Lots said about mealworms. Some say they're the Devil--that offering them is death. There are urban myths about how they chew through the body wall of lizards that have swallowed them, or that their exoskeletons are hard to digest, or that they offer little food value.

Not exactly.

Since lizards chew and kill their insect food, mealworms arrive in a lizard's stomach in pretty poor condition to be chewing through body walls. I've had mealworms eat lizards they found dead before I did but as for the Last Act Of Defiance...chewing through the body of a predator seems unlikely.

As far as hard to digest, plenty of the herps we all keep eat things like ants, at least opportunistically. Compared to ants, mealworms are the soft-boiled eggs of a reptile's diet. Anything that eats ants or beetles can digest mealworms....with reservations, which are important.

Mealworms are in the beetle Family Tenebrionidae, which includes the Desert Darkling Beetles, familiar to residents of Texas, southern New Mexico and Arizona's deserts. Desert Tenebrionids defend themselves with noxious sprays of toxic fluids. Part of their foul-smelling cocktail includes chemicals called cyanoquinones. Insects use quinones in the metabolic process of hardening their shells after molting. Quinones are also used in tanning leather and a few beetles that spray quinones in defense can tan small spots on a person's skin where the spray landed. Quinones are bad enough--adding cyanide is just icing the cake, as it were.

As members of the Tenebrionidae ("ae" is pronounced "ee" in Latin names), Mealwoms sequester cyanoquinones in their shells as they harden and color up after molting. I find that while my Horned Lizards will eat mealworms, they may throw up hardened ones but will digest freshly molted, white ones with no trouble. They are strongly attracted to white mealworms and I offer white mealworms several times a week. Lizards with compromised digestion, such as animals stressed by shipping might have trouble digesting fully cured mealworms.

As to nutrition, mealworms are mostly guilty as charged, again with important exceptions.

Store-bought mealworms are some of the worst reptile foods I ever saw. Raised on the cheapest horse oat flakes (a treat for horses flavor-wise but not a dietary staple), store-bought mealworms are not only nutritionally empty, after the stress of shipping they're mostly dead. About as useful as pencil leads and about as appetizing.

Solution? I raise my own mealworms and have for years. I feed them ground gamebird crumbles for laying hens, marketed as a product called Layena. It's the same stuff the better cricket ranches feed their crickets. I grind the Layena crumbles in a blender to turn them to dust so it's easier to separate the mealworms from the bedding by sifting them through a pasta spoon with holes in it. Raised on good diet with steady watering (a square of Handi-Wipe fabric placed on top of the food and moistened daily), and mealworms are not only good eating, there are always freshly molted ones available for things like Horned Lizards.

I also slip my mealworms some Dandelion leaves at intervals during their growth. This puts extra Beta-Carotene into the mealworms as they grow. Beta-Carotene is valuable for reptiles, improving immune function and enhancing color. Just to be sure, I put some mealworms in a cup with chopped Dandelion leaves for a day before feeding them to herps which are scheduled to receive extra Beta-Carotene that week.

I've raised anoles through several generations on diets of almost nothing but home-grown mealworms with excellent results. One down side of mealworms as a pure diet for some animals is that insect larvae are very fatty and mealworms are no exception.

My Collared Lizards get mealworms as a treat, since they seem to be more attracted to them than to crickets and I don't want the Collareds getting addicted to mealworms and refusing crickets. My Chuckwalla is insane for mealworms and runs to the dish before I'm finished pouring his ration. He reminds me of a Labrador Retriever in a dog food commercial. My Desert Iguana yums down mealworms a few times each week, 20 worms at a sitting. My Horned Lizards love the white mealworms and also the pupae. The Desert Ig and Leopard Lizards love the pupae as well. My Sandfish eat nothing but mealworms and mealworm pupae, and look like little tubesteaks. I have to manage their diet to keep them from getting too fat to burrow. I have alligator lizards too, and I see the same thing with them--mealworms are too fatty to be a staple, so the als get them as a treat.

The pupae are especially convenient to use, since they don't move and can't escape. They just lie where they landed, waiting for the cage occupants to crave a snack. Like the mealworms, the pupae are rich in fats, so I use them all sparingly if possible. When the adult beetles emerge, they are soft and white for a few hours, and all the same lizards that eat mealworms go right for the white beetles. Cured, hardened beetles seem to hold little interest for my lizards, as none of them eat or even strike at the hardened beetles.

All these animals are long-term captives. I've raised skinks, anoles and Collared Lizards to adulthood on diets rich in mealworms with no problems. Mealworms don't adhere calcium and vitamin dust as well as crickets but my lizards get regular sunshine in season and that plus dusted crickets or salad for the veggisaurs seems to be working well.

In the wild, the larvae of the Desert Darkling Beetles gather under desert shrubs and shrubby trees like Palo Verde and mesquite. There, they feed on leaf litter and take advantage of minute extra amounts of moisture held among the roots. They loosen the soil with their tunneling and churn it as they come to the surface at night to feed on leaf litter. This churning and loosening benfits the plants, improving ground saturation when rare rains fall, carrying recyclable nutrients under the surface where soil bacteria and roots can get at it. For a desert reptile with a taste for Tenebrionid larvae, the ground under desert plants offers a regular mealworm buffet.

Beneath the desert plants, the dirt is easy to dig due to the larvae loosening it. It probably tastes and smells like mealworms, so small snakes like Shovel-Nosed and Banded Sand Snakes, both of which feed on Tenebrionid Larvae, know when their searching has brought them to the feast. I suspect that Desert Iguanas, Chuckwallas, Leopard Lizards, skinks, whiptails and desert Collareds like Crotaphytus nebrius, vestigium, bicinctores and desert populations of collaris are able to dig up the odd Tenebrionid larva from the loose, smelly soil under desert plants. Just my luck, in the next life I'll be back as a desert mealworm in a field of hungry whiptails.

All things considered, I guess that's fair enough.

[ Reply To This Message ] [ Subscribe to this Thread ] [ Hide Replies ]