DOES IMMUNE CHALLENGE AFFECT NUTRITIONAL INTAKE OF COCKROACHES (BLAPTICA DUBIA)?

September 2018 - June 2019
Supervisor: Dr Sheena Cotter

Nutrition is critical to the immune defence of organsisms and the survival of species. Immune challenged individuals are likely to adjust their intake of protein and carbohydrates to a self-select a diet that maximises survival. Quantification of these dietary requirements is lacking in the literature, but crucial for identifying evolutionary adaptations of species. This study used a dietary choice test, where both immune challenged and control Blaptica dubia cockroaches were presented with foods that ranged in their protein to carbohydrate ratios, to quantify the target intake of these macronutrients at two life stages (juvenile and adult). Individuals were then restricted to singular diets to quantify how protein and carbohydrate intake was prioritised under nutritional stress. Juvenile cockroaches displayed a preference for protein, whereas adults foraged to maximise calorie consumption regardless of macronutrient composition. Contrasting to the majority of literature, immune challenged cockroaches displayed a preference for carbohydrates, highlighting a potential immune regulatory response. Consuming less protein may restrict pathogens of the necessary nutrients required for growth, meaning it has less chance of survival in a host. It is important to consider the specific host-pathogen species interaction to deduce the mechanisms of nutritional regulation. Understanding how nutritional regulation changes with different physiological states is important for predicting how animals will cope with changes in their environment.