Grüner Cornelia, Sauer Klaus Peter
Lehrstuhl für Evolutionsforschung, Fakultät für Biologie, Universität Bielefeld, Universitätsstrasse 1, D-4800, Bielefeld 1, Federal Republic of Germany.
Oecologia. 1988 Jan;74(4):515-523. doi: 10.1007/BF00380048.
A highly specific recognition system, capable of "foreseeing" and distinguishing between two critical points in time, exists in Mamestra brassicae (Lepidoptera: Noctuidae). Both points in time, the onset of a drought period and the end of the growth season, require different growth patterns of the pupae. In order to minimize the likelihood of weather-induced mortality and to maximize fitness, individuals of M. brassicae must enter aestival dormancy or hibernal diapause, respectively, before the onset of drought or frost. This study is primarily concerned with aestival dormancy. Normally, the pupal period of dormancy-free developing individuals amounts to approximately 20 to 30 days. A modified pupal period of approximately 35 to 80 days is defined as aestival dormancy. The onset of aestival dormancy is triggered by day lengths exceeding an innate individaul-specific threshold. The results reported in this paper indicate that the photoperiodic response curve represents largely the genetic variability within a population with respect to the thresholds triggering aestival dormancy. This variability in thresholds is considered to reflect the frequency of correlation of a distinct day length with a certain onset of drought period in the past. Furthermore, the innate thresholds are characterized by a temperature dependent norm of reaction. Our results also indicate, that a strong genetical component is involved in variability of duration of the pupal period. This variability in duration of aestivation reflects the frequency of drought periods of a certain length in the past. The adaptive significance of both the variation in day length thresholds and duration of aestival dormancy is discussed with respect to the number of generations per season, and the synchronization of the individual life cycles with the seasonal changing environmental conditions.
在甘蓝夜蛾（鳞翅目：夜蛾科）中存在一种高度特异的识别系统，它能够“预见”并区分两个关键时间点。这两个时间点，即干旱期的开始和生长季节的结束，需要蛹呈现出不同的生长模式。为了将天气导致的死亡可能性降至最低并使适应性最大化，甘蓝夜蛾个体必须在干旱或霜冻来临之前，分别进入夏眠或冬眠滞育状态。本研究主要关注夏眠。通常，无休眠发育个体的蛹期约为20至30天。将约35至80天的延长蛹期定义为夏眠。夏眠的开始由超过个体固有阈值的日长触发。本文报道的结果表明，光周期反应曲线在很大程度上代表了种群内关于触发夏眠阈值的遗传变异性。这种阈值的变异性被认为反映了过去特定日长与特定干旱期开始之间的关联频率。此外，固有阈值具有温度依赖的反应规范特征。我们的结果还表明，蛹期持续时间的变异性涉及强大的遗传成分。夏眠持续时间的这种变异性反映了过去特定长度干旱期的频率。本文从每季节世代数以及个体生命周期与季节性变化环境条件的同步性方面，讨论了日长阈值变化和夏眠持续时间的适应性意义。
