Niche is one of the most important concepts in ecology. Its characterization ranges from a purely abstract form often for mathematical convenience, to an empirically-derived form from correlation between physical and occurrence variables. In between, energy budget models use energy as the underlying variable for niche construction and combine mathematical models with empirical measurements. However, energy budget models are often used to understand a single and well-studied species and thus cannot be extrapolated. I will present a mathematical model that focuses on understanding the relative importance of processes that shape the energy budget of income-breeding insects. In this talk, I define performance as the net energy gain that is the difference between energetic gain and energetic cost. My model assesses how performance varies with respect to body size, behavior, temperature, and resource availability and quality. More specifically, I ask whether performance breadth as a function of temperature increases or decreases with body size.
Results/Conclusions
I find that large bodied individuals can have either wider or narrower performance breadth then do smaller individuals. The upper limit of the thermal niche is principally determined by ecological factors such as how foraging rate scales with body size, whereas the lower limit is shaped by behavioral and physical constraints. I also find that intermediate body size attains maximal performance under a narrow range of resource quality, not quantity. In short, the model exhibits numerous scenarios of how niche differs among body sizes. Distinguishing these scenarios requires more specific information such as how foraging rate changes with body size, accurate distribution of resource quantity and quality, and behavior.