Studies of the Biology of Some Nippotaenid Cestodes

Abstract

The cyclopoid copepod Macrocyclops albidus is an intermediate host of the nippotaenid cestodes Christaenia fragilis and Christaenia decidua in lake Taupo. It can also act as intermediate host to Christaenia contorta, from the Waikenae area. The life cycle requires only two hosts. All three species develop a cercomer during ontogeny in M. albidus, and six embryonic hooks are never retained on the cercomer. An infective metacestode takes about 30 days to develop at 18 ºC. Known hots fed metacestodes retained them, and C. decidua eggs infective to copepods were recovered from experimentally infected Gobiomorphus cotidianus. Bullies and smelt from the Kuratau rivermouth had au overall prevalence of 46.6 % and 25.4 % respectively with nippotaenid cestode. Both prevalence and intensity of infection varied for both species over the year studied monthly at the Kuratau rivermouth. Prevalence of C. fragilis peaked in spring, and intensity in late summer. Prevalence and intensity of C. decidua in G. cotidianus peaked in spring. The taxonomy of the order Nippotaeniidea Yamaguti 1939 has been revised using type, and other material and a new genus erected to accommodate species which do not exhibit a ring of circular muscles at the anterior rim of their apical sucker. A new species of Nippotaeia has been described, the first record of nippotaenid cestodes from Australia.