They are neither white nor gold, nor black and blue. But in an optical puzzle similar to the dress, the colorful snails make scientists at Nottingham University turn to technology to decide whether the shells of some snails are pink or brown.
The beautiful one Cepaea nemoralis – commonly known as plant snails – are found throughout Europe in different colors, from yellow to pink to brown, and some also have engraving patterns.
But new research published in the academic journal heredity, shows that differences in the way people see and categorize colors often make it difficult to be sure about the color of snails' shells, which leads to heated debate among scholars.
The problem of how to classify colors has important implications for studying the evolution of the snail's snail's color in response to factors including climate warming and hide from predators.
Dr. Anugius Davison, an associate professor and reader on evolutionary genetics at the University Life Sciences School, said: "Templates and shell color are extremely variable – almost as a fingerprint. From our research and subsequent interpretation, it is important to have a reproducible color measure. "
"The problem is that there are obvious differences in the way people perceive and categorize their color, making it very difficult to compare the different species."
In the past century, the study of animal color is crucial to help us understand the principles of biology, especially in terms of genetics and evolution. Surveys on color distribution and impact on the way predators can identify their prey have shaped our understanding of how natural and sexual selection work in wild populations and the impact of climate change.
These snails, which are the second most common snail in the UK and are often found in gardens and hedges, are also used in an Evolution Megalab experiment in which civil scientists collect snails and record color. Scientists compare the color over time – there is a clear indication that the proportions of the different types of envelopes are changing. But these civilian scientists are facing the same problem in classifying colors.
Earlier studies of snails show that they can be sorted into three color groups – yellow, brown and pink.
It may be reasonable to assume that the yellow snails are in dry, dry grasses where they can effectively blend in the background, while their brown colleagues can adhere to the darker forest environments to conceal them. Snails use their color to avoid predators – ie. such as camouflage – and avoid overheating in an open environment.
But studies of snails show that it's not always that simple – different colorful snails are in different environments.
Color can also play a role in the way predators, especially birds, like the songs of the song, choose their prey. Birds develop a preference for the most common color of the snail over time, so rare species avoids predation.
To enable scientists to study the exact nuances of these issues, they need a way to sort them accurately into color groups.
In the Nottingham study, rose snails from the UK and continental Europe were categorized by Dr. Davison and PhD student Hannah Jackson from the eyes.
The same snails were then analyzed using a spectrometer, a machine that directs light to the snails and measures the spectrum of light reflected from the shells.
Using these methods, scientists have been able to harvest the snails in brown, pink and yellow groups and this compares to how scientists have categorized the same snails with the naked eye.
The results show that humans are largely capable of categorizing yellow snails, but have been less successful in identifying snails that are brown or pink. They also did not agree with each other that they were pink and brown.
The work provides scientists with an initial measure of further research into the color of the animals and the genes underlying these variations.