Larger snails change their sex into females

According to a new research it seems that snails change their sex when they touch one another. It has been known for long that some animals, such as gobies, moray eels, wrasses and clownish have the ability of changing their sex. Now, the slipper snail gets into the category of sex-changing animals.

Studying the tropical slipper limpet, also known as slipper snail, researchers discovered that when two male snails stay together it is enough for them to be touching each other and one of them transforms into a female. Usually it is easier and faster for larger snails to become females than it is for smaller ones.

Rachael Collin of the Smithsonian Tropical Research Institute and co-author of the study declared that she was ‘blown away’ by the result of the study. She claims that she would expect snails to use chemicals release to change their sex rather than simple touch.

On their scientific name Crepidula cf marginalis, the tropical slipper limpets live in areas along the shore hidden under rocks. They feed by filtering plankton from the water. The snails have flattened and thin shells with a built-in shelf. They usually live in clusters but they can also be found alone or in groups of two or three individuals consisting typically of a large female with one or two males riding on the back of her shell.

Male limpets have enormous penis which can reach the size of their whole body. This huge length is needed in order for them to be able to get around and under the shell of the female so they can reach her genital opening.

Since producing eggs requires much more energy than producing sperm, usually the bigger individual is the one who changes their sex. When their sex is changing the penis is shrinking at the same time as female genitalia are developing.

In order to analyze these changes the scientists used more pairs of male snails kept in recipients with seawater. Some of the pairs were allowed contact while others were separated by a mesh barrier that didn’t allow touch but water could pass through. Scientists wanted to see if the snails use chemicals in water to trigger the sex change.

However, the results showed that those snails which were allowed to touch grew much faster and one of them changed into female in a much shorter time than the pairs which were kept apart. In conclusion, snails change their sex when they touch.

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