Two-way sex change in the endangered limpet Patella ferruginea (Mollusca, Gastropoda)

Abstract

Direct observations of sex change were made on the endangered limpet Patella ferruginea in Chafarinas Islands (Alboran Sea) between 2006 and 2011. Individuals of the species were sexed and tagged during spawning season for subsequent monitoring to determine possible sex changes. Mortality was minimized by following a carefully designed sexing protocol. Out of 49 tagged specimens (41–88 mm in size) that could be sexed in successive years (28 males and 21 females), 16 males changed into females between consecutive years (50.0% of males smaller than 70 mm and 100% of males larger than this size), while two females changed sex to males between consecutive spawning seasons (both were smaller than 70 mm). Overall, 36.7% of the limpets monitored changed sex between consecutive years: 57.1% of males became females and 9.5% of females changed to males These observations confirms the occurrence of two-way sex change, or reverse sequential hermaphroditism, in P. ferruginea. Our findings unveil this sexual strategy in this endangered limpet and provide new direction for studies designed to address the mechanisms and factors that determine sex change and its effects on population dynamics.

Keywords:

• reproduction
• hermaphroditism
• Chafarinas Islands
• Alboran Sea

Acknowledgements

The authors thank Patricia Cabezas for her valuable contribution to field work in the Chafarinas Islands and Ana Burton for editorial assistance. This work was funded at its late stage by the project “Action plan for viability proposals of the endangered limpet, Patella ferruginea” (Project 0 of the Spanish Research Council –CSIC- Foundation) and in former stages by grants awarded by the Organismo Autónomo de Parques Nacionales and the Dirección General de Conservación de la Naturaleza of the Spanish Ministerio de Medio Ambiente. We thank these institutions for permission to examine a species protected by Spanish law. We are also indebted to Javier Zapata and the staff of the Biological Station of the Chafarinas islands, the Spanish Ministerio de Defensa and the military personnel on the island for facilities provided during the fieldwork. Lastly, we deeply appreciate the comments and suggestions of the reviewers, which have improved the manuscript considerably.