Cool storage of Queensland fruit fly eggs for increased flexibility in rearing programs

BACKGROUND: The Queensland fruit fly (Q-fly) is Australia's most economically damaging insect pest of fruit crops. The Sterile Insect Technique (SIT) used to suppress outbreaks relies on supply of high-quality flies and this can be assisted by the ability to manipulate production schedules. Cool storage at temperatures that are sufficient to slow development without causing significant somatic damage can provide a valuable means of manipulating production schedules. In this study, we investigate the effect of four storage temperatures (10, 13, 16 and 19 °C) and three exposure times (3, 6 or 9 days) on Q-fly eggs. RESULTS: Egg storage proved effective in prolonging the developmental time of Q-flies. Storage at 10 °C was unsuitable, resulting in a low hatching rate for all exposure times. Hatching rate was also significantly reduced when eggs were exposed to 13 °C for 6 or 9 days, followed by a significant reduction in the number of pupae recovered. Storage at 16 °C yielded promising results, prolonging the preimaginal development of Q-flies up to 6.5 days without significantly affecting egg hatching or subsequent development. CONCLUSION: Cool storage of eggs shows promise as a tool for prolonging the development of Q-flies to manipulate schedules in mass rearing programs.