Abstract The conditions experienced during development may influence adult cognition and fitness, especially when conditions are stressful. To test the developmental stress hypothesis, I manipulated Texas field crickets (Gryllus texensis) juvenile diet and observed its effects on cognition (Chapter 1) and other fitness-related traits; I also examined whether diet influenced trade-offs between traits (Chapter 2). Individuals improved their cognition scores with training, but not during the test trial, suggesting developmental diets were stressful, hindering spatial cognition. Female fecundity was greatest in larger females that grew quickly. Males that developed quickly and performed well cognitively had a high probability of adopting a caller strategy; these males also exhibited high calling effort, suggesting high overall condition. For all others, adopting a caller strategy and exhibiting high calling effort only occurred with trade-offs, either via slower development, poorer performance in the cognitive task, or both. Diet did not predict cognitive and reproductive trade-offs.