Influence of Temperature on the Development, Growth Rate, and Life Table Parameters of Earias insulana Boisd. (Lepidoptera: Noctuidae) under Laboratory Conditions

              Experiments were performed at five constant temperatures of (12, 18, 23, 27, and 33 ± 2ºC) and relative humidity 65±5 % R.H. to estimate the threshold of development and thermal units’ requirements for laboratory strain of   Earias insulana Boisd. (Lepidoptera: Noctuidae) reared on an artificial diet without agar. Results of the total developmental period, percentages of adults’ emergence, and longevity of females are significantly affected when reared at different temperatures. The total developmental period of the immature stages was shorter at high temperatures than that reared at low temperatures. The incubation period of egg significantly affected by different temperatures which was 9.9 days at 12 ^oC but it was 2.4 days when eggs incubated at 33ºC, respectively. The lower threshold of embryonic development found to be 12.092^oC. The average thermal units expressed as degree-days required for completing the development of the incubation period for eggs was 49.31 DD’s. Also, tested temperatures significantly affected the larval duration and weight, the mean larval duration was 50.6 days at 12 ^oC but it was 10 days at 33 ºC. Also, mean larval weight affected with tested temperatures which were 0.00063 g at 12 ^oC, but it was 0.0017 g at 32 ºC. The lower threshold of development (T₀) for the larval stage was 10.97 ºC. The average thermal unite required for larval development till pupation was 215.1 DD̉̀s. Tested temperatures significantly affect on the pupal duration, the meanpupal duration was26.3 days at 12 ^oC, but it was 5.5 days at 33 ºC. Also, mean pupal weight affected by tested temperatures, which were 0.0005 and 0.0014 g at 12 ^oC, and 33 ºC, respectively. The developmental threshold (T₀) for the pupal stage was 12.7044 ºC and the average of thermal heat units for pupal stage was 110.063. The highest adult emergence percentage was occurred at 27^oC, which being 92%; also pre oviposition period, significantly affected by temperature, which were 4.9 and 24, 27 days at 18 ^oC and 33 ºC, respectively. The threshold development (T0) of pre- oviposition preiod was 14.13 ºC, while, the average degree days (DD̉s) required for complete development to lay the first egg was 33.94 DD̉s. Generation time also, significantly affected by tested temperatures, whichwere 57.1 and 19.3 days at 18 ^oC and 33 ºC , respectively , the developmental threshold (T0) for generation of E. insulana was 11.15°C, while, the average degree days (DD̉s) required for complete generation was 413.4 DD̉s when fed on previous artificial diet. Also ovi-position, post ovipositoin and longevity of adult were significantly affected. Results of the life tables for E.insulana showed shortage in generation periods for that reared at high temperatures and vice versa occurred at low temperatures. The present study was conducted to explore the effect of different temperature on some biological parameters of E.insulana.