Comparative Nutritional Immunology: The Desert Locust as a Model for Macronutrient Influence on Immune Function Across Species

Understanding the impact of macronutrient consumption on immune function across species has broad implications for both ecological and biomedical research. This paper presents a comparative analysis between desert locust (Schistocerca gregaria) and various vertebrate models, focusing on how diet modulates immune responses to pathogenic infections. Previous research demonstrated that desert locusts infected with Metarhizium robertsii fungal pathogen exhibited increased resistance when fed a carbohydrate-biased diet compared to those on a protein-biased diet. This observation parallels findings from invertebrate and vertebrate models, including fruit flies (Drosophila melanogaster), mice (Mus musculus) and chickens (Gallus gallus). Studies with D. melanogaster found that the protein:carbohydrates intake ratio can alter the expression of immune-related genes and modify an organism's resistance to fungal pathogens. Studies in mice have shown that carbohydrate-rich diets improve immune resilience and reduce susceptibility to viral infections like influenza, whereas protein-dominant diets can exacerbate disease outcomes. Similarly, in chickens, balanced diets with adequate carbohydrates support mucosal immunity and help control Salmonella colonization. By comparing immune responses across these taxonomic groups, we highlight the evolutionary conservation of nutritional immunology and justify the use of desert locusts as a complementary model for studying macronutrient-driven immune mechanisms. This cross-species perspective can inform human health interventions, particularly in optimizing diet for better health outcomes.