Effects of Rearing Density on Growth, Adult Emergence and Survival in the Edible Cricket Gryllodes sigillatus

ABSTRACT

Gryllodes sigillatus is an increasingly important species in edible insect production, yet the optimal rearing density for this species under commercial conditions remains poorly defined. This study evaluated the effects of five rearing densities (1.5, 2, 2.5, 3 and 4 mL of newly hatched nymphs, corresponding to approximately 0.144–0.385 crickets/cm ² ) on survival, adult emergence, mean individual body weight, absolute number of adults and residual nymphs and total biomass per container in a completely randomized design with nine replicates per treatment. At Day 60, rearing density affected all measured variables except total biomass per container. Adult emergence probability declined progressively with increasing density, from 0.422 at 1.5 mL to 0.175 at 4 mL, while mean individual body weight was higher at the two lowest densities compared to all higher treatments. Survival probability was significantly reduced only at the highest density tested (4 mL) relative to 2.5 mL. The absolute number of adults per container was significantly greater at 2.5 mL than at 1.5 and 2 mL, reflecting the compensatory effect of larger initial cohort size. Conversely, the number of residual nymphs increased markedly with density, indicating progressive developmental delay under crowded conditions. Total biomass did not differ across treatments, demonstrating that gains in individual weight at low density were offset by lower absolute survival, rendering total yield effectively density‐independent within the range tested. These results reveal that the identity of the optimal rearing density depends on the production objective: within the range tested, 1.5 mL maximises individual quality and developmental completeness, while 2.5 mL maximises absolute adult yield per container, though lower densities than those evaluated here may further improve individual performance.