中文摘要：

模糊秀体潘是热带水体中枝角类的主要优势种，它在竞争及对热带水体的适应方面的优势尚不清楚。本文以模糊秀体潘为研究对象，观察不同食物浓度下其生长和繁殖的特点，探讨模糊秀体潘成热带水体优势种的原因。以蛋白核小球藻为食物，浓度梯度设为0.05mg／L、0.1mg／L、0.3mg／L、0.6mg／L和1.0mg／L小球藻浓度为0.05mg／L的培养液中，模糊秀体潘存活率很低且未观察到繁殖现象其它4个浓度小球藻喂养的模糊秀体潘体长生长率和最大体长均随食物浓度的升高而增加，最大体长分别达到1.087mm、1.125mm、1.225mm、1.313mm；食物浓度对模糊秀体溢的胚胎发育时间，平均寿命，个体累计产幼数无显著影响：随着食物浓度的升高，模糊秀体滏初次怀卵体长显著增加，繁殖前期的历时相应缩短，平均每胎产幼数增加：内禀增长率随食物浓度升高而增大，达到0.6mg／L后比较稳定。浓度为0.6mg／L时，模糊秀体潘的净生殖率也达到最大值。1.0mg／L组的世代时间最短，内禀增长率接近最大值。0.6mg／L和1.0mg／L为模糊秀体潘生长比较适宜的食物浓度。热带自然水体中，模糊秀体潘相对其它浮游动物个体小和怀卵率低的现象并非食物不足所致；食物充足条件下的最大成体的个体大小与野外样品接近，也说明自然水体中捕食并没有显著影响成体的个体大小。模糊秀体潘体型较小、身体透明、行动敏捷，容易逃避鱼类的捕食，可能是模糊秀体潘能在食物丰富的热带水体中，特别是透明度较低的富营养化湖泊中能够成为枝角类中优势种的主要原因。

英文摘要：

Diaphanosoma dubia is one of the dominant species in most tropical reservoirs, however, how it becomes dominant and whether food concentration plays a key role are unclear. In order to study the effects of algal food concentration on the growth and reproduction of D. dubia and to understand the possible causes for this small animal to be one of the dominant species in the tropical water bodies, the animals were fed by Chlorella pyrenoidosa as food with five organic carbon concentrations： 0.05mg/L, 0.1mg/L, 0.3mg/L, 0.6mg/L and 1.0mg/L, respectively. The survival rate was quite low and no reproduction at the food concentration of 0.05mg/L. The somatic growth rate and longest body length increased with the organic carbon concentrations of Chlorella pyrenoidosa, the longest body length was 1.087mm, 1.125mm, 1.225mm and 1.313mm, respectively. Food concentration showed no significant effect on embryonic and juvenile development periods, lifespan and the number of the cumulative eggs for each adult. The size at maturity and the mean number of eggs per brood both increased with the increasing organic carbon concentrations of Chlorella pyrenoidosa, but the duration of reproduction decreased. The intrinsic rate of increase increased with the increasing organic carbon concentrations of Chlorella pyrenoidosa. The net reproduction rate and the intrinsic rate of increase showed peak values at the food concentration of 0.6mg/L. Under the maximal food concentration of 1.0mg/L, the generation time was shortest and the intrinsic rate of increase was closed to the peak value. The proper concentrations for the growth ofD. dubia were 0.6mg/L and l.Omg/L The D. dubia is smaller than many species in cladocerans such as Daphnia galeata and has lower number of eggs per female. Its small body size and few eggs seems not be caused by low food concentration. The maximal sized animals cultured in the high food concentration is close to the animals found in natural water bodies, this means that predation doesn＇t significantly reduce its