Tenhumberg B, Tyre A J, Roitberg B
Department of Biological Sciences, Behavioural Ecology Research Group, Burnaby, BC, V5A 1S6, Canada.
J Theor Biol. 2000 Feb 21;202(4):257-72. doi: 10.1006/jtbi.1999.1049.
Variation in mean food availability, and in the variance around the mean, affects the growth rate during development. Previous theoretical work on the influence of environmental quality or growth rates on the phenotypic traits age and size at maturation assumed that there is no variation in growth rate or food availability within a generation. We develop a stochastic dynamic programming (SDP) model of the foraging behaviour of aphidophagous syrphids, and use this model to predict when syrphids should pupate (mature) when average food availability changes, or varies stochastically, during development. The optimal strategy takes into account not only the availability of food, but also the timing of its availability. Food availability, when small, influences developmental time, but not weight at pupation. Food availability, when large, influences weight at pupation, but not developmental time. When the food supply is low, the optimal strategy adjusts the size at pupation downwards for stochastic as opposed to deterministic availability of food. The conclusions reinforce the need for life-history studies to consider state dependence and short-term variability in growth rates.
平均食物可获得量的变化以及围绕平均值的方差，会影响发育过程中的生长速率。先前关于环境质量或生长速率对成熟时表型特征年龄和大小影响的理论研究假定，一代内生长速率或食物可获得量不存在变化。我们构建了一个食蚜食蚜蝇觅食行为的随机动态规划（SDP）模型，并使用该模型预测在发育过程中平均食物可获得量发生变化或随机变化时，食蚜蝇何时应该化蛹（成熟）。最优策略不仅考虑食物的可获得性，还考虑其可获得的时间。少量的食物可获得量会影响发育时间，但不会影响化蛹时的体重。大量的食物可获得量会影响化蛹时的体重，但不会影响发育时间。当食物供应较低时，最优策略会针对随机而非确定性的食物可获得性向下调整化蛹时的大小。这些结论强化了生活史研究考虑生长速率的状态依赖性和短期变异性的必要性。
