The reproductive cycle of the entocommensal nemertean Malacobdella arrokeana

S. VALERIA TESO; GREGORIO BIGATTI; M. CIELO BAZTERRICA; NESTOR F. CIOCCO; PABLO E. PENCHASZADEH

INVERTEBRATE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2006 vol. 125 p. 314 - 324

1077-8306

The reproductive cycle of the entocommensal nemertean Malacobdella arrokeanainhabiting Panopea abbreviata from San Jose´ Gulf, Patagonia, Argentina, and the nemertean–host relationship were investigated. The mature nemertean population showed a sexratio of 1:0.64, with females predominating. The number of individuals of M. arrokeanaper host varied from 1–60 individuals (mean7SD53.779.4mm). Different stages ofgonadic development were observed in individual nemerteans. Spawning peaks occurredduring late summer and early spring. Sexually mature individuals of both sexes were presentyear round, possibly indicative of a continuous breeding period. Our results suggest that M.arrokeana has no cannibalistic habits and confirm its entocommensal symbiosis with P. abbreviata.