Semlitsch Raymond D
Savannah River Ecology Laboratory, University of Georgia's, P.O. Drawer E, 29801, Aiken, SC, USA.
Oecologia. 1985 Feb;65(3):305-313. doi: 10.1007/BF00378903.
The reproductive strategy of the salamander Ambystoma talpoideum was studied on an age-specific basis in five breeding populations using ponds subjected to different annual probabilities of drying. Ambystoma talpoideum is facultatively paedomorphic in semi-permanent ponds but sexually mature individuals occur only as terrestrial morphs in temporary ponds. Larvae of paedomorphs and terrestrial morphs mature at the same age but different body sizes. Body mass and snout-vent length increased with age in both morphs. One-year old terrestrial morphs had larger snoutvent lengths than 1-year-old paedomorphs but were smaller in body mass. Clutch mass, number of ova, and diameter of ova increased with snout-vent length. After removing the effects of snout-vent length with an analysis of covariance, only the diameter of ova and the resultant clutch mass increased with age. One-year-old terrestrial morphs produced more ova than 1-year-old paedomorphs but paedomorphs have the potential to reproduce earlier than terrestrial morphs. Parental investment, as shown by the relationship between clutch size and egg size, increased with age. This suggested that as potential energy increased with age, A. talpoideum produced more eggs and larger eggs. Rather than optimizing egg size, individuals may produce a range of egg sizes that theoretically fare better in spatially and temporally varying environments.
在五个繁殖种群中，基于年龄特异性，利用经历不同年度干涸概率的池塘，对墨西哥钝口螈的繁殖策略进行了研究。墨西哥钝口螈在半永久性池塘中是兼性幼态持续的，但性成熟个体仅在临时性池塘中以陆生成体形态出现。幼态持续个体和陆生成体的幼体在相同年龄成熟，但体型大小不同。两种形态的体重和吻肛长度均随年龄增长。一岁的陆生成体吻肛长度比一岁的幼态持续个体长，但体重较小。卵块质量、卵子数量和卵子直径随吻肛长度增加。在用协方差分析去除吻肛长度的影响后，只有卵子直径和由此产生的卵块质量随年龄增加。一岁的陆生成体比一岁的幼态持续个体产生更多卵子，但幼态持续个体有比陆生成体更早繁殖的潜力。如卵块大小与卵大小之间的关系所示，亲代投资随年龄增加。这表明，随着潜在能量随年龄增加，墨西哥钝口螈会产出更多和更大的卵。个体可能并非优化卵的大小，而是产出一系列理论上在空间和时间变化的环境中表现更好的卵大小。
