Reproductive cycle and parasitism in the clam Anomalocardia brasiliana (Bivalvia: Veneridae)

Abstract

The reproductive cycle and parasitism in the clam Anomalocardia brasiliana were studied in two different areas, an intermediate beach (Cidade) and a tidal flat (Araçá), in Southeast Brazil. Four gametogenic stages were described for males and females in both areas. Mature and spawning individuals were present throughout the period of study at Cidade and Araçá; however, major temporal differences were recorded between sites. Whereas only a few individuals in the resting stage were recorded at Cidade throughout the study period, resting stage individuals were frequent at Araçá. Moreover, a shorter period of gametogenesis was observed at Araçá than at Cidade. Oocyte number was the most effective parameter to differentiate gametogenic stages. An unidentified digenetic trematode was the only parasite infecting A. brasiliana at the study sites, and caused castration of all hosts. Parasite prevalence (proportion of infected hosts) was similar and low (ca 7.5%) at Cidade and Araçá and therefore is not expected to compromise the reproductive output of these populations. Comparison with data from previous studies suggests a latitudinal pattern for the reproductive biology of A. brasiliana, with resting stages occurring only at two high-latitude sites; however, no evidence was found for a latitudinal pattern of trematode prevalence in this species.

Keywords:

• Mollusca
• digenetic trematode
• gametogenic cycle
• parasitic castration
• Veneridae

Acknowledgments

I am grateful to Dr Cecília Amaral for the support to conduct this research and for the guidance that she provided throughout my dissertation. Thanks to Nathalia Padovanni and Hélio H. Chechon for their critical review on the first draft of the manuscript. I also thank Dr Marlene Tiduko Ueta for help with parasite identification, the Centro de Biologia Marinha (CEBIMar/USP) for field support and data provided, and all colleagues and friends, especially Leonardo Yokoyama and Gisele Pelegrini, who helped during the field work. Thanks to Dr Janet W. Reid and Rebecca Fletcher for the English revision of this manuscript. Finally, I wish to express my gratitude to the editor Professor Alan Hodgson and one anonymous referee for their impressive contribution that greatly improved this work.

Additional information

Funding

This study was supported by the Brazilian National Council for Technological and Scientific Development (CNPq Process [grant number 131594/2008-7]) and São Paulo Research Foundation (FAPESP Process [grant number 2008/52392-1]), which provided me a Master’s fellowship and grants.