On the Allometric Scaling of Resource Intake Under Limiting Conditions

Individual resource intake rates are known to depend on both individual body size and resource availability. Here, we have developed a model to integrate these two drivers, accounting explicitly for the scaling of perceived resource availability with individual body size. The model merges a Kleiber-like scaling law with Holling functional responses into a single mathematical framework, involving both body-size the density of resources. When the availability of resources is held constant the model predicts a relationship between resource intake rates and body sizes whose log-log graph is a concave curve. The significant deviation from a power law accounts for the body size dependency of resource limitations. The model results are consistent with data from both a laboratory experiment on benthic macro-invertebrates and the available literature.