Mealworms are the larval form of the 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 2.5cm or more, whereas adults are generally between 1.25 and 1.8cm in length.

 

Mealworms can be easily raised on fresh oats or grain, with sliced potato or carrots and little pieces of apple as a water source.