限食对合浦珠母贝幼虫生长、成活及变态的影响

Effects of food restriction on growth, survival and metamorphosis of Pinctada fucata

  • 摘要: 自2009年4月27日至2009年5月25日,在不同投饵条件下研究了限食对合浦珠母贝(Pinctada fucata)幼虫生长、成活和变态的影响。结果显示,试验初期对照组幼虫的壳长、壳高日增长率逐渐升高,自第20天开始迅速下降;试验一组(隔天投喂)和二组(隔2 d投喂)幼虫的壳长、壳高日增长率缓慢升高,且与对照组同期幼虫的日增长率差异显著,这表明饵料是否充足直接影响马氏珠母贝幼虫的生长。试验期间,对照组幼虫的成活率逐渐降低,畸形率无显著性变化,而试验一组和二组幼虫的成活率显著低于对照组,试验二组幼虫的畸形率高于同期对照组和试验一组幼虫的畸形率,表明在食物匮乏的情况下,幼虫的发育受到影响。对照组幼虫在第20天时开始变态,随后变态率逐渐升高,试验一组幼虫在第30天时开始变态,而试验二组幼虫在试验期间一直没有变态,表明该组幼虫的营养状况不足以支持其变态附着。

     

    Abstract: In the present study, the effects of food restriction on the growth, survival and metamorphosis of Pinctada fucata were investigated from April 27 to May 25 in 2009 under different feeding conditions. The results showed that the daily growth rate of shell length and shell height in the control group increased gradually but decreased suddenly from day 20, while those in group 1 (feed every other day) and group 2 (feed every 3 days) increased slowly, which significantly differentiated with the case in the control group. It indicated that whether the food was sufficient influenced the growth of P.fucata directly. In the experiment, the survival rate in the control group decreased but the deformity rate of larvae showed no significant difference; the survival rate in group 1 and group 2 were significantly lower than that in the control group, and the deformity rate in group 2 was significantly higher than that in the control group, which indicated that the growth of the larvae was influenced byfood shortage. The larvae in the control group metamorphosed at day 20, and the metamorphosis rate increased gradually. The larvae in group 1 metamorphosed at day 30, but thosein group 2 did not metamorphose throughout the experiment, which showed that the larvae did not have enough nutrition for metamorphosis.

     

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