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Oh tropical colours - so bright, so vivid, so not




All my thoughts about the wonderful bright colours of the tropics has been blown to bits by current colour research.

The colour of plants, birds, and animals seem so much brighter in tropical regions – like parrots, exotic fruit, hibiscus, frogs and so on. Ecologist Rhiannon Dalrymple from the University of New South Wales in Australia is the first person to test whether the colours of the tropics are really so bright, so vivid (Global Ecology and Biogeography, Canberra Times, September 25, 2015).

Dalrymple maintains that tropical species are not more colourful than plants and animals living further from the equator. On average, she said, tropical species were less colourful than temperate species. Now that is surprising!

For the experiments, Dalrymple used a spectometre machine to measure the intensity of colour of more than 500 species of birds, more than 400 species of butterflies, and more than 300 plant varieties. She also measured the UV colour levels that humans cannot see, but which are visible to animals.

Supervisor of the research, Angela Moles, said early explorers often collected the most interesting and colourful plants and animals from tropical regions mainly because they could be sold to museums and collectors for more money. This is probably why we first believed that tropical species were more colourful. There was a collection bias. 

Over the years, as more people visited tropical locations, it did seem that the light and heat produced extraordinary plants and animals with brighter plumage or skin. However, it’s only now that the colour intensity has been tested that we find that there is no link between the heat and light in the tropics and the coloured feathers, fur, hide, scales, iridescence, or skin of tropical species.






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