The spatial distribution of the gregarine Cephaloidophora pacifica Avdeev (Order Eugregarinida) within the digestive tract of Antarctic krill Euphausia superba was examined using samples collected from the vicinity of the Antarctic Peninsula, in order to evaluate their strategy for maintaining their population. Eugregarines were observed to accumulate in the front section of the gut at any host maturity stage. The results of statistical analysis showed that eugregarines at immediately pre-molt stage of the krill decreased significantly in the posterior of the hind-gut, and increased in the anterior of the hind-gut. Thus, the krill's molt stage may be one factor affecting the spatial distribution of eugregarines. As a strategy for avoiding discharge to the outer environment by molting, eugregarines may move to a safety zone (mid-gut). References: 32
展开▼
