Mealworms are not true worms but the larvae of the beetle species Tenebrio molitor. Feeder crickets or mealworms can be used as a staple diet for Leopard geckos, or Eublepharis macularius, as long as the insects have been eating nutritious food often sold as feeder cricket diet or gut-loading diet. Otherwise, the gecko will just fill up its stomach with the reptile equivalent of junk food. Mealworms are sold in plastic containers that can be used as a mealworm home. Small containers can be placed in the refrigerator. If there are only a few gut-loaded mealworms, place them directly into the gecko's cage.
Feed live mealworms with gut-load food at least 12 hours before feeding to the gecko. This gives the mealworms enough time to eat. Sprinkle the food into the mealworm container. The mealworms will easily find the food.
Place one slice of fresh apple or a moist potato in the mealworm container. This will give the mealworms all of the water that they need, according to "Leopard and Fat-Tailed Geckos." Replace when the slice dries out or turns brown.
Feed only live mealworms by placing directly into the gecko's cage or holding the mealworm in tweezers if that is how the gecko was trained to eat. Dead mealworms will be ignored. Also, dead mealworms may contain bacteria or other pathogens that could get a leopard gecko sick if it did eat dead mealworms. Only give small mealworms to small leopard geckos and large mealworms to adult geckos. To calculate how many mealworms a leopard gecko needs, feed two for every inch of the gecko's total length from nose to tail-tip.
Feed every 48 hours.
If there is not enough time for the mealworms to eat a gut-loaded diet, dust the mealworms with either a vitamin supplement for reptiles or the gut-loading diet. Be sure any supplements contain Vitamin D3 and calcium. Place the mealworms that are about to be fed in a plastic bag, sprinkle in some of the powder and gently shake. Then place the mealworms in the leopard gecko's cage. Leopard geckos also need unlimited access to a shallow dish of water.
Never feed only mealworms to leopard geckos. They do need a variety in their diet. Weekly treats include superworms or waxworms.