不同地区松突圆蚧耐寒性的研究

Cold tolerance of the pine armored scale Hemiberlesia pitysophila (Homoptera: Diaspididae) in different regions

  • 摘要: 为探讨松突圆蚧(Hemiberlesia pitysophila)对低温的地理适应能力, 2007年测定并比较了广东信宜和福建漳州、泉州和长乐4个地区冬季松突圆蚧雌成虫的过冷却点和信宜、泉州、长乐3地区各虫态的低温暴露死亡率。结果表明: 4个地区松突圆蚧雌成虫的过冷却点具有显著差异(P<0.05), 福建长乐的平均过冷却点最低, 为-15.71 ℃, 广东信宜的平均过冷却点最高, 为-13.68 ℃, 总体呈现随纬度升高而逐渐降低的趋势。在各种低温暴露下, 广东信宜松突圆蚧种群的死亡率均明显高于福建泉州和长乐种群; 尤其在-10 ℃时, 前者的死亡率达85.97%, 而后二者分别仅为37.58%和56.65%。松突圆蚧各地、各虫态的低温暴露死亡率变化规律均服从改进的双变量逻辑斯谛曲线模型(P<0.01), 但广东信宜各虫态和种群的致死中有效伤害低温累积(SLIT50)均明显高于福建泉州和长乐。因此认为: 随分布纬度上升, 松突圆蚧耐寒性存在逐步增强的趋势。

     

    Abstract: In order to explore geographic adaptability to low temperature of Hemiberlesia pitysophila (pine armored scale, a dangerous insect pest), its supercooling point (SCP, Xinyi in Guandong Province, and Zhangzhou, Quanzhou and Changle in Fujian Province) and exposure mortality (EM, Xinyi, Quanzhou and Changle) to a designated low temperature were measured in the winter of 2007. Results indicate that female adult SCP for the four regions is significantly different (P<0.05). It is lowest for Changle with a mean value of ?15.71 ℃, while is highest for Xinyi with a mean value of ?13.68 ℃. SCP exhibits a declining tendency with rising latitude. Under 10 ℃ to ?20 ℃, the mortality of the insect pest is remarkably higher in Xinyi than in Changle and Quanzhou. When specifically exposed to ?10 ℃, its mortality in Xinyi is 85.97%, but only 37.58% and 56.65% in Quanzhou and Changle respectively. Furthermore, the relationship between sum of temperature and population mortality in Xinyi, Quanzhou and Chanle is in accordance with revised double variable Logistic model. The same is the case for the five insect developmental stages including instar nymph (1st stage), instar nymph before sex differentiation (2nd stage), instar female (2nd stage), male nymph after sex differentiation and female adult. Median lethal sum of injury temperature (SLIT50) of the population is also higher in Xinyi than in Quanzhou and Changle. The findings imply that H. pitysophila is strongly adaptable to low temperatures with an increasing cold tolerance at higher latitudes.

     

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