单独隔离孵化对镇海林蛙蝌蚪生长发育、社交行为和运动表现的影响

两栖类胚胎呈卵群一起孵化在反捕食、维持胚胎间的温度平衡和促进胚胎的同步发育等方面具有重要作用。在实验条件下探究孵化条件(单独隔离孵化和卵群一起孵化)对镇海林蛙(Rana zhenhaiensis)蝌蚪的生长发育、社交行为及其运动表现能力的影响。结果表明,孵出2天后,单独隔离孵化组蝌蚪的体长和发育历期均显著大于卵群一起孵化组。以体长为协变量的协方差分析表明,特定体长的单独隔离孵化组蝌蚪的体宽和体重均显著大于卵群一起孵化组的个体。在蝌蚪的活动行为中,单独隔离孵化组蝌蚪在水体上层和中层出现的频次显著小于卵群一起孵化组,而在水体底层的出现频次显著大于卵群一起孵化组。单独隔离孵化组蝌蚪个体的分布面积率、最近邻个体的距离、个体间的距离均显著大于卵群一起孵化组,但个体间的接触频次显著小于卵群一起孵化组。在运动表现方面,单独隔离孵化组胚胎的摆尾搏动频次显著小于卵群一起孵化组。单独隔离孵化组蝌蚪的运动时长和运动频次均显著小于卵群一起孵化组。本研究结果将为无尾两栖类幼期的生长发育规律提供参考数据。

Effects of isolated-incubation embryos on the growth, development, social behavior, and locomotor performance of Rana zhenhaiensis tadpoles

Embryo-clustering incubation plays an important role in anti-predation, maintaining temperature balance between embryos, and promoting hatching synchrony for anurans. In this study, we investigated the effects of two hatching conditions (isolated-incubation and clustered-incubation) on the growth, development, social behavior, and locomotor performance of Rana zhenhaiensis tadpoles under laboratory conditions. Our results showed that both body length and the Gosner development stage of two-day-old hatchlings in a single-embryo treatment were significantly larger than those of the group-embryo treatment. The results of the ANCOVA (with body length as the covariate) analysis showed that both body width and body mass in the group-embryo treatment were significantly lower than those of the single-embryo treatment. For tadpole activity behavior, the occurrence frequency in the upper and middle water layers in the single-embryo treatments were significantly lower than those of the group-embryo treatment, whereas it was significantly greater in the single-embryo treatments than that of the group-embryo treatment in the lower water layers. The proportion of area occupied by tadpoles, the nearest neighbor distance, and the distance among individuals in the single-embryo treatment were both significantly greater than those of the group-embryo treatment, but the contact frequency between pairwise tadpoles was significantly lower than those of the group-embryo treatment. Regarding locomotor performance, we found that activity duration and activity frequency in the single-embryo treatment were significantly lower than those of the group-embryo treatment. These findings should provide valuable reference data on the growth and development of Rana zhenhaiensis, as well as other anuran species.