A1384
Title: Estimating parameters in allometric growth differential-equation models
Authors: Hideyasu Shimadzu - Kitasato University (Japan) [presenting]
Abstract: Differential equations have long played a pivotal role in modelling growth and energy allocation patterns in living organisms. Parameter estimation, however, is often challenging because biologically interpretable models rarely admit closed-form solutions. A unified allometric differential-equation model is presented whose parameters are estimable solely from body-growth data, drawing on ideas from functional data analysis. The framework reconstructs underlying life-history trajectories from longitudinal observations using non-parametric smoothing and subsequently infers energy-allocation dynamics through differential-equation constraints. Using the water flea Daphnia magna as a model organism, stochastic temperature fluctuations are shown to generate life-history trajectories resembling those observed under chronically elevated temperatures. The model further demonstrates, through Jensen's inequality, that temperature variability systematically shifts the balance between somatic and reproductive allocation, producing reproductive responses that cannot be inferred from growth data alone. By integrating mechanistic allometric relationships with stochastic temperature inputs and trajectory-based inference, the framework provides a tractable basis for parameter estimation and for biological interpretation of life-history responses under temperature variability.
