Infestation by Carcinonemertes divae (Nemertea: Carcinonemertidae) in Libinia spinosa (Decapoda: Pisidae) from São Sebastião Island, SP, Brazil

Abstract

Nemerteans of the genus Carcinonemertes are obligate symbiotic egg predators of many decapod crustaceans. This study presents the prevalence and intensity of infestation by Carcinonemertes divae in the crab, Libinia spinosa, from São Sebastião Island, São Paulo State, Brazil. Overall prevalence of infestation was 69.2% and mean intensity of infestation was 20.8±3.4 (range: 1–148). Significant differences in prevalence and mean intensity of infestation were observed between males and females and between ovigerous and non‐ovigerous adult females of Libinia spinosa. Prevalence and mean intensity of infestation did not differ significantly between juvenile and adult crabs or among ovigerous crabs with eggs in different stages of embryogenesis. Carapace width of male crabs was negatively correlated with prevalence of infestation by Carcinonemertes divae. Sexual contact appeared to be a source of transmission of worms between males and females of Libinia spinosa.

Keywords:

• Infestation
• symbionts
• Carcinonemertes divae
• Libinia spinosa
• Brazil

Acknowledgements

The authors would like to express their gratitude to the “Programa de Pós‐Graduação”, area Zoology, of the Instituto de Biociências, Universidade de São Paulo, and the Centro de Biologia Marinha, Universidade de São Paulo, for providing logistic and laboratory facilities. We would like to thank Elso Alves da Silva for his assistance in the field. We are grateful to the staff of the Smithsonian Marine Station at Fort Pierce, Florida, for providing logistic facilities while one of the authors (CS) was doing the statistical analyses and finishing the manuscript. We thank two reviewers for helpful comments that improved this manuscript. Finally we would like to thank FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) for providing a scholarship grant (process number 01/01797‐2) to CS.