Déroulement des gamétogenèses chez les CrabesCarcinus maenas(L.) etC. mediterraneusCzerniavsky parasités par la Sacculine

Publisher Website
Google Scholar
Abstract
A histological study of the gonads and androgenic glands of Carcinus parasitized with Sacculina carcini showed no correlation between the degree of infestation of the gonads by the roots of the parasite and the progressive inhibition of the course of male and female gametogeneses. Also, no correlation could be observed between the degree of degeneration of the androgenic glands and that of the testes. Modifications in parasitized crab testes essentially involve a degeneration of the mesoderm tissue of the germinative zone; primary gonia become pycnotic after an abnormal development; germ cells already engaged in spermatogenesis become blocked in prophase of meiosis; and ultimately, the testis becomes empty. Progressive degeneration of the androgenic glands, after an initial hypertrophy that starts as early as the internal Sacculina stage, seems related to the disorganization of the neurosecretory centers of the host. Arrest of spermatogenesis at a more or less advanced stage is probably the result of an imbalance in neurohormonal controls acting directly on the germinative zone or indirectly via the androgenic glands. At the level of the ovaries, parasitic infestation leads to inhibition of the second phase of vitellogenesis possibly due to an abnormality in the organization of the vitellogenic follicles. Hormonal imbalances related to the presence of the parasite appear to be responsible for these phenomena.