How Is Climate Change Affecting Bugs?
Of the approximately 11 million species of plants and animals on Earth, about 5 million are insects. That compares with a paltry 5,500 species of mammal, 10,000 of bird, and 40,000 of fish. Throw in another 600,000 species of arachnids (spiders) and random worms and centipedes and you have a lot of bugs. And while they might not be as warm and fuzzy as polar bears, dozens of insect species are facing extinction. Just like polar bears, the threat to insects can be traced to disruptions in the environment caused by climate change.
Plant-dwelling insects represent about a quarter of all biodiversity found on Earth’s land surface. Many species have evolved in environments where specific temperatures allow them to thrive. When temperatures go above or below the average, there’s not much the insects can do about it. They become weakened and die. This not only harms the insects it also impacts plants they pollinate and animals that feed on them.
Climate change means warmer winters, earlier springs, and longer summers, all of which effect the reproductive cycles of insects. Warming is at least partially responsible for threatening 60 American insect species listed as endangered by the U.S. Fish and Wildlife Service. The list includes 17 beetles, 19 butterflies, 2 damselflies, 1 dragonfly, 1 grasshopper species, 2 moths, and numerous flies of different species. On a global scale, around 250 insect species are considered endangered.
And while scientists estimate that population growth rates of tropical insects will decrease by 20 percent in the coming years other insects are moving into regions they never inhabited. This means new pests are invaded places where they have no natural predators. These include forest-destroying insects such as the bark beetle, the green spruce aphid, and several types of weevil, all drawn to places where they were unable to overwinter in previous years.
Researchers warn that there are thousands of species that have yet to be discovered. While they may be unknown to scientists, many undoubtedly play an important role in their local environment. But one thing is for certain—the world’s biggest pests, like cockroaches and bedbugs remain completely unthreatened and will continue to plague humanity as long as the world spins around the sun.