Temperature-Dependent Demography of Thrips hawaiiensis (Thysanoptera:Thripidae): Implications for Prevention and Control

The Hawaiian flower thrips, Thrips hawaiiensis (Morgan), a common flower-inhabiting thrip, is now a potential pest globally. Effective control of T. hawaiiensis requires information about the effects of temperature on its ontogeny and population growth. In this study, the life history characteristics and demography of T. hawaiiensis were defined at eight temperatures (9-35 degrees C). Additionally, the thermal constant and temperature threshold were estimated by regression analysis. The developmental duration and longevity of T. hawaiiensis decreased with an increase in temperature between 16 degrees C and 32 degrees C; females survived for longer than males at all temperatures. The lower temperature threshold and thermal constant of preadult T. hawaiiensis were 10.5 degrees C and 132.5 degree-days, respectively. The oviposition days of the females gradually decreased from 16 degrees C to 32 degrees C, and net maternity was higher at 20 degrees C than at 16 degrees C, even though the same number of eggs were laid at both temperatures. The mean longevities of the populations were greatest at 20 degrees C; the life expectancy and reproductive value decreased with temperature. The intrinsic rate of increase and finite rate of increase were significantly highest at 20 degrees C, 25 degrees C, and 30 degrees C. Population growth was triggered at 12.3 degrees C, and reached a peak at approximately 27 degrees C when it proliferated to the largest population size. Therefore, the results suggest that although the population of T. hawaiiensis starts to grow at lower temperatures, it adapts to a wide range of temperatures, and these findings facilitate prediction of different stages of damage, population size, and seasonal occurrence of T. hawaiiensis.