Smi Nico J, Basson Linda, Van As Jo G
School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK.
Folia Parasitol (Praha). 2003 Jun;50(2):135-42. doi: 10.14411/fp.2003.024.
Laboratory work was conducted to elucidate the life cycle of the South African gnathiid isopod, Gnathia africana Barnard, 1914. The natural fish hosts of this temporary parasite, the super klipfish Clinus superciliosus (Linnaeus, 1758), were exposed to gnathiid larvae in the laboratory. It was found that G. africana has three larval stages, consisting of three unfed (zuphea) and three fed (praniza) stages. First-, second- and third-stage zuphea larvae took an average of 2 h 18 min, 2 h 43 min and 10 h 8 min respectively to complete their feeding and the first- and second-stage praniza moulted at 8 and 10 days respectively into the next zuphea stage. Three to six days after its last blood meal, the sex of the third and final praniza stage could be determined by the presence of either a testis or two ovaries in the dorsal pereon. Male larvae moulted into adult males between 8 and 10 days post feeding. Female larvae moulted at approximately 17 days into adult females. Fertilisation of the eggs by the male took place within 24 hours of completion of the female moult. The development of the embryos and subsequent release of the young larvae between 15 and 23 days post fertilisation completed the cycle. This entire cycle took approximately 62 days in water temperatures of 20-25 degrees C.
开展了实验室研究以阐明南非颚虱等足类动物（Gnathia africana Barnard，1914）的生命周期。在实验室中，将这种临时寄生虫的天然鱼类宿主——超级鳚（Clinus superciliosus，林奈，1758）暴露于颚虱幼虫。研究发现，非洲颚虱有三个幼虫阶段，包括三个未进食阶段（蚤状幼虫）和三个进食阶段（前幼体）。第一、第二和第三阶段的蚤状幼虫完成进食平均分别需要2小时18分钟、2小时43分钟和10小时8分钟，第一和第二阶段的前幼体分别在8天和10天后蜕皮进入下一阶段的蚤状幼虫。在最后一次吸血后三到六天，可以通过背甲中是否存在睾丸或两个卵巢来确定第三也是最后一个前幼体阶段的性别。雄性幼虫在进食后8至10天蜕变为成年雄性。雌性幼虫大约在17天蜕变为成年雌性。雄性在雌性蜕皮完成后24小时内使卵受精。受精后15至23天胚胎发育并随后释放幼体，至此完成整个生命周期。在水温20至25摄氏度的条件下，整个周期大约需要62天。
