生活周期毒性试验动物─—方形网纹溞的生物学

在实验室条件下研究方形网纹的生物学.试验时水温25±1℃,饲以斜生栅藻.初生幼体平均体长0.40mm,第1成龄0.96mm,最大体长可达1.45mm,体长增长(1_t,单位mm)与年龄(t,d)的关系可以表达为1t=1.43-e-0.268t,平均寿命22.73(17.10-25.00)d,其中包括3个幼龄和13个成龄.在3.91d达到性成熟.7d内生殖3胎,产仔40(19-47)个.一生生殖222.0个幼体,平均每胎18.5(4.8-23.6)个.生殖量最大出现在第6成龄.这时的年龄11.05d,体长1375mm.从初始10个个体的种群计算,种群生长曲线呈Logistic型,可以如下表达 y=2220/1+e6.239-0.572t 式中y表示总个体数,t表示时间(d).内禀增长能力(rm)为0.540/个/d,净增殖率(Ro)147.360/世代,世代平均周期(T)9.246d,周限速率(λ)1.716/个/d.  

BIOLOGY OF CERIODAPHNIA QUADRANGULA,(O.F.MULLER),AN EXPERIMENTAL ANIMAL FOR LIFE-CYCLE TOXICITY TEST

Biology of parthenogenetic females of Ceriodaphnia quadrangula(O.F.Muller)wasstudied under laboratory conditions at 25±1℃,Scenedesmus obliquus(Turp.)Kutz wasused as food for the animals during the experiments. The mean body -length of neonatesof C. quadrangula was 0.40mm and that of the first adult instar 0.96mm,A maximumlength of 1.45mm was attained.The growth in body─length(lt,in mm)in relation to age(t,in day)can be described as lt=1.43-e-0.268tThe mean longevity was found to be 22.73(17.10─25.00)days for 3 preadult and 13adult instars.Sexual maturity was reached in 3.91 days.40(19─47)young from 3 broods wereobtained in 7 days.The mean number of young per brood was 18.5(4.8─23.6).The totaloffspring production by one adult reached 222.1 during its life─span. The maximum re-production period occurred during the 6th adult instar. At this age,the animals were11.05 days old,and had a body length of 1.375mm.In a population originated from 10 individuals,the population growth curve of C. quadrangula was shown to be logistic and may be expressed as y=2220/1+e6.239-0.572t in which y denotes total number of individuals and t, days.The innate capacity for increase(rm)was 0.540 per female per day,the net repro-duction rate(Ro)was 147.360 per generation, the mean length of a generation(T)was9.246 days, and the finite rate ofincrease(λ)was 1.716 per female per day.