Iridescent camouflage found, according to reports in Science (AAAS) News, ScienceDaily, Telegraph (UK) 23 January 2020 and Current Biology 23 January 2020, doi: 10. 1016/j.cub.2019.12.013.
Iridescence is the bright, variable colour created by light being refracted in surface structures, e.g. peacock feathers and some butterfly wings. It produces bright clear colours, so most evolutionary biologists claim it evolved to attract mates. However, there is also an older theory that iridescence serves as a type of camouflage, i.e. a means of avoiding predators. Scientists at the University of Bristol set out to test this theory using the wing cases of a brilliant turquoise coloured jewel beetle.
The researchers filled beetle wing cases with mealworms and placed them on leaves amongst vegetation in a British nature reserve. In the same places, they also placed beetle wing cases painted in dull colours, but also filled with worms, and observed how many of those wing cases were picked up by birds. They found iridescent cases were more than twice as likely to left alone by birds foraging in the vegetation.
As birds are considered to be “visual predators”, i.e. they hunt using sight, the scientists concluded that iridescent cases were harder to see. To test this theory they recruited people to look for the beetle cases. Karin Kjernsmo, an evolutionary and behavioural ecologist at the University of Bristol, who led the study, explained, “you never know whether they (birds) can’t see a prey item or if they see it but choose to ignore it. With human participants, you know exactly where the effects lie.” The human searchers found only 17 per cent of the iridescent specimens, but almost 80 per cent of the dull coloured varieties.
Karin Kjernsmo commented: “Our study is the first solid evidence for the idea that iridescence can work as highly-effective form of camouflage, and ultimately this could explain why iridescence has evolved in so many different species of animals.”
Editorial Comment: This study may confirm that iridescence can act as camouflage, but does nothing to explain how such iridescent surfaces got here. Any claim that the shiny colourful beetles survive ‘best’ must accept that they already have iridescent surfaces. It does not tell you why they have them, or when or how they got them.
Experiments such as those described above do confirm that natural selection or “survival of the fittest” is a real phenomenon, but it is not evolution. To enable a dull coloured beetle to change into an iridescent beetle the genes that control its surface structure must be changed, and being exposed to insect-eating birds them will not do this.
In fact, this experiment confirms Biblical biology, i.e. living things were created for the original very good world, but some of their built-in features have enabled them to survive in the fallen world. Iridescence was created for communication and mate attraction, and also because God delights in beauty. In the original good world birds ate only plants, and not beetles, whatever their colour. After the environment degenerated and animals began preying on one another, some creatures survived because their surface colours enabled them to avoid being eaten. This is natural selection at work, but it is not evolution.
News vol. 20, No. 2
12 February 2020
Creation Research Australia