Archives of The Cold Blooded News

The Newsletter of the Colorado Herpetological Society

Volume 29, Number 3;   March, 2002

Ask the Vet

by Dr. Linda Randall

Mealworms are not truly worms, but are beetle larvae. There is only about a 24-hour period, right after molting, when they do not have a hard brown chitinous body covering. The day-old, soft, non-chitinous larvae are easier to chew and digest and therefore are a better source of energy than when they are covered with an exoskeleton. Some mealworms are also treated with a hormone that will prevent their metamorphosis into beetles. This will also cause them to grow into larger larvae.

The nutrition provided by mealworms (and this is true of all prey items fed) depends in large part on what is fed to them. According to Fredric Frye, DVM, the growing medium for mealworms should consist of wheat bran midlings supplemented with 15% alfalfa flakes, 20% high protein baby cereal and 15% dry poultry mash. Moisture is provided with freshly cut apples and potatoes. The ratio of calcium to phosphorus is out of balance in mealworms, and therefore the growing medium needs to have calcium added. In addition, herps fed a diet of insects and/or mealworms also need to have their calcium supplemented.

Wax worms are the larvae of the wax moth. They are soft worms, without the chitinous exoskeleton of the mealworms. Their culture requirements are more stringent than those of the mealworms and indudes honey, vitamin supplementation, infant cereal, calcium and brewer's yeast in particular portions. Recipes can be found in multiple sources. However, even without the hard exoskeleton, herps fed wax worms will also need supplementation, especially with calcium.

Neither worm should be the sole source of food for any animal. However, they are fine as part of a mixed insect diet. Both worms are safe.

I would also like to address the common misperception that mealworms can chew through the herp's stomach lining and kill the herp. This is totally unsubstantiated and should be placed in the "urban myth" category. However, it is a good idea to kill the worm first before force feeding it to a debilitated reptile, and, if it is at the chitin stage, grind it up so that the animal gets the most nutrition possible with the least expenditure of energy.