5 days ago
Fight to save ‘most beautiful snail' from most voracious predator — us
No one knows why the Polymita snails of Cuba are so beautiful, or why their beauty is so varied. Probably, though, the array of different colours and stripes evolved as a way of avoiding predators.
Which is why it is so ironic that those adornments are — today — the reason it is attracting the most voracious predator of all: us.
Conservationists have warned the shells of this disappearing species are being sold to collectors, who may not even realise the snails are endangered.
Now a global collaboration of scientists is looking to better understand and breed in captivity these magnificent molluscs — with the hope of preserving them.
'They are so beautiful and extraordinarily variable,' said Professor Angus Davison, from the University of Nottingham. This means that as a snail scientist he finds himself in an unusual situation. 'While all snails are interesting and beautiful to me, most snails, by and large, are not outwardly beautiful to other people.'
He has been part of a team collecting samples in Cuba, with a view to mapping their DNA. He is interested in how many species there are and how they are related. It is believed that there are six, but traditional methods of counting rely heavily on intricate analysis of their genitals. The hope is that genetic data could both be more definitive, and also provide clues not contained in their penises to explain why they are like this at all.
Paradoxically, said Davison, being colourful can be a way of evading predation — and this is his leading hypothesis. 'You might assume they stand out against the background. That's not necessarily true, depending on where they live.' But being very different from each other, in the way they are, could be a positive survival strategy.
'Most likely there's a bird out there that eats the snails. That bird gets a search image in its head for the most common snail — let's say it's a yellow snail. And then you get a gene change that makes a green snail. The green snail will not be eaten because the bird doesn't see them. And so the green snails will become more common.
'And then another mutation arises, which makes an orange snail. And so on.'
Until, eventually, there are enough different colours that while they evade birds, they catch the eyes of tourists instead.
It is illegal to collect and sell the snails, but it is hard to enforce. 'The problem is, Cuba's undergoing very great financial hardships. So there's a very great incentive for locals to collect the shells and sell them.'
Davison's worry is that publicising the beauty of the snails might increase the market. His hope, though, is that educating people about them could decrease it.
'No person in the UK would buy rhino horn if offered it on a holiday. But there are people who will happily buy a shell, not even thinking about the animal or where it came from.'
