太平洋牡蛎幼体的趋性行为

The Taxic Behavior in the Larvae of Crassostrea gigas

测定了太平洋牡蛎(Crassostca gigas)幼体各个主要发育期的趋光性和趋地性。结果表明,担轮幼体表现为负趋地性和负趋光性,而其它几个幼体发育期却转化为正趋地性和正趋光性。牡蛎幼体的趋地反应强度大于趋光反应。幼体对于不同光强的反应水平差异较小,但具有较强的光动性反应,缺乏光探反应,因此,初步认为,自然海区中,牡蛎幼体难以随光强的昼夜变化而垂直移动,其垂直分布是随着发育程度而逐步朝向水体下层的。

The phototaxic and geotaxic responses during the larval develo pment of Crassostrea gigas were investigated under laboratory condition, Trochophore larvae showed negative phototaxic and geotaxic responses but in veliger and veliconcha larvae, they would response positively to light and gravity. By comparison, the geotaxic response was usually stronger than the phototaxic response. Phobic behavior didn't appear in the larvae of C. gigas. In considering the little difference in larvae responsing to various light intensity along with the photokinesis larvae possessed, it was suggested that the larvae could not make vertical migration, with the dinural fluctuation of natural light intensity. The vertical distribution of larvae was shifted downward gradually.