De Meester Luc
Laboratory of Animal Ecology, University of Ghent, K.L. Ledeganckstraat 35, 9000, Gent, Belgium.
Oecologia. 1994 Apr;97(3):333-341. doi: 10.1007/BF00317323.
To test the hypothesis of co-adaptation of life histories and daytime vertical distribution (vertical migration behaviour) in Daphnia, life history characteristics were analysed for two positively, three negatively, and four intermediately phototactic Daphnia magna clones. Clones with different phototactic behaviour were found to have divergent life history strategies, with positively phototactic clones being good exploiters under the non-limiting conditions provided in the laboratory, i.e. low density (1 ind./1), high food concentration (6,5-7 10 Scenedesmus cells/ml, restored daily) and high temperature (20° C). They realized a high intrinsic rate of increase at a small adult body size through rapid development, at a cost of producing small neonates. Negatively and intermediately phototactic clones had larger adult body sizes, and produced larger neonates that were more starvation-resistant than those of positively phototactic clones. Selection for high intrinsic rate of increase in intermediately phototactic clones was mediated through the production of large clutches.
为了验证水蚤生活史与日间垂直分布（垂直迁移行为）共同适应的假说，对两个正向趋光、三个负向趋光和四个中间趋光的大型溞克隆进行了生活史特征分析。发现具有不同趋光行为的克隆具有不同的生活史策略，正向趋光克隆在实验室提供的非限制性条件下，即低密度（1只/1）、高食物浓度（6.5 - 7×10个斜生栅藻细胞/毫升，每日补充）和高温（20℃）下，是良好的开拓者。它们通过快速发育在较小的成体体型下实现了较高的内禀增长率，代价是产出的幼体较小。负向趋光和中间趋光克隆的成体体型较大，产出的幼体也较大，且比正向趋光克隆的幼体更耐饥饿。中间趋光克隆通过产出大量卵来实现对高内禀增长率的选择。
