Adaptation Of Turpan Bemisia Tabaci (Gennadius) B-biotype To Thermal Stress

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), distributes widely in over 90 countries and regions in tropical, subtropical and temperate areas. Damages of B. tabaci to host plants include direct feed on plant phloem sap, transmit plant viruses, and cause physiological disorder of plants. After the introduction of B. tabaci B-biotype into China in 1990s, it has spread rapidly and broken out in many provinces, causing severe economic lost in agriculture.Many former studies show that the adaptability of B. tabaci B-biotype to high temperature stress is one of the key mechanisms of its successful invasion and expansion throughout the world. This stdudy aims to: (1) compare The longevity, fecundity, sex ratio, the survival rates of eggs, red-eyed nymphs and adults of B. tabaci B-biotype under high temperatures, (2) compares the differences of thermal stress tolerance between Turpan B. tabaci B-biotype and Beijing B. tabaci B-biotype. The main results are as follows:1. In both whitefly, the decreased survival due to the brief exposure of high temperature represented significant difference between female and male adults and females appeared higher survival than that of males. In addition, Turpan B. tabaci B-Biotype female adults had higher survival than that of Turpan B. tabaci B-Biotype at the same conditions. The similar phenomenon was also observed in male adults of two whitefly .2. The female fecundities were not significantly different when B. tabaci biotype B adults were exposed to all temperatures. Survivals rates of the F1 nymphs of both whitefly declined as the increase of temperature, and The survival rate of F1 progeny of Beijing whiteflies was significantly lower than that of Turpan whiteflies from 39 to 45. Sex ratios of the F1 offspring were were slightly affected for B. tabaci biotype B at the heat shock temperatures 43 and 45°C. but There were no significant differences between sex ratio of Beijing whiteflies and that of Turpan whiteflies.3. The survivals of three developmental stages of two whitefly species decreased with the increase of temperature and the prolonging of heating period. Further, the survival rates of eggs, red-eyed nymphs and adults of Beijing B. tabaci B-biotype were higher than those of Turpan B. tabaci B-biotype. There were significant differences when heat tolerance between these two whitefly was compared. At 43℃for 4~6h and 45℃,the survival rates of eggs Turpan B. tabaci was significantly higher than that of Beijing B. tabaci; At 41℃for 4~6h, 43℃, 45℃, the survival rates of red-eyed nymphs of Turpan B. tabaci was significantly higher than that of Beijing B. tabaci ;at 43℃for 2-6h and 45℃, the survival rates of adults of Turpan B. tabaci was significantly higher than that of Beijing B. tabaci, and the adult had the weakest tolerant ability to extremely high temperature 43 and 45℃.