibly put all that information back together again.

The reality is that an insect's retina is conceptually not very different from ours. They are both curved 2-D arrays of photoreceptors on which a single image of the world is projected.

The difference is in the optics. We use a single large wide-angle lens that covers the whole array; the bugs use a bunch of tiny narrow-angle lenses, one for each photosite. Each photosite resolves little or no detail, just brightness at that point in the array.

This beetle probably sees the world a lot like I do through my hard-line bifocal glasses. The visual field is just split into two pieces with something of a gap between them. No harder to handle than looking through a split-paned window, or at a piece of a desktop through a magnifying glass.

--Rik
Last edited by rjlittlefield on Mon Sep 08, 2008 8:11 am, edited 1 time in total.

NikonUser
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Post by NikonUser »

Graham, P_T , Cyclops, and Rik: thanks for the nice comments.

P_T: I will post a separate thread regarding lighting set-up

Harold: These beetles live on the surface, I have never seen one actually submerge. The lower (actually front) edge of the elytra, the sharp edge between the abdominal tergites and sternites, and the lower edge of the antennal sockets are right at the water/air interface. This means than the upper eyes are well into the air and the lower eyes are below the surface with their tops just at the interface (last image). Thus it seems that they are always seeing objects above the surface and below the surface simultaneously. Maybe that's why their swimming is so erratic - hence the name Whirligig Beetles.
They occur in Europe and North America and are usually common.

Harold Gough
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Post by Harold Gough »

While they spend most of their time on the surface they will dive for cover!

http://www.plantpress.com/wildlife/o221 ... beetle.php

Harold
My images are a medium for sharing some of my experiences: they are not me.

DaveW
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Post by DaveW »

With humans the sharp focus is in the centre of our eyes, our peripheral vision tends to detect motion which we then focus on. Maybe these insects work the same in that their brain concentrates on what they are looking at unless their alternative vision detects motion, whereupon their sharp vision is switched to that?

DaveW

lauriek
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Post by lauriek »

Nice shots!

I guess however many compound eyes, oceli and ommitadae a bug has, it's brain is wired to use them properly!

One of my favourite bugs (well buggish creatures) is those little jumping spiders, they must have 360 degree vision with two eyes on the back corners of the head, together with excellent (hunters) stereo vision at the front with the big front two eyes, plus two bonus front eyes nearer the side. (plus another two somewhere I guess, don't spiders have 8 eyes generally?) Plus I've read they can see into the UV spectrum as well.

I reckon the visual bit of the human brain would overload if you somehow fed all that data into it, but the little spiders brain is optimised for it! :)

Jbailey
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Post by Jbailey »

Excelent photos! They remind me of Sci-Fi war vehicles or body armor.

Jim

Harold Gough
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Post by Harold Gough »

The standard number of eyes for a spider is eight. Generally, within a species/individual, they are of a moderate range of sizes. Their arrangement may be a taxonomic character.

Harold
My images are a medium for sharing some of my experiences: they are not me.

NikonUser
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Post by NikonUser »

Posted a ventral shot
HERE

beetleman
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Post by beetleman »

Simply incredible photo. I agree with Rik, it is the best photo I have seen of a Whirligig Beetle and the detail in both photos is excellent.
Take Nothing but Pictures--Leave Nothing but Footprints.
Doug Breda

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