水浸对红火蚁工蚁死亡率的影响

Effect of water immersion on worker mortality in the imported fire ant,Solenopsis invicta

洪水会使陆生生物,尤其是土栖昆虫,陷入缺氧的困境。红火蚁Solenopsis invicta Buren一般将蚁巢建在潮湿的地方,使得蚁巢有很大的可能性被洪水冲袭。本文研究了浸水时间以及温度对红火蚁工蚁死亡的影响,包括小型工蚁和大型工蚁在25℃恒定温度下的耐浸水能力以及温度变化对小型工蚁死亡率的影响。结果表明:(1)浸水时间对于红火蚁工蚁的死亡率影响较大。浸水时间越长,工蚁死亡率越高。大型工蚁和小型工蚁对浸水的耐受性存在差异,大型工蚁比小型工蚁具有更强的耐浸水能力。浸水时间(T)和工蚁死亡率(M)关系符合以下模型:小型工蚁M minor=-25.01+4.49T;大型工蚁M m ajor=-26.9+3.96T。(2)温度对于小型工蚁的浸水死亡率影响明显。浸水10 h,小型工蚁死亡率(Y)和温度(X)为开口向上的抛物线关系:Y=115.2-11.88X+0.33X2。在温度X=18.21℃,方程具最小值,死亡率Y=7.04%。

Flooding could put terrestrial organisms, especially soil insects, in hypoxia conditions. The red imported fire ants, Solenopsis invicta Buren always build their nests in humid areas, which makes them being immersed by flooding at a high risk. We studied the effects of immersion time and temperature on workers of the imported fire ant in the laboratory. The workers mortality was influenced significantly by the time that the workers were immersed in water. The longer the immersion time was, the higher the workers mortality would be. The relationship between the immersion time （T） and mortality （M） is in accordance with the following model： Mminor = -25.01 ＋ 4.49T for minor workers; Mmajor = -26.9 ＋ 3.96T for major workers. And the major workers have stronger immersion tolerance than the minor workers. Temperature also plays an important role in the minor workers mortality after immersion. The minor workers mortality after 10 h immersion was obtained at seven different temperatures （5, 10, 15, 20, 25, 30 and 35 ℃）. And the correlation of mortality and temperature of the minor workers matches the mathematical second order polynomial regression model ： Y = 115.2 - 11.88 X ＋ 0.33 X2. And when X = 18.21 ℃, the equation has the minimum value Y = 7.04%.