密度对大蹼铃蟾蝌蚪生长发育和存活率的影响初探

A Preliminary Study of Density Effects on the Growth and Survival Rate of Bombina maxima Tadpoles

为了分析密度对大蹼铃蟾Bombina maxima蝌蚪生长发育和存活率的影响,将大蹼铃蟾蝌蚪分别饲养在A组(30只/L)、B组(60只/L)和C组(90只/L)3个不同的密度条件下,每天定时定量喂食和换水,每隔5 d测量和记录1次蝌蚪的全长、尾长、体宽和死亡数,并用相关性和线性回归进行分析。结果表明:密度与全长、尾长和体宽都具有显著的负相关性(P<0.05),相关性系数r值为:A组<B组<C组;以各组密度为自变量,大蹼铃蟾蝌蚪全长、尾长和体宽为因变量的线性回归斜率表现为:A组<B组<C组。大蹼铃蟾蝌蚪的生长率随密度的增加而减小。密度与存活率具有显著相关性(r=0.877,P<0.01),存活率在饲养早期较高,中后期逐渐降低,且高密度下的存活率始终小于低密度。推测高密度饲养下的大蹼铃蟾蝌蚪较早进入变态期,且密度越大,蝌蚪进入变态期时的全长、尾长和体宽越小。

In order to analyze the effect of density on the growth and survival rate of Bombina maxima tadpoles,tadpoles were respectively raised under 3 different density conditions:group A(30 ind./L),group B(60 ind./L),and group C(90 ind./L).Food feeding and water changing were conducted at the fixed time each day,and then the total length,tail length,body width and number of deaths of the tadpoles were measured and recorded every 5 days.The results of correlation and linear regression analysis showed that the density was significantly negatively correlated with the total length,tail length and body width(P<0.05),and the correlation coefficient value was group A<group B<group C.Taking the density of each group as the independent variable and the total length,tail length and body width as the dependent variables,the linear regression slope relationships were group A<group B<group C.The results of correlation and regression analysis showed that the growth rate of the B.maxima tadpole decreased along with the increasing of density,that is,the higher of density,the smaller of growth rate.Moreover,there was a significant correlation between density and survival rate(r=0.877,P<0.01).The survival rate of each group was higher in the early stage but gradually decreased in the middle and late stages,and the survival rate under high-density feeding condition was always lower than that under low-density.These findings indicated that B.maxima tadpoles under high-density feeding condition entered metamorphosis stage earlier,and the larger of feeding density,the smaller of total length,tail length and body width when the tadpoles entered the metamorphosis stage.