Endangered limpets change sex to improve their chances of survival

Nov 13, 2013
Ribbed limpet during sexing process. This was a female, as suggested by the reddish colour at the bottom of the syringe. Credit: Iván Acevedo

The Ribbed Mediterranean Limpet is one of the most endangered invertebrates of the Mediterranean Sea and is classed as being in danger of extinction. Researchers at the Spanish National Museum of Natural Sciences have discovered their reproductive strategy, consisting in changing sex from male to female and vice versa, which improves their ability to adapt to changes in their environment.

The Ribbed Mediterranean Limpet, Patella ferruginea, shares the unfortunate privilege of being included in the Spanish Catalogue of Endangered Species, together with other better known species such as the Iberian Lynx and the Imperial Eagle, under the maximum protection category, 'in danger of extinction'.

This is why a National Strategy was formed in 2008 for this invertebrate, commonly known as the ribbed limpet, for the conservation of the species. Fines for fishing for shellfish with this limpet range between 60,000 and 300,000 euros.

"One of the problems involved in the recovery of the Patella ferruginea is the lack of knowledge regarding basic aspects of its biology. This is the first time we have encountered this part of its on an experimental basis", Javier Guallart, main author of the project and researcher at the Spanish National Museum of Natural Science, told SINC.

The lack of biological knowledge surrounding the species is not unusual, given that the species is so endangered that there are only a few natural colonies left good enough to carry out the research projects. One of the most important colonies of the whole area in which they are located is the Spanish archipelago of the Chafarinas Islands opposite the coast of North Africa..

A team led by Guallart has spent six years travelling to this area to conduct research to explore one of the most essential aspects of the species' biology; its method of reproduction.

"Sexing" limpets is a complicated task

According to the scientist, the ribbed limpet had until now been believed to be a protandric hermaphrodite species. "As a reproductive strategy, this term means that youngsters, when they reach sexual maturity, do so as males and then, at some point during their vital cycle, change sex and become females".

This occurs often in molluscs and, in particular, in limpets. However, this conclusion has normally been based on indirect information. "For example, it is based on the fact that smaller specimens tend to be male and larger ones tend to be female", adds Guallart.

In order to confirm that they really do , in 2006 a complex task began, involving sexing a number of specimens and returning to do it again a year later, during the next reproductive period (this species only reproduces once a year), to check whether they had changed sex.

"This may seem simple, but it is not. Sexing specimens means separating them from the substratum during the time of the year in which they are mature, between October and November, handling them and performing a small biopsy with a syringe to take a small sample of gonad in order to establish the sex according to the sample extracted (oocytes or sperm)", outlines the author.

The specimens were then returned to the coast, in the same place they were captured and this was done so they could adhere to the substratum, enabling them to continue with their way of life.

Also, given that it is a highly protected species, the death rate related to this handling operation had to be minimised which, as outlined in the article, has been achieved by following a protocol that was designed and tested for this purpose.

Females also change sex

In 2007 we discovered that a specimen previously sexed as male in 2006 was now a female, which meant this was the first direct and unprecedented proof of a sex change in the Patella ferruginea.

The work carried out between 2007 and 2008 also brought about further developments. On the one hand, it was confirmed that a number of specimens previously sexed as male were now females and a new unusual development was unearthed: a female had become a male between consecutive reproductive periods.

"The results obtained were fascinating. This reverse sex change from female to male was something anecdotally described for a species of limpet. During subsequent periods, between 2010 and 2011, we discovered that this was not an isolated case; a whole new approach to the method of reproduction of this protected species, which helps it to survive", stated the scientist. When and why the occurs in each case is yet to be explained.

Knowing the main biological parameters of endangered such as this one is vital in order to implement any strategy aimed at their conservation and recovery. "There is still a long way to go", reiterated Guallart.

Explore further: New molecular target for malaria control identified

More information: Javier Guallart, Marta Calvo, Iván Acevedo y José Templado (2013) "Two-way sex change in the endangered limpet Patella ferruginea (Mollusca, Gastropoda)" Invertebrate Reproduction & Development, 57(3): 247-253. dx.doi.org/10.1080/07924259.2012.754794

add to favorites email to friend print save as pdf

Related Stories

New molecular target for malaria control identified

Oct 29, 2013

A new study led by Harvard School of Public Health (HSPH) and University of Perugia (UNIPG) researchers has shown that egg development in the mosquito species primarily responsible for spreading malaria depends ...

Guppies lie about mate choice to trick rivals

Sep 09, 2013

When it comes to sex among guppies, competition is high for those at the top of the game. To get around this predicament, a recent study has shown, guppies use trickery. ...

Pantry pests trade immunity for sex

Jun 07, 2013

(Phys.org) —When presented with a bevy of beauties, male meal moths - the scourge of many a household pantry - will prefer to invest in sex over self-preservation, according to researchers.

Lovelorn frogs bag closest crooner

May 20, 2013

What lures a lady frog to her lover? Good looks, the sound of his voice, the size of his pad or none of the above? After weighing up their options, female strawberry poison frogs (Oophaga pumilio) bag th ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

Apr 18, 2014

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...