Data from: A stochastic model for predicting age and mass at maturity of insects

AbstractVariation in age and mass at maturity is commonly observed in populations, even among individuals with the same genetic and environmental backgrounds. Accounting for such individual variation with a stochastic model is important for estimating optimal evolutionary strategies and for understanding potential trade-offs among life history traits. However, most studies employ stochastic models that are either phenomenological or account for variation in only one life history trait. We propose a model based on the developmental biology of the moth Manduca sexta that accounts for stochasticity in two key life history traits, age and mass at maturity. The model is mechanistic, describing feeding behavior and common insect developmental processes including the degradation of juvenile hormone prior to molting. We derive a joint probability density function for the model and explore how the distribution of age and mass at maturity is affected by different parameter values. We find that the joint distribution is generally non-normal and highly sensitive to parameter values. In addition, our model predicts previously observed effects of temperature change and nutritional quality on the expected values of insect age and mass. Our results highlight the importance of integrating multiple sources of stochasticity into life history models., Usage notesThis ZIP archive contains R files for simulating the stochastic maturation and growth model, and for evaluating the joint probability density function.

种群内普遍存在成熟年龄与成熟体重的个体差异，即便遗传背景与环境背景完全一致的个体亦不例外。借助随机模型对这类个体变异进行建模，对于估算最优进化策略、解析生活史性状间潜在的权衡关系至关重要。然而，当前绝大多数研究所使用的随机模型，要么仅为现象学模型，要么仅针对单一生活史性状的变异进行刻画。我们基于烟草天蛾（Manduca sexta）的发育生物学特征，提出了一种可同时刻画成熟年龄与成熟体重这两个关键生活史性状随机性的模型。该模型属于机制性模型，能够描述昆虫的取食行为以及常见发育过程，包括蜕皮前保幼激素的降解过程。我们推导了该模型的联合概率密度函数，并探究了不同参数取值对成熟年龄与成熟体重分布的影响。研究发现，该联合分布通常呈非正态分布，且对参数取值具有高度敏感性。此外，本模型可复现此前已观测到的温度变化与营养质量对昆虫成熟年龄与成熟体重预期值的影响效应。本研究结果凸显了将多源随机性整合至生活史模型中的重要性。
使用说明：此ZIP压缩包包含用于模拟随机成熟与生长模型、并评估联合概率密度函数的R脚本文件。