By Chris Williams on December 9, 2011.
Everyone likes beetles. Kids are always collecting and playing with beetles. Did you know that lightning bugs, also called fire flies, are neither bugs nor flies, but are actually beetles? Beetles aren’t usually scary and we don’t worry about them biting or stinging us, so beetles are kind of fun and very interesting.
Beetles belong to the insect order Coleoptera, which is the largest group of insects. There are more beetles than any other kind of insect with more than 350,000 beetle species in the world. The beetle group contains both the smallest and the largest of all the insects. Hairy winged beetles are barely 1/100th of an inch long and can easily crawl through the eye of a needle. The Goliath beetles in Africa are the largest insects at almost 5 inches long. Their large larvae weigh about 3.5 ounces and are eaten as food in many countries. Beetles are the strongest of all insects. Some beetles can lift 800 times their own body weight.
Beetles live in all kinds of habitats: in water, in wood, on plants, even in animal nests. They have chewing mouthparts in both the larval and adult stages but it’s usually the larvae that do most of the feeding damage. Many beetles feed on plants, including crops. Others feed on fungi, stored food products like grain, or on wood.
Because there are so many different beetles, you can imagine that there are lots of different beetle specialists. Some beetles, like the predaceous diving beetle, are aquatic and can survive for long periods underwater using an air chamber under their wings. Bombardier beetles eject poisonous gas from their rear end with a loud “pop” sound to discourage predators. Rove and carrion beetles help clean up the environment by feeding on and burying dead animals. Dung beetles help too by rolling animal poop into balls and burying them. Lady beetles are beneficial predators on other insects. Many beetles are destructive though. Tiny powderpost beetle larvae can do a great deal of damage to wooden structures. Some beetles, like carpet beetles, can damage furs, hides, and fabrics. Flour beetles and others that feed on stored foods contaminate more food with feces and shed skins than they actually eat.
Beetles all have what entomologists call “complete metamorphosis.” This means that they go through a larval and a pupal stage before they turn into adult beetles. The larva is wormlike and looks completely different than the adult beetle it will become. For example, those big C-shaped grubs that you sometimes find in the soil in your yard and garden will pupate and turn into the brown May or June beetles that end up bumbling around on your front porch. Hard to believe that the two are actually the same insect!
We don’t think of beetles as having wings at all, yet most have two pair. The front wings are adapted to serve as hardened wing covers that meet down the middle of the beetle’s back. Under the protective wing covers is the folded second pair of membranous wings. When a beetle flies, the wing covers spread apart at the center and the flight wings underneath unfold. You usually don’t see this, it happens so fast. Many beetles can fly, although most rarely do. But if you’ve ever tried to pick Japanese beetles off of your flowering plants, you know that they can fly.