| Orthaga achatina Bulter (Lepidoptera: Pyralidae) is a significant defoliator of Cinnamomum camphora (Lauraceae). The mean temperatures during pupal development are obviously different between the overwintering and oversummering generations. Effects of different temperatures on the eclosion rate and enzymes related to glutathione metabolism were examined in Orthaga pupae.1 Effects of different temperatures on the eclosion rateWhen pupae of Orthaga achatina Bulter were transferred from 25℃to 16℃and 30℃, the eclosion rate decreased from 86% to 22% and 76%, respectively.2 Variations of glutathione and related enzymes in the 16℃-treated pupaeRatios of GSH and GSSG decreased from 1.01 to 0.87 in the 25℃-treated pupae and from 1.01 to 0.24 in the 16℃-treated pupae, respectively. It indicated that oxidative stress in pupae at 16℃is involved in the marked decline of eclosion rate. Compared with 25℃, the content of GSH decreased obviously,whereas the contents of GSSG and total glutathione increased. It showed that the stronger oxidation of glutathione in pupae at 16℃. Furthermore, the 16℃-treated pupae had higher activities of XOD, CAT, GST and TPX. It suggested that XOD enhancement in the 16℃-treated pupae leads to H2O2 accumulation, which reversely up-regulating CAT, GST and TPX.3 Variations of glutathione and related enzymes in the 30℃-treated pupaeRatio of GSH and GSSG decreased from 1.01 to 0.50 in the 30℃-treated pupae, which was intermediate between 25℃and 16℃. It indicated that oxidative stress in pupae at 30℃is involved in the marked decline of eclosion rate, whereas it was lower than that in pupae at 16℃. Variations of other biochemical parameters in the 30℃-treated pupae were similar to the 16℃-treated pupae.In conclusion, the marked decline of eclosion rate of Orthaga pupae at 16℃and 30℃is involved in pro-oxidative status, and also it was more serious in 16℃-treated pupae, which may be resulted from the stronger oxidation of glutathione catalyzed by GST and TPX. |
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