Cool storage of Queensland fruit fly pupae for improved management of mass production schedules

BACKGROUNDCool storage is a valuable means of manipulating insect development time. The Queensland fruit fly (Q-fly) is Australia's most economically significant pest of fruit crops. The present study investigates cool storage of Q-fly pupae for increasing production flexibility for sterile insect technique programs. Development time, survival and fly quality were assessed following continuous storage of 1-day-old pupae at temperatures ranging from 13 to 25 degrees C. RESULTSSurvival was reduced almost to zero by pupal storage at 13 and 15 degrees C, was greatly reduced by storage at 17 degrees C, and was modestly reduced by storage at 19 degrees C. Pupal development time was extended by 16days at 17 degrees C and by 9days at 19 degrees C. Cool storage negatively affected flight ability and depleted lipid reserves. Cool storage at 19 degrees C enhanced the ability of 3-day-old adults to recover from chill-coma compared to control flies, indicating cold acclimation. CONCLUSIONThere is potential for use of cool storage in Q-fly mass rearing, especially to improve alignment between production and field releases. For the purpose of delaying the development time of Q-fly pupae with minimal quality reduction, storage at 23 degrees C is recommended for 1-day-old pupae. (c) 2019 Society of Chemical Industry