Influence of cold storage on survival and fitness of Mastrus ridens, an ectoparasitoid of codling moth

Abstract

The effects of cold storage on eclosion, longevity and fecundity of adults of Mastrus ridens, an ectoparasitoid of codling moth, were investigated by holding different life-stages (eggs, developing larvae, mature larvae, pre-pupae and pupae) at 4°C for different periods (4, 6, 8, 10 and 12 weeks). Cold storage of eggs for 4 weeks resulted in high larval mortality. The development periods after cold storage decreased and the immature mortality increased with advancing developmental stages before cold storage. The longevity of females decreased with increasing cold storage of pre-pupae and pupae. Neither fecundity nor oviposition period of females emerging from the seven selected treatments was different from the control (females reared at optimum temperature). Results indicated that 7-to 10-day-old M. ridens larvae can be stored for up to 12 weeks at 4°C without any detrimental effect on their survival or quality of adulthood. Application of this finding will help with supply of the large numbers of parasitoids needed during the release programme.