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Shell shock: a biologist’s quest to save the endangered painted snail

Bernardo Reyes-Tur studies painted snails housed in plastic bottles and containers in his breeding lab in Santiago de Cuba, Cuba

Bernardo Reyes-Tur is a professor of conservation biology at University Oriente in Santiago de Cuba, Cuba. Credit: Bruno D’Amicis

In my laboratory at the University of Oriente, in Santiago de Cuba, we study the six species of Polymita, known as painted snails, which are endemic to eastern Cuba and are in danger of extinction. The shells’ vibrant swirls and stripes look as if they’ve been painted by hand. Unfortunately, you can find their shells for sale on eBay, and many are exported to places such as the United States, China and Spain for use in art and jewellery — despite laws banning such trade.

Painted snails live in mangrove forests, in sandy and rocky coastal areas and in rainforests. Some species are important parts of agro-ecosystems, such as coffee and coconut plantations. In 1995, my team began a breeding laboratory. We needed a way to isolate individual snails in containers, and to provide them with food, such as a fig-tree branch covered with moss, lichens and sooty mould fungus. But getting enough of the right containers was a problem because the nation was in an economic depression then.

My students realized that when tourists visited Cuba, they left behind plastic one-litre water bottles. Since then we’ve been using them as living spaces for the snails.

We study the breeding behaviour, nesting, hatching and growth of these hermaphrodites. If we want to save Polymita, we need to know more about their reproduction patterns — why one species hatches only between July and December, for instance.

When mating, Polymita use a protrusion called a dart to transfer hormones, but we know very little about it. We are studying how these hormones affect the reproductive tract and influence fertilization success.

In Cuba, there is more support for medical research than for biodiversity research. So we look for collaborations around the world. My motto is a Cuban saying: “We have the ‘no’, and therefore always have to look for the ‘yes’.” In other words, there is always another way, if you keep looking.

Close up of a collection of Cuban tree snail empty shells

Polymita’s vibrant swirls and stripes make the endangered snails valuable for illegal trade.Credit: Bruno D'Amicis/NPL

Nature 594, 606 (2021)



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