Invasive Species: Birds, Plants, Insects, Animals, and Mankind

On July 23, Maureen, over at A View from England, made an entry entitled “Grey Squirrels vs. Red Squirrels.” Using the BBC News as her source, she explained how “a massive cull of grey squirrels is to take place across England to try to halt declining numbers of the endangered native red population.”


To quote Maureen, “Yes, here in the U.K. we have red squirrels as well as the American grey squirrels. The grey squirrels were introduced to this country from America between 1876 and 1929, and they are thriving, while the red squirrel population is declining. Consequently, the grey squirrel is considered a huge pest in this country because of the damage to trees and woodland it has caused and by squeezing out red squirrels. The government's planned cull of the grey squirrels will be carried out by woodland and wildlife managers.”

This got me to thinking. More and more we hear about various species of birds, animals, plants and insects that were introduced from one country into another and eventually became pests in that new country, driving out the native species and overtaking their habitat. Also, the “newcomers” eventually changed from being the minority into the majority of dwellers in that habitat.

Starlings, as an example, were introduced into the U.S. from Europe, and because they thrived, are now considered a threat to our songbirds. On a different scale, look what happens when wildlife, such as deer, moves from the country into our suburbs’, and even cities’ back yards.

Also, consider what has happened with our native ladybugs, those shiny red insects with black spots (also called lady birds and lady beetles), that gardeners have coveted because the larvae and adults eat garden pests such as aphids, mealybugs and mites. The “Asian” ladybug was introduced to "naturally" destroy the tiny soybean aphids that were destroying soybean crops in the U.S. and Canada. Some accounts say that in the early 1980’s, the U.S. Department of Agriculture experimented with the insect in the southeast U.S., trying to establish it as a predator against aphids and other soft-bodied pests of pecan trees, a valuable nut crop. In 2000, the soybean aphid, an exotic aphid from China, was discovered feeding on soybean plants. In 2001, the multi-colored Asian lady beetle fed heavily on the soybean aphids and likely saved Michigan soybean farmers millions of dollars in harvest revenues and insecticides that didn't have to be used to control losses to this aphid species.

Yet these orange, imported ladybugs have thrived and proliferated to such an extent, they not only are driving out our more passive native species, but they have become invasive pests that pile up in our windowsills, and bite us and our pets.

So which is more important to us—the benefits we are reaping as a result of these foreign species—or our comfort?

Perhaps the most vivid example of a species being “introduced” into another nation or country is mankind. All around the world throughout history, we humans have overcome natives of the lands we’ve invaded, introduced foreign species into “our” lands, and made like species into slaves, yet in most cases we also accept those from other countries who want to move into our own, and many have thrived to create inventions and technology that has made our lives easier. And what would life be like if we in the U.S. hadn’t been able to come to America in the first place? I wonder, no matter whether it’s man, insect, plant or animal, does the bottom line somehow become a matter of control?