Mealworms

Like crickets, mealworms (the larval stage of darkling beetles Tenebrio molitor) are arthropods and insects. Unlike crickets, mealworms undergo complete metamorphosis, meaning that the young do not resemble adults. Darkling beetles lay eggs (over 200 per female) which hatch into tiny larvae in 4 to 14 days. Mealworm is the name given to these larvae. The larvae molt five times, eventually turning into pupae. The pupae do not move much, but, after 3 weeks or so, develop into darkling beetles! The whole process, from egg to beetle, may take five or more months, depending on temperature (the warmer, the faster).

Mealworm Pupae Beetles

Few animals are easier to maintain than mealworms. All they need is a container and food (the beetles do not fly, so a cover is not necessary). A plastic food container or shoe box is adequate; the larger the space, the more offspring are made! Mealworms need ample amounts of dry grain (cereal, bran, chick-feed). They do not need water, but can extract it from bits of carrot or apple, and grow faster too! (As an added bonus, the mealworm makes orange frass or droppings when fed carrots, enabling the students to distinguish frass from eggs).

The mealworms and beetles prefer to burrow in the bran, so you will need to poke around if you want to see them. The beetles are much more active at night, so you may want to fool them and place them in a dark container to see them active. Plan on replenishing the culture medium every 2-3 months (keep some of the old one, since eggs are likely to be there!).

Mealworms and darkling beetles should not be released outside. If you are not planning on maintaining your culture indefinitely, consider giving them to a classroom or pet shop with toads, frogs, turtles, or salamanders, all of which will eat mealworms.