Frankliniella occidentalis (Pergande) is an anthophilus pest of many greenhouse and field crops worldwide. We compared the influence of constant (27.3ºC) and fluctuating temperatures (23.8 to 31.5ºC, with an average of 27.3ºC) on the life table characteristics of F. occidentalis held at a 16:8 h L:D photoperiod and 45 ± 5% RH. The development times from egg to adult of F. occidentalis were significantly affected by temperature fluctuation and sex. Survival of immature life stages was higher under fluctuating than constant temperature. Total first instar larvae/female was not significantly different (58.7 at constant and 60.5 at fluctuating temperatures) but daily production of first instars was higher in constant temperature than fluctuating temperatures (3.3 at constant temperature and 3.1 at fluctuating temperatures). The off-spring sex ratio was not significantly different between constant and fluctuating temperatures. The intrinsic rate of natural increase (rm), net reproductive rate (R0), finite rate of increase (λ), mean generation time (tG), and doubling time (tD) were affected significantly by fluctuation of temperature. The intrinsic rate of natural increase of F. occidentalis was higher in constant temperature (0.1808) than did in fluctuation of temperatures (0.1733). Thus, this study show that variable temperatures influence population growth rates of F. occidentalis.

• Mohammad Shaef Ullah(Department of Bioresource Sciences, Andong National University, Department of Entomology, Bangladesh Agricultural University, Bangladesh)
• Un Taek Lim(Department of Bioresource Sciences, Andong National University)