食物密度波动对蒙古裸腹溞种群密度和雄体比率的影响

Effects of Food Density Fluctuations on Population Density and Male Ratio of Moina mongolia Daday

在相对恒定的盐度（22）、温度（24～28℃）和自然光照下,培养液为密度（3～4）×106 cells/mL小球藻藻液,培养液更换方式1次/12 h、1次/6h和机动更换3种方式,初始种群密度为0.02 ind/mL,研究不同食物密度波动,对蒙古裸腹溞的种群密度变化规律和雄体比率的影响.结果表明,在29 d的培养期限内,种群密度呈现出典型的“S”型曲线,明显分为4个阶段：缓慢增长期、快速增长期、稳定期、下降期,固定组1次/12 h的种群密度明显低于固定组1次/6h和机动组,种群密度最大时可达到47 000 ind/L;雄体百分率表现为固定组1次/12 h＞固定组1次/6 h＞机动组,且3个组别均出现了2次雄体产出高峰期,最大雄体百分率可达到21.3％,分析得出蒙古裸腹溞雄体的产出与食物密度波动和种群密度有密切的关系,但是在较高的种群密度下并不能诱导出非常高的雄体百分率.

This paper studied the effects of food density fluctuations on population density and male ratio of Moina mongolia Daday. The experiment was studied under constant relative condition of salinity（22）, temper- ature（24-28 ℃）, natural light, and the algae（Chlorella sp.） replace density was 3 to 4×10^6 cells/mL. The results showed that population density showed typical ＂S＂ curve, which was divided into 4 phases： the period of slow growth, rapid growth period, stable period, declining period. The population density of 1 times/12 h was lower than 1 times/6 h and mobile group. The maximum population density can reach 47 000 ind/L, and the three groups had two peak of male output. The largest percentage of male can reach 21.3%. The result of analysis showed that there was a close relationship between food density fluctuation and population density for M.mongolia Daday male output. But when the population density was very high, it can not be induced very high percentage of males.