Advanced development of the cystacanths of Neoechinorhynchus beringianus (Eoacanthocephala: Neoechinorhynchidae) living in intermediate hosts

Abstract

This study of naturally infected ostracods revealed advanced sexual development in cystacanths of N. beringianus and detected signs of maturation of both female and male acanthocephalans in intermediate hosts. In addition, the study observed ultrastructural evidence of the presence of mature spermatozoa in the seminal vesicles of male cystacanths and of the formation of secretory granules in their cement glands. The study provides quantitative data on the occurrence of advanced development of cystacanths in intermediate hosts and of the immaturity of acanthocephalans in definite hosts. Furthermore, the study considers the temperature conditions for larval development of N. beringianus in the natural population and the probable dependence of cystacanths’ maturation rate on these conditions. Finally, the study discusses the biological significance of the phenomenon detected.