Insects are small, six-legged animals that don't have an internal skeleton. They are the most successful animal group on Earth. Of all the named animal species, about one million are insects. West Virginia is estimated to have 20,000 or more species.

West Virginia's mountains create many different environments where insects can live. Because parts of the high-altitude mountains are very cold (like a boreal forest), they are home to insects usually found much farther north, such as the Atlantis fritillary butterfly in places like Dolly Sods.

Less than 1% of insects are harmful, but they can cause big problems. Some spread diseases (like mosquitoes). Many are pests that destroy crops and trees, such as the native eastern tent caterpillar and the introduced gypsy moth. The state spends time and money trying to control damaging invasive species.

On the other hand, insects are crucial to the ecosystem. They are a major food sources for birds, fish, and other animals. (Fishermen use "flies" that look like insects as fish bait.) They are necessary for pollinating many crops. The honeybee is so important it was named the official state insect in 2002.