Diapause Induction, Color Changes, and Supercooling Point of Diapause Larvae of Yang (Hymenoptera: Eulophidae).

The chalcid wasp Yang (Hymenoptera: Eulophidae) is one of the dominant pupal parasitoids of (Drury) (Lepidoptera: Erebidae). In this study, the photoperiod's effect on diapause induction in using the alternative host was measured, revealing that is of the long-day type. The critical photoperiods for diapause induction in were estimated to be between photoperiods of 13:11 and 14:10 (L:D) h at 18 °C, and between photoperiods of 12:12 and 13:11 (L:D) h at 21 °C and 24 °C. We also found that diapausing larvae were grey-brown, while normally developed (non-diapausing) individuals were light yellow. The diapause-sensitive insect state was the larval stage, and the short light exposure treatment had a significant cumulative effect on diapause induction. The least squares method was used to calculate a lower developmental threshold of 13.34 ± 0.50 °C and an effective cumulative temperature of 184.46 ± 11.46 d·°C for post-diapause development. The average supercooling point of diapausing mature larvae was significantly lower than that of non-diapausing ones. Our research on provides a reference for the biological control of and other leaf-eating pests.