最先出现的是矢车菊。然后是瘿蚊。现在,老鼠又泛滥成灾——它们身上携带有汉滩川病毒。这是人们在无意之中造成一系列生态后果的典型案例:本为控制一种多余的植物,结果却使一种危害人类的疾病愈演愈烈。斑点矢车菊是原产欧洲的一种形状细长、生命力顽强的植物。它们在美国西部的山坡和丘陵疯狂蔓延。蒙大拿是受害最大的州之一。光是在这一个州,斑点矢车菊就覆盖了400多万英亩的土地。20世纪70年代,生物学家引入了矢车菊的一种天敌:瘿蚊。这种昆 The first to appear is cornflowers. Then it is a mosquito. Now, rats are flooding again and again - they carry Hantanchuan virus. This is a typical case where people unintentionally caused a series of ecological consequences: it was the control of an unwanted plant, but the result was a growing disease that harmed humans. Spotted cornflowers are a long-stemmed, life-threatening plant native to Europe. They spread wildly on hills and hills in the western United States. Montana is one of the worst affected states. In this state alone, spotted cornflowers cover more than 4 million acres of land. In the 1970s, biologists introduced a natural enemy of bluebonnets: ticks. This kind of Kun