Creepy Peepers: The Science Behind Trippy Fly Eyes

Macro of a horsefly with dewdrops on its eyes
(Photo: Attila Fodemesi/Shutterstock)

Complex, compound eyes

The mesh-like appearance of insect eyes is endlessly fascinating — for anyone who can stomach the macro view. So different from our own, insect eyes are compound eyes, meaning they are made up of lots of tiny components. The honeycomb-like cornea of an insect eye is made up of several lenses that all connect to the core of the eye. Just as the human brain interprets upside-down images colored by refracted light, insect brains interpret images from each of these lenses, all working together to form the larger picture of what's in view.

Despite all the data that insect eyes collect and their superior ability to sense motion, they are limited in how far they can see, and only some insects can see color (like butterflies and honey bees, which need to know whether a flower is freshly-bloomed or dying). "For a mosquito to have the wide distance of vision we have, its compound eyes would need to be roughly three feet wide," Molly Kirk and David Denning of BioMedia Associates write in their article about insect eyes.

Each of the millions of insects on Earth has evolved its own way of perceiving the world — and that affects how we perceive them. Here are some of the strangest and most colorful insect eyes to be found in nature:

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Macro photo of a stalk-eyed fly
(Photo: Parkpoom Photography/Shutterstock)

Imagine seeing through the extended eyes of the stalk-eyed fly! These funky-looking bugs can extend their eyes outward by filling their heads with air as they make their final transformation from pupa to adult (see this amazing process in this Discovery "Life" video). While it seems as though these outward-facing eyes might provide superior vision, the main purpose is to attract female flies.

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Macro photo showing the blue-green eyes of a dragonfly
(Photo: smkybear/Flickr)

Dragonflies knock most other insects out of the park when it comes to their vision — and it's no surprise, with those huge globe-like eyes. They can see their prey several feet away and process images with lightning-fast speed.

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Macro image of soldier fly
(Photo: Parkpoom Photography/Shutterstock)

Colored eyes, like those of the soldier fly above, serve a specific purpose in insects: they narrow down the information being processed by each of the tiny lenses. Some insects with metallic-colored eyes have layers and layers of lenses that reflect light, lending an iridescent quality.

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Band-eyed drone fly
(Photo: Alessandro Musicorio/Flickr)

The band-eyed drone fly is a bee mimic, and it takes the ruse to the limit, with stripes even on its eyes. But why? Scientists hypothesize that it affects what this insect sees — definitely a subject for further research.

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An insect that appears to have cross shapes in its eyes
(Photo: Gio Diaz/Flickr)

This fruit fly has a peculiar cross shape in its eyes.

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Macro photo of a deer fly
(Photo: StevenRussellSmithPhotos/Shutterstock)

This deer fly has a distinct pattern on its eyes. In fact, their genus, Chrysops, translates to "gold eyes."

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This blue-eyed dragonfly has a happy look
(Photo: Olgierd Rudak/Flickr)

This dragonfly's eyes are colored to look almost humanlike!

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Horse fly with strange eyes
(Photo: Mikhail Melnikov/Shutterstock)

The common horse fly may seem an ugly nuisance from far away, but in the macro perspective, its eyes draw you in.

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