若干生态因子对蒙古裸腹溞生殖方式转变效应的实验

实验室中，以不同种群密度、变温、饥饿、及改变盐度为诱发条件，研究蒙古裸腹溞有性生殖和休眠卵的产生规律.实验结果表明种群密度是改变生殖方式和诱导产生休眠卵的最重要条件.当种群密度在1.4个/cm

Effect studies of some environmental conditions on reproductive conversion of Moina mongolica,a salt water cladocera

Reproduction conversion and dormant eggs inducement of Moina mongolica were studied under laboratory conditions by controlling population density, temperature variation, starvation and salinity fluctuation. Population density was the most important factor in changing procreation and inducing resting eggs of Moina mongolica among the factors controlled. When population density was 1.4 ind/cm3, reproduction of the animal was dominated by parthenogenetic individuals. When population density increased to 2 and 3.2 ind/cm3, male began to appear and occupied the population percentage of 3% and 14.5%, respectively. After then the density declined, sexual individuals (including male and female) increased with maximum 60% and resting eggs were found. Temperature (16, 18 and 32℃) played an important role in inducing dormant eggs but only occurred in the experiment group of lower temperature. Starvation was also a factor inducing dormant eggs. When food in environment was sparse, male individual can be found (fed with Chlorella spp. ,5 × 103ind/cm3, cells) and dormant eggs found at food density of 2 × 103ind/cm3, cells. The fluctuation of salinity seemed no effect on the reproduction conversion in the present experiments.