Collection of host insect wax moth (Galleria mellonella) The target host used in the study was Galleria mellonella (L.) (Lepidoptera: Pyralidae). It was originally collected from infested bee-hive and maintained on artificial diet in IPM laboratory, Entomology Division, Bangladesh Agricultural Research Institute, Gazipur, Bangladesh. The dark bee wax was sterilized by boiling and put in 1000 ml glass jars. One hundred larvae of wax moth were kept in the glass jar. The adults of G. mallonella coming out from the wax in the jar were allowed to mate and egg laying. After egg hatching, the 1st and 2nd instar larvae of wax moth were released in jars containing artificial diet. The diet was prepared by mixing wheat flour, maize crush, milk, sugar, animal fat, wax and yeast and autoclaved at 120 oC under 1.0 Kg cm-2 pressure for 70 minutes. Full grown final instar larvae were collected after 18 to 20 days and used as host for rearing of B. hebetor. The ambient temperature of the rearing room was 26.0 ± 2oC, relative humidity 70 ± 5 % and 12L: 12D photoperiod. Collection of Bracon hebetor Bracon hebetor was obtained from IPM laboratory, Entomology Division, BARI, Gazipur. It is used for many years for the biocontrol of lepidopteran pest and maintained on honey and last instar larvae of G. mellonella. Adult parasitoids were introduced into plastic jars (1000 ml) containing last instar larvae of G. mellonella and a cotton ball soaked with honey. Mouth of the jar was covered with black cloth. Environmental conditions of the rearing were the same as used for rearing the host G. mellonella. To obtain newly emerged parasitoids, 3 females and 2 males of B. hebetor adults were released into a plastic jar containing 10 G. mellonella final instars larvae and the whole container was covered with black cloth and kept for 3-4 days. To assess the parasitic activity of the B. hebetor in low temperature, 3 to 4 days old parasitoid pupae were isolated from the laboratory culture and placed in plastic jars. Before placing of pupae, the jars were sterilized in an electric oven. Each jar received 50 parasitoid pupae. The jars were stored in a refrigerator at 4±1°C and 60-70% RH for 1, 2, 3, 4, 5, 6, 7 and 8 weeks. Four jars (replications) were used for each treatment (storage period). Another four jars containing pupae of the parasitoid were stored at room temperature, which served as a control. Effect of cold storage on Bracon hebetor parental generation At the end of each storage period, the pupae were moved to a chamber having ambient temperature of 26±2 oC and RH 70±5%. Data on pupal survivability (adults emerged per parasitized pupae), time of adult emergence (days between the end of cold storage of the pupae until emergence of adult parasitoid) and sex ratio (adult females per total individuals) were recorded. The effects of storage time in low temperature storage on parasitism, longevity and fecundity of the parental generation were noted. To examine the capability and performance of a female B. hebetor after low temperature storage, a female and a male were taken where emerged from each cold storage period. Both male and were placed in a plastic jar (1000 ml) having corrugated sheet containing 10 released larvae of G. mellonella and a cotton ball dipped in honey. The mouth of the jars was covered with black cloth and the whole container was covered with black cloth. The wax moth larvae and B. hebetor were placed on a rack for 8-10 days for parasitization, egg laying, pupation and adult emergence of B. hebetor. Data were expressed as % parasitism, fecundity and total adult progeny and sex ratio for each storage duration. Each treatment was replicated four times using completely randomized Design. There was also a control treatment maintaining room temperature 26±2 oC and 70±5% RH.Statistical analysis Data were analyzed using SPSS 16 software and presented in mean ± SE. Mean time of developmental, parasitism, longevity of adult, sex ratio, and daily and lifetime fecundity of the parasitoid were evaluated using one-way Analysis of Variance (ANOVA). Differences among the means were evaluated using Turkey’s Honestly significant differences test. Before performing ANOVA, % parasitism, survival and mortality were transformed using arcsine transformation.