Multivoltine insects are capable of producing multiple generations in one year. Favorable conditions support more generations, leading to serious outbreaks. For herbivorous insects, plant nutrient availability is a major environmental factor affecting fitness and it can shift substantially throughout seasons. Most organisms can adopt several strategies to regulate their nutrient intake and maximize performance in a variable environment. However, data regarding nutrient regulation of wild herbivores are scarce, and even more so regarding potential intergenerational plasticity. To bridge this gap, we measured nutritional regulation and performance of an outbreaking multivoltine herbivore, the Senegalese grasshopper (Oedaleus senegalensis). We surveyed a field population in Senegal and measured its nutritional preference and regulation across two generations (G1 and G3) using artificial diets and plant choice experiments. We found that not only G1 and G3 locusts selected different protein:carbohydrate ratios, but also that the strength of regulation was different. G1 locusts regulated their nutrient target more tightly than G3 locusts. In contrast, most studies with laboratory colonies have found that across generations, grasshoppers tend to have strong and consistent nutrient regulation. Both generations selected a carbohydrate-biased nutrient ratio, although it was more carbohydrate-biased for G3 locusts. However, plant nutrient contents in the field were more protein biased than their preferred diet. G1 females were heavier and laid more eggs than G3 females. However, G3 locusts survived longer during the experiment, suggesting a potential generational trade-off between reproduction and survival. Our results provide important insight on the interplay between nutrient availability in the field, nutrient regulation strategies, and performance in the context of outbreaks and persistence of populations.