Population dynamics and body‐size selection in Daphnia
Population dynamics and body‐size selection in Daphnia
复制标题
水蚤的种群动态和体型选择
DOI：
--
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
M. Leibold
中科院分区：
文献类型：
--
作者：
A. J. Tessier;A. Young;M. Leibold
我们研究了遭受强烈脊椎动物捕食的帽状溞种群的种群动态和体型的季节性变化。食物限制的强度通过就地食物添加进行季节性量化。我们还在夏初和夏末收集活体动物进行实验室研究，旨在估计种群生活史特征的遗传变异和季节性变化。人口的特点是短期出生率和死亡率几乎相等，与人口密度密切相关，表明存在密度依赖性。人群普遍表现出非常高的出生率和死亡率，并且对实验性食物添加没有显着反应。唯一的例外是 1988 年 6 月，当时人口密度很高，并且表现出强烈的食物限制。在这两个夏天，成年人的最小和平均体型都有所下降。实验室研究记录了初夏采集的动物体型和其他生活史特征的显着遗传变异。然而，到夏末，这些相同特征几乎没有遗传变异。此外，夏初收集的克隆在出生和成熟时的体型在遗传上比夏末收集的克隆更大。我们将这些结果解释为表明身体尺寸的自然选择。
We examined the population dynamics and seasonal change in body size of a population of Daphnia galeata mendotae experiencing strong vertebrate predation. The intensity of food limitation was quantified seasonally by in situ food addition. We also collected live animals early and late in the summer for laboratory studies designed to estimate genetic variation and seasonal change in life-history traits for the population. The population was characterized by nearly equal short-term birth and death rates that were strongly correlated with population density, suggesting density dependence. The population generally exhibited very high birth and death rates and no significant response to experimental food addition. The one exception was June 1988, when the population achieved high densities and exhibited strong food limitation. Throughout both summers, minimal and average body sizes of adults decreased. Laboratory studies document substantial genetic variation for body size and other life-history traits among animals collected early in summer. By late summer, however, there was little genetic variation for these same traits. Furthermore, clones collected early in summer were genetically larger in body size at birth and maturity than clones collected in late summer. We interpret these results as indicating natural selection for body size.