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

Variation 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 ...

即便在遗传背景与环境背景均一致的个体之间，种群内个体成熟时的年龄与体重差异也普遍存在。利用随机模型（stochastic model）解释这类个体差异，对于估算最优进化策略以及理解生活史性状（life history trait）间潜在的权衡关系至关重要。然而，现有多数研究所采用的随机模型，要么是现象学模型，要么仅能解释单一生活史性状的变异。本研究基于烟草天蛾（Manduca sexta）的发育生物学特性，提出了一种可同时刻画成熟时年龄与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，描述了取食行为以及昆虫共有的发育过程，其中包括蜕皮前保幼激素（juvenile hormone）的降解过程。本研究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时年龄与体重分布的影响。研究发现，其联合分布……