Superworms have a bit of a reputation among leopard gecko keepers and lizard lovers in general.
They’re big. They’re somewhat aggressive. And they have a thicker chitin than mealworms.
Many leopard gecko owners prefer to avoid feeding superworms to their leos out of fear that the leo will be bitten by this aggressive larvae. However, that should be the least of your concerns.
So, can leopard geckos eat superworms? We’ll get to that in a moment, but first let’s take a look at superworms themselves.
What Are Superworms?
Superworms – also known as king worms, morio worms, or by their scientific name “Zophobas morio” – are the larval form of the darkling beetle. In appearance they resemble large mealworms. However, they are easily distinguished by their size, their color, and the fact that they have mandibles.
They are a popular feeder among keepers of insectivorous animals like lizards, turtles, frogs, and even birds. They are also relatively odor free, making them a more popular option than crickets among colony keepers.
What Is the Superworm Life Cycle?
The superworm follows a similar life cycle to the hornworm:
- Larva = superworm
- Darkling beetle
Unlike the hornworm, however, superworms will not pupate if left together – in bodily contact – with other superworms and provided with plenty of food. This makes it easier to establish colonies and save as special treats for your leopard gecko than the similarly popular treat, the hornworm.
Superworms can grow up to 2 ¼” long. They look like very large mealworms, but the ends of their bodies are a much darker, nearly black color, and they have mandibles. They are also more feisty than mealworms and are known to attack when threatened.
What Do Superworms Eat?
The tropics of Central and South America are the superworm’s natural habitats. In their natural environment, superworms will eat things like:
- Fresh and decaying vegetation
- Tree bark
Those who raise their own superworm colonies have lots of high-nutrient options for feeding their superworms and helping them to thrive. Some of these options include:
- Stabilized rice bran
- Dandelion greens
- Romaine lettuce
- Sweet potatoes
However, there are fruits and vegetables that you should avoid feeding to your superworms. These include:
- Any citrus
Pro Tip: When gut-loading your superworms, be sure to feed them high-nutrient vegetables and grains. Oats are especially a favorite among breeders.
Should You Feed Superworms to Your Leopard Gecko?
If you’re a little hesitant to feed superworms to your leo, you’re not alone. Many leopard gecko keepers hear stories about superworms biting, and they politely say “Thanks, but no thanks.”
It’s an understandable – and oft repeated – concern. But does it really need to be? Well, let’s ask…
Do Superworms Bite Lizards?
Short answer, yes. Superworms are a somewhat aggressive larvae that can bite lizards. When they feel threatened, they are known to attack.
Should that stop you from allowing your leo to enjoy this tasty treat from time to time?
Not at all!
The truth is, you don’t need to worry about superworms biting your leo.
Leopard geckos have a remarkable instinct for attacking their prey head on, thus neutralizing the superworm the moment it’s in your leo’s mouth.
But even if the superworm somehow manages to bite your leopard gecko, there’s no cause for alarm.
A superworm bite will not cause your leo any serious injury. If you happen to witness a bite, be sure to keep an eye on the “bite site” to ensure it doesn’t become infected, but there’s truly no reason to be concerned.
The greater threat that superworms pose to your leopard gecko isn’t from biting, but from overfeeding.
Nutritional Value of Superworms
Like hornworms and mealworms, superworms don’t have very high nutritional value. Therefore, they should only be fed to your leo as an occasional treat. Their nutritional content includes:
- Moisture = 58%
- Protein = 20%
- Fat = 18%
- Fiber = 3%
- Calcium per kg = 177mg
- Phosphorous per kg = 2370
However, superworms can be gut-loaded prior to feeding them to your leopard gecko. By letting them feed on vegetable and high nutrient grains like oats, and dusting them with your Calcium/Vitamin D3 supplement of choice, you can transform superworms into a somewhat healthier snack.
But be careful not to feed them to your gecko too often.
How Often Should You Feed Your Leopard Gecko Superworms?
Because of their high fat content, feeding superworms to your leo too often puts it at risk of developing obesity. And if you don’t dust the superworms prior to feeding, you risk depleting your leopard gecko’s calcium levels.
So, how often can you safely feed superworms to your leopard gecko? Generally, once per week or every couple of weeks is a good rule of thumb. When feeding, offer your leo 2 or 3 at a time, but no more.
- For babies, the superworms should be no larger than ⅜”
- Juveniles can handle superworms up to ¼”
- Adult leopard geckos can take fully grown superworms
If you’re concerned about your leopard gecko getting bitten, you have two options. You can either hold onto the superworm with a pair of keeper’s feeder tweezers and let your leo grab it from there. Or you can crush the superworm’s head immediately prior to tossing it in with your leo. This way it’ll still be wriggling around, but there’s no threat of it biting.
Can Superworms Cause Impaction?
This is the other risk that ought to concern you more than a superworm biting.
Superworms have a thicker chitin than mealworms. And although a leopard gecko’s stomach will digest this over time, overfeeding superworms to your leo puts it at slight risk of impaction – just like with bearded dragons.
In addition to controlling how often your leopard gecko eats superworms, you can reduce the risk of impaction by maintaining your leo’s habitat at appropriately warm temperatures. If the habitat is too cool, the likelihood of impaction increases.
Your leo’s habitat should be kept consistently at the following temperatures:
- Cool side should be 75º
- Warm side should be in the low 90ºs
- Basking area should be between 94º and 97º
Lastly, but related to temperatures, be sure not to feed your leopard gecko superworms right before lights out. The cooling off that happens after lights out reduces your leopard gecko’s ability to digest properly.
Can Leopard Geckos Eat Darkling Beetles?
Superworms are the larva form of darkling beetles. That leads many leopard gecko keepers – and superworm colonists – to ask whether or not leopard geckos can eat darkling beetles.
Absolutely! Leopard geckos can eat darkling beetles as a treat.
Darkling beetles actually have higher nutritional value than superworms. Here are some of the nutritional values to compare with superworms:
- Moisture = 62%
- Protein = 26%
- Fat = 5%
- Ash = 2%
The low fat (5%) and high protein (26%) make them a much better feeder than superworms, especially when dusted with a Calcium/Vitamin D3 supplement. The lower fat content also makes the darkling beetle less of a risk for potential obesity. And the higher levels of ash make the darkling beetle a rich source of minerals.
However, not all leopard geckos enjoy eating darkling beetles, and some will simply turn their noses up at them.
If you decide to feed darkling beetles to your leo, make sure the beetle itself is smaller than your leopard gecko’s head, and do not feed it to babies and juveniles.
Finally, be sure to remove any uneaten darkling beetles from your leopard gecko’s tank after feeding. Although it’s rare that a darkling beetle would attack your leo – and they might actually even help keep the tank a little cleaner – they do have pincers that they may use in defense against your leopard gecko.
Takeaway: Superworms – and even darkling beetles – are fine to feed to your leopard gecko as an occasional treat, but should not be a staple of your leo’s diet. Instead, stick with crickets and Dubia roaches, and offer things like superworms only occasionally.
If you have questions or would like to give feedback, please email us at [email protected]