Comparison of three models predicting developmental milestones given environmental and individual variation

Area of Science:

• Ecology and Evolutionary Biology
• Mathematical Biology
• Entomology

Background:

• Phenotypic variability is essential for organismal evolution.
• Environmental temperature directly influences the phenology of poikilothermic (cold-blooded) organisms.
• Existing phenology models may not fully capture individual and environmental variability.

Purpose of the Study:

• To compare existing phenology models (distributed delay and Sharpe and DeMichele) with a newly developed model.
• To introduce the Extended von Foerster model, based on the age-structured McKendrick-von Foerster partial differential model.
• To evaluate each model's capacity for incorporating inter-individual and environmental variability.

Main Methods:

• Theoretical comparison of biological assumptions underlying different phenology models.
• Development of the Extended von Foerster model.
• Validation against laboratory developmental data for mountain pine beetle (Dendroctonus ponderosae).

Main Results:

• The Extended von Foerster model was developed, integrating age-structure and variability.
• Theoretical analysis highlighted differences in how models handle variability.
• The Extended von Foerster model demonstrated the highest correlation between theoretical predictions and observed developmental data under constant temperature conditions.

Conclusions:

• The Extended von Foerster model offers a more accurate theoretical framework for predicting phenology in variable environments.
• Accounting for both individual and environmental variability is critical for accurate phenological modeling.
• This approach has significant implications for understanding insect development and population dynamics.