To determine the cold effect to the Black soldier fly Hermetia illucens Two or three eggs mass, at the same age (within 24 hr.) will be mixed to prevent them belong to the same female; eggs, neonates, pre-pupa and adults (70 individuals of each stage) will be exposed at 10°C at a photoperiod of 12:12 (long day). For the diapause induction Two or three eggs mass, at the same age (within 24 hr) will be mixed; eggs, neonates, pre-pupa and adults: respectively will be exposed at 10°C at a photoperiod of 8:12 (short day) Insects will feed with artificial diet, longevity and survival rate will be daily recorded. First temperature to test will be 10°C if all insects died other temperatures as 15 and 20 °C will be tested.