Multiple generation effects of high temperature on the development and fecundity of Bemisia tabaci （Gennadius） （Hemiptera Aleyrodidae） biotype B

Insects are ectotherms and their ability to resist temperature stress is limited. The immediate effects of sub-lethal heat stress on insects are well documented, but longer- term effects of such stresses are rarely reported. In this study, survival, development and reproduction of the whitefly, Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） biotype B, were compared over five consecutive generations at 27, 31 and 35℃ and for one generation at 37 ℃. Both temperature and generation significantly affected the fitness of the whitefly. These impacts were more dramatic with increasing generations and temperatures. Among the experimental temperatures, the most favorable for development and reproduction were 27 ℃ and 31 ℃. At 27 ℃, survival, development and fecundity were all stable over these five generations. At 31 ℃, immature survival rate was the highest in the fifth generation, but female fecundities decreased in the fourth and fifth generations. At 35 ℃, egg hatching rate, immature survival rate and female fecundity decreased significantly in the fourth and fifth generations. At 37 ℃, survival ofB. tabaci was not adversely affected, but female fecundity at 37 ℃ was less than 10% of that at 27 ℃ or 31 ℃. These results demonstrate that the lethal high temperature for B. tabaci is over 37 ℃, and the whitefly population continued expanding in the five generations at 35 ℃. The ability orB. tabaci biotype B to survive high temperature stress will play an important role in its population extension under global warming.