Resonance-Induced Multimodal Body-Size Distributions

Background/Question/Methods

Body-size distribution of species is a major determinant of ecosystem structure and function. In natural habitats, size distributions are often multimodal with several peaks of abundant sizes. Previous studies suggested that the population of each peak fits to a particular niche. However, this cannot explain how, in many natural ecosystems, several packs coexist close to each other, and therefore do compete over the same niche.

Results/Conclusions

Here, we suggest an alternative, general mechanism for multimodal body-size distributions by showing that the size-dependent tradeoff between reproduction and resource utilization entails an inherent resonance that may induce multiple peaks, all competing over the same niche. Our theory is well-fitted to empirical data in various ecosystems, where both model and measurements show a multimodal, periodically-peaked distribution at larger sizes, followed by a smooth tail at smaller sizes. Based on the data, our theory suggests a universal pattern that governs regional size distributions at all scales.