Patterns of sexual reproduction among parasitic platyhelminths
Patterns of sexual reproduction among parasitic platyhelminths
复制标题
寄生扁形动物的有性生殖模式
作者：
P. Nollen
总结以往的研究，精子发生和卵子发生的二殖吸虫，单殖吸虫和绦虫进行了审查，包括同位素标记技术已被用来确定时间的精子发育阶段。类似的标记实验也提供了关于卵母细胞在雌性生殖道中的发育和运动的信息，以及指示卵黄腺中细胞分裂和发育的模式。有关寄生性扁形动物的繁殖行为的文献被认为是从一些观点，包括模式的交叉和自我授精发生在雌雄同体的双殖吸虫，雌雄异株的交配行为，精荚生产和单殖吸虫之间的授精和繁殖行为的多生绦虫。寄生性扁形动物之间的自交的影响被认为是可能的遗传有害后果。此外，考虑到一些物种需要交叉授精或至少存在另一种蠕虫才能正常生长和性发育的机制。最后，实验研究进行了审查，揭示了对杂交的障碍之间存在明确的物种寄生扁形动物的强度。
SUMMARY Previous studies on the spermatogenesis and oogenesis of digeneans, monogeneans and cestodes are reviewed, including those in which isotopic labelling techniques have been utilized in order to determine the temporal duration of spermatogenic development stages. Similar labelling experiments have also provided information on the development and movement of oocytes in the female reproductive tract as well as indicating patterns of cell division and development in vitelline glands. The literature relating to the inseminative behaviour of parasitic platyhelminths is considered from a number of viewpoints including the patterns of cross-and self-insemination that occur in hermaphroditic digeneans, the mating behaviour of dioecious schistosomes, spermatophore production and insemination among monogeneans and the inseminative behaviour of polyzoic cestodes. The implications of selfing among parasitic platyhelminths are considered with respect to possible genetically deleterious consequences. In addition, consideration is given to the mechanisms underlying the fact that some species require cross-insemination or at least the presence of another worm in order to undergo normal growth and sexual development. Finally, experimental studies are reviewed which shed light on the strength of the barriers against hybridization that exist between well-defined species of parasitic platyhelminths.