Nutritional legacies across space and time: evidence for a nutritional ecotype in large herbivores

Nutrition is the foundation of life and yet, resources are finite. For wild animals, variation in resources and risk across time and space has resulted in a wide array of adaptations that allow individuals to meet daily metabolic and nutritional needs, including seasonal changes in metabolism, capital stores, and diverse reproductive strategies. For long-lived, iteroparous mammals, resources should be obtained, allocated, and stored in a way that balances current needs and yet, is sensitive to future requirements for survival. We propose that risk-sensitive allocation of energy is the mark of a nutritional legacy associated with an anticipatory adaptation of seasonal and variable environments. Here, we synthesize how nutritional legacies are interwoven into the very existence and life history of large ungulates, and how the accumulation of nutritional legacies across lifetimes and generations emerges into a nutritional ecotype. We describe nutritional ecotypes as the integrated profile of how large ungulates anticipate, acquire, store, and allocate energy across temporal scales, from daily decisions to evolutionary history. The annual fat cycle of ungulates, although affected by environmental conditions, is an anticipatory outcome of risk-sensitive allocation of resources anchored in metabolic programming within the context of a specific environment and the life history of a species or sex. Refinement in risk-sensitive allocation across days, seasons, lifetimes, and generations yields an important life-history adaptation that enables animals to align resource acquisition and allocation with the specific environments they occupy. Energetic strategies of wild animals are both a product of past experiences and the anticipation of the risks and resources that will occur in the future; the shaping of a nutritional ecotype in wild ungulates is itself an adaptation to local environments. We contend that further appreciation for nutritional ecotypes holds potential to advance our understanding of how large ungulates will persist or fail to, in our ever-changing world.