有性生殖对萼花臂尾轮虫(Brachionus calyci florus)种群适合度影响的初步研究

EFFECT OF SEX ON POPULATION FITNESS OF THE ROTIFER BRACHIONUS CALYCIFLORUS

利用萼花臂尾轮虫(Brachionus calyciflorus)探讨了在不同温度下有性生殖种群是否表现出较高的适合度,这种优势是否在形态上有所体现.观察并比较了有性生殖和孤雌生殖种群在15,25和35℃条件下的净生殖率(R0)、内禀增长率(rm)(适合度参数)以及个体的5项形态学指标(背甲长、背甲宽、中棘刺长、中棘刺间距和侧中棘刺间距).结果表明,有性生殖种群的适合度显著高于孤雌生殖种群(P<0.05);有性生殖种群个体的大小显著小于孤雌生殖种群个体(P<0.05),这也是导致有性生殖种群具有较高适合度的原因之一.

The effect of sex on the mean fitness of population at different temperatures by using the monogonont rotifer, Brachionus calyciflorus is examined. Here, the temperatures used are 15, 25 and 35℃. Net reproduction rate （R0） and intrinsic increasing rate （rm） （i. e. , fitness） are measured at all temperatures. Five morphologic indices are measured, they are length, width, length of median spines, distance between median spines and distance between median and lateral spines, to see if the individuals of sexual populations also have superiority on morphology. The results show that the sexual populations at each temperature all show greater fitness than parthenogenetic populations; the body size of individuals in sexual population is significantly smaller than that in parthenogenetic population, which is one of the main reasons resulting in higher fitness in sexual populations.