水流对莲草直胸跳甲种群存活和扩散的影响

【背景】水流是外来入侵生物传播蔓延的重要方式之一,特别是水生生物。水生杂草在水流传播过程中也经常携带其天敌从一个地方传播到另一个地方,如莲草直胸跳甲经常随着空心莲子草在水流中传播。研究水流对莲草直胸跳甲存活的影响及其对种群迁移的间接协助作用,可为解析该天敌抵御洪涝灾害和借助水流传播的能力提供科学依据。【方法】本研究以莲草直胸跳甲为研究对象,在室内进行水流模拟,比较水流转速（1000、1250和1750r.min-1）和时间（30、60、90和120min）对不同虫态莲草直胸跳甲（雌雄成虫、幼虫和卵）存活率的影响,并推算莲草直胸跳甲成虫和幼虫在野外随水流传播的最大距离。【结果】水流速度对昆虫的存活和发育具有一定影响。在不同旋转时间和转速下,雌雄成虫的存活率较高,幼虫次之,卵的存活率最低;雌虫随水流传播能达到的最远距离最大,雄虫次之,传播距离最小的是幼虫。【结论与意义】莲草直胸跳甲可随水流进行远距离传播和自然扩散,对于利用莲草直胸跳甲防治空心莲子草,缓解水渠和河道的堵塞非常有利。

Effects of water flow on the survival and dispersal of the flea beetle,Agasicles hygrophila

[Background]The water flow is one of the important spathways of spread for invasive species,especially aquatic ones.This can also aid the dispersal of introduced natural enemies,such as Agasicles hygrophila,a biological control agent and alligator weed Alternanthera philoxeroides.Knowledge of the effects of water flow on A.hygrophila and indirect effects of water flow on population relocation would provide scientific basis for more effectively spread natural enemies via this route.[Method]Artificial water flow was used to compare the impacts of stream speed on the survival rate and dispersal distance of A.hygrophila at different developmental stages.[Result]Water flow can affect the survival and development of insects.Among the tested stages,female and male adults had the highest survival rates,larvae ranked the second.Eggs were intolerant of water flow at the speeds of 1000～1750 r·min-1.A.hygrophila females spread the farthest,followed by males,and larvae spread the shortest.[Conclusion and significance]A.hygrophila could disperse long distances under water flow and can use water flow as a natural dispersal pathway.This is good for control alligator weed by flea beetle in order to release jam of penstock and river way.