You must determine the type of beetle first before asking the question, “What do beetles eat?” There are over 350,000 species of beetles, they make up for 40% of insect population and 25% of all life forms on the planet. Besides for polar regions or the sea, they are found in every other part of the world.
Food And Eco-System
Beetles have an interaction with Eco-systems in many different ways. Many will feed on fungi and plants and break down plant and animal debris as well as eat invertebrates. Some are agricultural pests while others are important in controlling other pests such as scale insects, aphids and thrips that damage crops.
Beetle species that feed on plants help to control weed problems and Dung beetles reduce parasite worms and flies that breed in cattle dung. There are some farmers that actually develop a beetle bank to provide a safe cover for species of beneficial beetles to dwell.
They eat a diverse food selection depending on the species. Some are omnivores, feeding on animals and plants while others require a specialized diet. Longhorn beetles, Leaf beetles and Weevils will only feed on a specific plant for their whole entire life. Rove beetles and Ground beetles are carnivores primarily and will attack and eat arthropods, snails and earthworms. Most beetles are considered generalists but there are some that have high requirements of specific prey.
Many beetles love to feed on organic matter that is decaying including dead animals and dung. Domestic beetles will eat fruit, cereals, grain, nuts and flour while the Waste Grain beetle makes a diet out of decaying vegetation. Larder beetles attack nests of rodents and birds, carcasses or dry animal hides and Carpet beetles will eat fur, carpet, textiles, flowers and pollen and are considered highly destructive. So, what do beetles eat? Pretty much anything.
Although appendages and organs can vary slightly from species to species, the anatomy of the beetle is fairly uniform. The body is divided by sections including the head, abdomen and thorax. All three sets of legs and the wings arise from the thorax. Everything that is posterior to this is the abdomen.
If you view a beetle from above, it may look like it has three clear sections however, this is quite deceptive. The middle part on the upper section is the pronotum which is a hard plate, the back part is covered by wings and you can't actually see it. Each segment of their body are then composed of several other segments.
The beetle’s hard fore-wings are called elytra and the insect is characterized by their extremely hard exoskeleton. This exoskeleton has numerous plates that are also separated by sutures. This design allows the beetle to maintain flexibility while having an armored defense.
Some beetles do not have the ability to fly such as ground, cave-dwelling and desert species. They have a mouth like a grasshopper that looks like pincers, called mandibles. These mandibles are tooth-like, hard structures that are used to crush, grasp and cut food. Around the mouth are finger-like appendages used to move the food to their mouth.
Beetles' antennae are used mainly for smell and to feel out the surrounding environment. The legs are multi-segmented and although they use them to walk, some species use them for swimming, digging or jumping.
Their tracheal system obtains oxygen and pumping movements within the body distribute it through their system.
Beetles are complex little creatures, making up the largest family in the animal kingdom. They have both positive and negative points to them and one species or another will eat just about any edible thing on the planet.