Temperature and refrigeration time of Anticarsia gemmatalis (Lepidoptera: Noctuidae) pupae affect biological parameters of Trichospilus diatraeae (Hymenoptera: Eulophidae)?

Abstract

Development of parasitoids in hosts kept at low temperatures, without loss of quality, is important for mass rearing. Accordingly, reproduction of Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) was evaluated on Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) pupae after being stored at 0oC or 5°C. In experiment 1, A. gemmatalis pupae with up to 24 hours of age, were stored at 0oC, 5oC or 25°C (control) for one, three, six, nine or 12 days and exposed to parasitism for 10 females of T. diatraeae for 24 hours. In experiment 2, A. gemmatalis pupae, with up to 24 hours of age were exposed to parasitism by 10 females of T. diatraeae for 24 hours and after they were kept at 25°C until the parasitoid reached pupae stage, when they were stored at 0oC, 5oC or 25°C (control) for one, three, six, nine or 12 days. In experiment 1, parasitism of T. diatraeae on stored pupae of A. gemmatalis was greater than 90%, except at 25°C for 12 days. Emergency, progeny and longevity of males and females descendants form F1 generation were reduced with storage (0oC or 5oC). In experiment 2, storage of parasitoids at 5oC for one day increased emergency, not influenced the life cycle period with progeny similar to the control treatment. Sex ratio and width of cephalic capsule of males and females of T. diatraeae were similar to the control treatment in the experiments. Cold storage (0oC or 5oC) of unparasitized A. gemmatalis pupae or with immature stage (pupae) of parasitoid in it, for more than one day, negatively affects reproduction of T. diatraeae.