Mealworms are the larval form of the yellow mealworm beetle, Tenebrio molitor, a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult. Larvae typically measure about 2.5 centimetres (0.98 in) or more, whereas adults are generally 1.25 to 1.8 centimetres (0.49 to 0.71 in) in length.
Mealworms are great feeder insects for reptiles, birds, aquariums, monkeys, pigs and poultry.
They are recognized as a staple feed for many pet owners across the globe.