Controlling Black Soldier Fly Adult Emergence via Low-Temperature Storage

Industrial black soldier fly production requires precise synchronization of life cycles to ensure efficient breedingand egg collection. Variability in pupal emergence can cause overlapping generations and reduce processcontrol. This study evaluated low-temperature storage to delay pupal emergence, enabling batch alignment andimproved workflow in scalable industrial production. Approximately 6,000 individuals (>75 % pupae) from astandard growth cycle at 27 °C and 70 % relative humidity (RH) were used. Larvae were fed a wet Gainesvillehousefly diet (70% water) at 0.114 g larva⁻¹ day⁻¹. One week after harvest, at the onset of adult emergence,individuals were equally divided into six containers (1,000 individuals per container). Three replicates wereassigned to an “immediate emergence (IE)” treatment, in which containers were transferred directly to adultcages (30 × 30 × 30 cm) maintained at 27 °C, 70 % RH, and a 12:12 h LED light-dark cycle. The remaining threereplicates were assigned to a “delayed emergence (DE)” treatment, in which containers were stored at 17 °Cand 70 % RH for 12 days; based on preliminary observations indicating the onset of emergence at thistemperature before transfer to cages under the same conditions as the IE group. Eggs were collected every 2–3days over a 10-day reproductive cycle period following full adult emergence, corresponding to the peakoviposition phase. Total egg production and adult emergence rates were recorded and compared betweentreatments using independent samples t-tests. Total egg yield did not differ between treatments (IE: 6.14 ±0.69 g; DE: 5.70 ± 0.52 g), and adult emergence rates remained high and comparable in both groups (>90%). Nodifferences were observed in oviposition timing or daily egg collection counts. These results indicate that DE didnot compromise reproductive performance under these conditions, as total egg production remained comparableto that of the IE group. Similarly, adult emergence rates were unaffected by the delay, suggesting thattemporary low-temperature storage did not negatively impact pupal-to-adult survival. Under the testedconditions, storage at 17 °C and 70 % RH enabled a delay of up to 12 days while maintaining reproductivepotential. This approach represents a practical strategy for improving batch synchronization and operationalflexibility in industrial BSF production.