A Laboratory Study on the Modeling of Temperature-Dependent Development and Antioxidant System of Chilo suppressalis (Lepidoptera: Crambidae)

The developmental rates of Chilo suppressalis (Walker; Lepidoptera: Crambidae) were investigated at different constant temperatures of 11, 18, 22, 24, 26, 30, 32, 34, and 36 degrees C to find out temperature thresholds, thermal requirements and larval antioxidant responses. The time to complete immature stages separately reduced by raising the rearing temperature except for eggs which showed no significant differences at 30-34 degrees C. Data analysis by traditional and Ikemoto-Takai linear models determined Tmin of 10.0 and 9.92 degrees C as well as thermal constants of 840.34 and 848.0 DD for the overall immature stages. The models including Analytis, Briere-2, Lactin-2, and Sharpe-Schoolfield-Ikemoto (SSI) calculated Tmin values of 9.15, 9.57, 10.0, and 11.37 degrees C for overall immature stages while Tfast was found to be 33.8, 33.3, 33.7, and 33.0 degrees C, respectively. Tmax was calculated as 35.12, 34.66, 34.56, 36.84, 34.11, and 35.15 degrees C for Analytis, Briere-2, Lactin-2, SSI, Logan-6, and Logan-10. Topt using SSI was calculated as 24.42 degrees C for total developmental time. The larvae exposure to 34 degrees C in the short-term period demonstrated the highest activities of catalase, peroxidase, and superoxide dismutase compared to control (24 degrees C). Activities of ascorbate peroxidase and glucose-6-phosphate hydrogenase also increased at 34 degrees C in the short-term period for all preparations. The larvae exposed to 34 degrees C in short-term period showed the highest amounts of Malondialdehyde and oxidized and reduced thiols (RSSR/RSH) ratio compared to control. These results may be useful to explain potentially ecological performance of C. suppressalis as the major pest of rice in Iran.