粘虫生物学特性及生命表研究

以万源县第二代粘虫为研究对象,依据颜色变化将卵分为4级;依据复眼色泽、体色和翅芽变化将蛹分为5级.确定了头宽值的幼虫分龄标准,并认为粪粒大小和体长也可作为分龄的参考标准.建立了卵块大小(X)与含卵量(Y)的关系Y=20.38+4.261 4X.讨论了各虫态的习性、历期及发育进度等生物学特性.建立了实验种群特定年龄生命表.世代死亡率为82%,卵、幼虫、蛹和成虫期的死亡率分别为8%,55.54%,19.75和50.61%.种群增长指数I=0.423 7,分析了种群数量减少的原因.     

The responses of East Asian Summer monsoon to the North Atlantic Meridional Overturning Circulation in an enhanced freshwater input simulation

We investigated the response of the East Asian Summer Monsoon （EASM） to a weakened Atlantic Meridional Overturning Circulation （AMOC） and its mechanism in an enhanced freshwater input experiment （FW） by using a fully-coupled climate model. The response was a weakened EASM and the mechanisms can be explained as follows. The simulated weakened AMOC resulted in a drop in sea surface temperature （SST） in the North Atlantic （NA） and, correspondingly, an anomalous high sea level pressure （SLP） over the North American regions, which in turn increased the northeast surface winds across the equator in the eastern tropical Pacific （ETP）. The anomalous northeast winds then induced further upwelling in the ETP and stronger air/sea heat exchange, therefore leading to an anomalous cooling of the eastern tropical sea surface. As a result, the climatologic Hadley Circulation （HC） was weakened due to an anomalous stronger sinking of air in the ETP north of the equator, whereas the Walker Circulation （WC） in the western tropical Pacific （WTP） north of the equator was strengthened with an eastward-shifted upwelling branch. This feature was in agreement with the anomalous convergent winds in the WTP, and led to a weakened EASM and less East Asian summer precipitation （EASP）. Furthermore, comparison with previous freshwater experiments indicates that the strength of EASP could be influenced by the magnitude of the added freshwater.