INFESTATION BY OCTOLASMIS BULLATA (AURIVILLIUS, 1894) (CIRRIPEDIA, THORACICA) OF PORTUNUS SANGUINOLENTUS (HERBST, 1783) (BRACHYURA, PORTUNIDAE), AND POSSIBLE INTERACTIONS WITH DIPLOTHYLACUS SINENSIS (KEPPEN, 1877) (CIRRIPEDIA, RHIZOCEPHALA)

摘要

Specimens of the commercially important crab Portunus sanguinolentus (Herbst, 1783) were collected monthly in Honghai Bay, P.R. China and examined for the presence of two barnacles: the Lepadomorpha Octolasmis bullata (Aurivillius, 1894) and the Rhizocephala Diplothylacus sinensis (Keppen, 1877). O. bullata was observed in the branchial chambers and prevalence of their infestation varied in the monthly collections. High prevalence occurred in the time from June to August and from October to February. The mean intensity of O. bullata was 23.33 +/- 18.91 barnacles per infested host, showing higher intensity in larger crabs. The parasite D. sinensis was observed on host surfaces with externae or scars, and their prevalence was high in winter and low in summer. Crabs parasitized by D. sinensis showed a heavier fouling by O. bullata than the non-parasitized crabs. Larger crabs were more vulnerable to the infestation of O. bullata and the parasitism of D. sinensis. Thus, interaction of O. bullata and D. sinensis may cause synergistic effects on the host's health. Due to the great economic importance of the crab, attention should be paid to this relationship.