Abstract: By using life table parameters, the effects of seven constant temperature regimes (17, 20, 23, 26, 29, 32 and 35 ℃) on the development and reproduction of Sylepta derogata was investigated. The results indicated that the durations of egglaying, larval, pupal, and adult stages of S. derogata shortened significantly when the temperature increased from 17 ℃ to 26 ℃, but prolonged at 32 ℃ and 35 ℃. The lower development threshold temperature of S. derogata at its all development stages was 12.08 ℃, and the effective accumulative temperature was 436.2 degreedays. The survival rates of all immature stages were the highest at 26 ℃, and would be decreased when the temperature was above or under 26 ℃. The innate capacity to increase (r_m), net reproductive rate (R₀), and finite rate of increase (λ) reached the maximum at 29, 26 and 32 ℃, with the values being 0.1268, 415.65 and 1.185, respectively. The mean generation time (T) shortened with increasing temperature, with the maximum and minimum values of 89.11 and 28.68 days at 17 ℃ and 35 ℃, respectively.

Key words: Tibet, Rhododendron aganniphum var. schizopeplum, timberline, population distribution.