黑斑侧褶蛙蝌蚪断尾后的补偿生长和发育研究

动物在经历不利的生长条件或环境后往往出现补偿生长。研究了黑斑侧褶蛙(Pelophylax nigromaculatus)蝌蚪经历来自食蚊鱼(Gambusia affinis)捕食造成断尾损伤后的补偿生长模式、断尾损失对蝌蚪游泳能力以及变态时间与大小的影响。结果表明,经历捕食压力后,全尾组和1/3断尾组蝌蚪的体长显著大于1/2断尾组蝌蚪的体长,全尾组和1/3断尾组之间的蝌蚪体长差异不显著;第19天时,1/2断尾组蝌蚪经过补偿生长后体长显著大于全尾组蝌蚪,1/3断尾组与全尾组和1/2断尾组之间的蝌蚪体长差异均不显著;三个实验组之间蝌蚪尾长差异不显著;全尾组蝌蚪的疾游速显著大于1/2断尾组蝌蚪的疾游速,1/3断尾组蝌蚪的疾游速与全尾组和1/2断尾组之间差异不显著,表明严重断尾对蝌蚪疾游速产生了消极影响。三个实验组蝌蚪的变态时间和变态前后形态差异均不显著。黑斑侧褶蛙蝌蚪能够在变态前调整生长轨迹补偿早期捕食风险造成的生长损失,断尾损失并不影响变态时间与大小,断尾超过一半的蝌蚪经过补偿生长后仍要付出一定的运动代价。

Compensatory growth and development of tail loss in Pelophylax nigromaculatus Tadpoles

Many animals often undergo compensatory growth with adverse growth conditions or in hostile environments. We studied the growth trajectories of anuran tadpoles (Pelophylax nigromaculatus) with three tail length treatments, including full-tail, 1/3-tail loss and 1/2-tail loss inflicted by the predatory mosquitofish (Gambusia affinis). We also evaluated the effect of tail injury on the swimming performance and size and time at metamorphosis of the tadpoles. Our results showed that the body length of full-tail and 1/3-tail loss treatment tadpoles was significantly longer than that of the 1/2-tail loss tadpoles the day following predation stress, however, there were no significant differences between these two groups. On the 19th day, the body length of the 1/2-tail loss tadpoles was significantly longer than that of the full-tail tadpoles and there were no significant differences between the 1/3-tail loss and 1/2-tail loss tadpoles. No significant differences were found among groups in tail fin length of the tadpoles. The burst swimming speed of full-tail tadpoles was significantly faster than that of the 1/2-tail loss tadpoles and there were no significant differences in the swimming performance of tadpoles between the 1/2-tail and 1/3-tail loss groups. These results suggested that the performance in burst swimming of tadpoles was negatively affected when the tail is impaired seriously by the predators. The tadpoles from the three experimental groups almost synchronously achieved metamorphosis at a similar size. P. nigromaculatus tadpoles can adjust their growth trajectories to compensate for the growth loss caused by predator risk at the early development stage before metamorphosis. Although the tadpoles can compensate for the loss of almost half the tail, they must pay in locomotor costs.