If you are a fish and want to watch TV, this might be the invention for you.
Researchers from the University of Queensland have developed an ultraviolet “television” display specially designed for fish. This could help them learn more about how fish and other animals see the world, they suggest in their paper, published in Methods in Ecology and Evolution.
“We affectionately call it the ‘UV-TV’, but I doubt that anyone would want one in their home!” says study leader Samuel Powell.
Display monitors such as TVs or computer screens have previously been used in animal studies to learn how subjects react to a visual stimulus. But these are suited to human eyes and not all animals see the same wavelengths.
“Human TVs generally use three colours – red, green and blue – to create images, but our newly-developed displays have five, including violet and ultraviolet,” says Powell.
“Using this display, it’s now possible to show animals simple shapes, or to test their ability to tell colours apart, or their perception of motion by moving dot patterns.”
This is a big step forward to learning how fish and other animals react to particular patterns, but you won’t be watching Finding Nemo with your pet goldfish yet – the TV’s not just low res, it comes with a health warning.
“You’d have to wear sunglasses and sunscreen while watching it, and the resolution is quite low – 8 by 12 pixels in a 4 by 5 centimetre area – so don’t expect to be watching Netflix in ultraviolet anytime soon,” says Powell.
“This very low resolution is enough to show dot patterns to test fish perception in what’s known as an Ishihara test, which would be familiar to anyone who’s been tested for colour blindness.
“In this test, humans read a number hidden in a bunch of coloured dots, but as animals can’t read numbers back to us, they’re trained to peck the ‘odd dot’ out of a field of differently coloured dots.”
The tiny TV is sufficient to learn how fish react to colour patterns in nature. “There are many colour patterns in nature that are invisible to us because we cannot detect UV,” says fellow researcher Karen Cheney.
“Bees use UV patterns on flowers to locate nectar, for example, and fish can recognise individuals using UV facial patterns.”
They are using this to study recognition between particular marine life based on scale patterns, to establish who is the boss.
“We’ve recently started studying the vision of anemonefish or clownfish – aka, Nemo – which, unlike humans, have UV-sensitive vision.
“Our research is already showing that the white stripes on anemonefish also reflect UV, so we think UV colour signals may be used to recognise each other and may be involved in signalling dominance within their social group.
“Who knows what other discoveries we can now make about how certain animals behave, interact and think?”
Key research points:
- Some animals see UV, which is difficult to study
- Researchers developed tiny screen for fish that shows UV
- The ‘UV-TV’ displays patterns and colours
- This research may show how fish reach to visual cures
Dr Deborah Devis is a science journalist at The Royal Institution of Australia.
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