DAO 59:151-158 (2004)  -  doi:10.3354/dao059151

Parasitic castration of Eurhomalea lenticularis (Bivalvia: Veneridae) by a digenetic trematode: quantitative histological analysis

Katherinne Valderrama1, Marcelo Oliva2, Bernardita Campos3, Donald Brown1,*

1Departamento de Biología, Instituto de Ciencias Biológicas y Químicas, Facultad de Ciencias, Universidad de Valparaíso, Casilla 5030, Valparaíso, Chile
2Facultad de Recursos de Mar, Universidad de Antofagasta, Casilla 171, Antofagasta, Chile
3Facultad de Ciencias del Mar, Universidad de Valparaíso, Casilla 5080-Reñaca, Viña del Mar, Chile
*Corresponding author. E-mail:

ABSTRACT: The clam Eurhomalea lenticularis may be parasitized by digenean trematodes of the family Plagiorchidae, specifically in the gonads (parasitic castration). A quantitative histological analysis of the parasitized gonads demonstrated a significant decrease in gonadal area, in the size of individual acini, and in the numbers of differentiated germ cells compared to unparasitized clams. Castration may be caused by mechanical compression due to trematode sporocyst growth. However, the uniform loss of germ cells in areas without sporocysts suggests that a more generalized mechanism is responsible. We suggest that parasitic castration has a primary effect on the host's neuroendocrine and gametogenic systems that regulate gamete production.

KEY WORDS: Bivalve mollusc · Parasitic castration · Histological analysis · Eurhomalea lenticularis · Digenea · Trematode · Central Chile

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