Surely you will not be surprised to find one or two beetles that you have never seen before on the grass near the roadside or in your yard. However, it may not be a usual thing from the perspective of biologists and ecologists. The expression of “biological invaders” is used by experts to refer to these “immigrants” that used to live abroad and then migrated into a new ecological environment by unnatural means. The invaders will not only destroy the original ecosystem of a certain region, but also probably cause the human society a financial loss that is difficult to measure.