Why are there insects? It's a question as old as the ages. Ogden Nash alluded to it in his poem "The Fly":
God in his wisdom made the fly, and then forgot to tell us why.
Nash is not alone. Almost everyone at one time or another has wondered why insects exist.
One important ecological service insects provide is nutrition for other animals. There are a lot of insect eaters out there. Some even have names that reflect their culinary habits.
Most people are aware of anteaters. These animals spend their entire lives dining on ants. And there's a bird called the flycatcher. It's name alone suggests its favorite food -- flying insects.
Many different animals use insects as a food source even if their names don't reflect it. Frogs and toads have sticky tongues to capture flying insects. Snakes and salamanders also will dine upon insects.
Many aquatic creatures feed upon insects as well. For that reason fishermen use artificial bait modeled after insects. These models are appropriately called flies. Fishing flies come in many shapes and colors, but you can bet they are designed to entice the fish into thinking it is about to eat a tasty insect.
Mammals also eat insects. Bears eat grubs that they dig out of rotten stumps. Skunks also eat insects. A grub-infested lawn is a great place for a skunk to dig up a meal. This process leaves holes in the lawn, much to the disgust of the homeowner. Even dogs and cats will chow down on an insect or two when given the chance.
Bats, the only flying mammals, depend upon insects for their entire food supply. Bats fly at night and use echolocation to navigate and catch night-flying insects, sort of a meal on the wing.
Many birds consume insects. Woodpeckers peck wood looking for larval insects. Wrens are great insect eaters. Many blackbirds also eat insects. A flock of blackbirds feeding on the lawn in the spring could be a sign of an insect infestation. That domestic fowl, the chicken, also delights in a good insect meal. Years ago chickens running in he orchard were considered beneficial because they ate the insects that were overwintering in the fallen fruit.
Why are there insects? They keep a lot of animals from going to bed hungry!