September 01, 2002

Autumn Entomology II

Image copyright Fred First

Wow! I never really appreciated that a bee's or wasp's 'face' is mostly EYES! More than 50% of the head of this wasp is it's "two" eyes. Actually, it probably has 5 eyes (including a few simple eyes) in addition to its two compound eyes, which probably like the honeybee, has more than 5000 components called omatidia, each producing a dot on the image map of what the insect actually sees. Here's a little snippet on insect vision that is interesting:

[...]the resolving ability of the honeybee eye is poor in comparison with that of most vertebrate eyes and only 1/60 as good as that of the human eye; that is, two objects that we could distinguish between at 60 feet could only be discriminated by the bee at a distance of one foot.

The compound eye is excellent at detecting motion. As an object moves across the visual field, ommatidia are progressively turned on and off. Because of the resulting "flicker effect", insects respond far better to moving objects than stationary ones. Honeybees, for example, will visit wind-blown flowers more readily than still ones. [...]

I suppose that means the next time I get into a hornets nest, I should just stand still? I don't think I will test this hypothesis. Any volunteers? Anyone?

We were talking about vision at the dinner table last night. I remembered that a man called George Stratton in the late 1800's had worn a pair of glasses that inverted the image, so that everything looked upside down. After 8 days, his brain had adapted to this and he was able to ride a bicycle around town without any problems! Not so surprising, I guess, since the image that the human eye sends to the brain is upside down, and we 'learn' to see it rightside-up.

Since we are a bit off topic here anyway, take a look at this stereogram relevant to our subject. Put your nose very near your monitor and try to look through the screen to the back of the monitor. Then, slowly, move back away from the screen without changing the distant focus of your eye.

Posted by fred1st at September 1, 2002 07:10 AM

I love those magic eye things.....for some reason I get them right off...the key is to stare at it without really looking at it(like you are staring off into space).....then all of a sudden its there and you can really examine it.

Posted by: Eva at September 1, 2002 12:24 PM

The magic eye pictures are so irritating. I can never see anything.

Posted by: Lynn at September 3, 2002 08:40 AM

Hey Fred, you might want to scale down the picture just a tad for the contest. 400 pixels on the longest side.

Posted by: Electrin at September 6, 2002 03:38 AM

Fantastic photo btw.

Posted by: Electrin at September 6, 2002 03:38 AM

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