不同浓度的牟氏角毛藻对双齿许水蚤生长、存活和生殖的影响

Effects of food concentration on the development, survival, reproduction of calanoid copepod(Pseudodiaptomus dubia)

为研究不同浓度的牟氏角毛藻对双齿许水蚤生长、存活和生殖的影响,并构建双齿许水蚤在不同食物浓度下的种群生命表。实验共设5个浓度组(0.5×10~5、3×10~5、6×10~5、12×10~5、17×10~5个/m L),结果显示,食物浓度对双齿许水蚤的幼体生长率、发育时间、存活率及孵化率有显著的影响。当食物浓度为3×10~5~6×10~5个/m L时,双齿许水蚤的发育速率、生长率及孵化率显著高于浓度最低组(0.5×10~5个/m L)和浓度最高组(17×10~5个/m L),其幼体的发育时间为174~192 h,生长率为0.6~0.64μg C/d,孵化率为464.2~608.2个/雌。存活率则随着食物浓度的升高而降低,浓度较低的0.5×10~5、3×10~5、6×10~5个/m L组的存活率均达80%,显著高于12×10~5及17×10~5个/m L组。食物浓度越高,生命周期越短。当食物浓度为3×10~5及6×10~5个/m L时,桡足类的内禀增长率均达0.237/d,比最低浓度组(0.5×10~5个/m L)及最高浓度组(17×10~5个/m L)高出28%~32%。研究表明,食物浓度过高或过低均不利于双齿许水蚤的种群增长,其生长繁殖的最适食物浓度范围为3×10~5~6×10~5个/m L。

An experiment was carried out to evaluate effects of food concentration on the development, survival,reproduction of a calanoid copepod（Pseudodiaptomus dubia）, in which the population life table was formed at different food concentration. The animals were fed with Chaetoceros muelleri as food designated with five food concentrations, 0.5×10^5, 3×10^5, 6×10^5, 12×10^5 and 17×10^5 cells/m L, respectively. The results showed that different concentrations of C. muelleri had significant effects on the development, survival and reproduction of P. dubia.When the food concentration was 3×10^5 – 6×10^5 cells/m L, the development time, growth rate and hatching rate of P. dubia was 174–192 h, 0.6–0.64 μg C/d, and 464.2–608.2 neonates per female, respectively, which were significantly higher than those of the lowest concentration（0.5×10^5 cells/m L） and the highest concentration（17×10^5 cells/m L）. The survival and lifespan decreased with the increase of food concentration. The survival of P.dubia reached up to 80% when the food concentration ranged from 0.5×10^5 cells/m L to 6×10^5 cells/m L, which were significantly higher than that of the 12×10^5 and 17×10^5 cells/m L. When the food concentration was 3×10^5 – 6×10^5 cells/m L, the intrinsic growth rate of P. dubia was 0.237/d and 28%–32% higher than that of 0.5×10^5 and17×10^5 cells/m L. Therefore, putting too much or too little food would be disadvantageous to the population growth of P. dubia. Therefore, the most favourable food concentration for P. dubia would range from 3×10^5 to 6×10^5 cells/m L.