The Darkling Beetle, also known as the Mealworm in its larval state, is a fairly large beetle that is sometimes known as the "stink beetle" for the noxious odors they produce when threatened. They are often found in cupboards, pantries, or wherever food is stored.

"Mealworms" are commonly used to feed other animals and as bait for fishing. They are worm-like animals with a hardened body making them able to burrow. The egg of the Darkling Beetle is white, and the pupa is 1/2 to 3/4 inches long. The Darkling Beetle and the Mealworms both feed on decaying leaves, sticks, grasses and other plant matter. They also eat dead insects, feces, and grains. They live in regions such as woods or near areas where they can find their food under rocks, logs, in animal burrows or in grain stores. They are common anywhere that "leftovers" occur. They are eaten by rodents, lizards, spiders, birds and other beetles. Some of the beetles, those of the genus Eleodes, get quite defensive when disturbed. They stand on their head and release noxious chemicals from a scent gland at their rear. The chemicals have a horrible smell and can turn skin brown. Mealworms and Darkling Beetles are beneficial to the environment because they clean up organic waste materials. However, they can be pests to stored grain.

The Darkling Beetle is black with hardened front wings. They have many-segmented antennae that rise from a ridge near their eyes. Their head is visible from the top and is followed by a pronotum and elytra about the same width as the head. The mealworms are about an inch long and have a yellowish brown exoskeleton over their cylindrical body. The lifespan of the Darkling Beetle is about twelve months. During the larval stage, they may molt 9-20 times.

Mealworms are often used in school experiments. They can be purchased from pet stores and kept in an enclosure made of film cans. When handling the mealworms, use a plastic spoon or a folded piece of paper to scoop them up.

Mealworms should not be kept near sunlight. They should be fed any kind of cereal bran. They also enjoy fruits and vegetables such as apples, potatoes, or carrots. They should be kept fairly dry and temperatures between 40 and 80 degrees Fahrenheit.

Breeding Darkling Beetles is not difficult, though it is difficult to distinguish male and female beetles. A ten-gallon tank can be used with 1 to 2 inches of fresh oatmeal as substrate. Driftwood is needed for them to lay their eggs. Use 4 to 10 inch long, thick pieces of driftwood that is loaded with lots of holes and places they can wedge themselves into. Feeding them romaine lettuce, cucumber and red delicious or Macintosh apples will keep them healthy. Remove any uneaten food within a day or 2 to avoid fruit flies. Female beetles lay about 500 eggs at a time. In about 2 months you can sift through the oatmeal and find very tiny mealworms, which can stay there, since the adult beetles usually do not eat their larvae.