Applying nutritional ecology to optimize diets of crickets raised for food and feed

Increasing yield is a primary goal of mass insect rearing for food and feed, and diet impacts insect life-history traits that affect yield, such as survival, development time and body size. However, experiments rarely test the nutritional requirements of insects from hatch to adulthood, and so little is known about how the full developmental macronutrient intake impacts the survival, growth and adult body size of mass-reared insects. Here, we applied the nutritional geometry framework and reared individual tropical house crickets (Gryllodes sigillatus) from hatch to adulthood on a wide range of protein : carbohydrate diets. We measured weekly food consumption, survival, development time to adulthood and adult body size and mass, and calculated a yield metric to extrapolate our individual-level results and predict how diet influences yield at the mass-rearing level. Yield was maximized on a 3_P : 1_C diet, as crickets fed this diet were most likely to develop into adults and grew maximum mass and body size. When provided with a choice between diets, crickets selected a relatively balanced 1.05_P : 1_C diet throughout development, but males consumed 17% more protein than females. Our results represent a crucial first step towards determining the optimal standard feed formulation required to maximize cricket farming yield.