Does body growth impair immune function in a large herbivore?

Area of Science:

• Ecology
• Evolutionary Biology
• Immunology

Background:

• The principle of allocation suggests resource trade-offs between biological functions like growth, immunity, reproduction, and survival.
• Energetically costly functions, such as growth and immunity, may compete for limited resources.
• The impact of high growth allocation on immune system development and performance in wild mammals is not well understood.

Purpose of the Study:

• To investigate potential costs of growth on immune phenotype in roe deer (Capreolus capreolus) over short-term (growth period) and long-term (adulthood).
• To examine trade-offs between growth and 12 immune traits reflecting innate and adaptive responses.
• To compare these relationships across different environmental conditions, sexes, and populations.

Main Methods:

• Studied three roe deer populations with contrasting environmental conditions.
• Assessed 12 immune traits (innate and adaptive) in relation to growth rates.
• Analyzed immune phenotype costs over an individual's lifespan, considering sex and population differences.

Main Results:

• Fast growth was weakly associated with lower humoral (globulin) and some cellular (eosinophil, neutrophil) immune traits.
• Overall evidence for significant growth-related costs on immunity was limited.
• No detectable growth costs on immunity were observed in females from the most challenging environment.

Conclusions:

• Resource allocation strategies between growth and immunity are complex and context-dependent in wild mammals.
• Environmental conditions can modulate or mask potential trade-offs between growth and immune function.
• Further research is needed to understand the interplay of reproduction, maintenance, and immunity under varying ecological pressures.