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Superworms Vs Silkworms
In this article, we break down the complex nutritional profiles of these species. We look at protein, fat, mineral, and fiber content. Plus, we look at different situations in which each insect might be appropriate.
Nutritional Profile of Superworms and Silkworms
Experts suggest that the following nutritional profile is optimal for most insectivorous and carnivorous reptiles and amphibians:
Typical Carnivorous Reptile Diet
- High in Protein (30-60%)
- High in Fat (40-70%)
- Low carbohydrates and Indigestible Fiber
That being said, the most balanced feeder insects typically have nutrient profiles in the ranges above. These ranges, high in fat and protein, give insectivores quick, accessible energy.
We can compare Superworms and Silkworms directly, using data from a large study of insect nutritional composition:
Superworms - Fat & Protein
- Protein - 47%
- Fat - 42%
Silkworms - Fat & Protein
- Protein - 53%
- Fat - 8%
Silkworms, while they are a good source of protein, are a terrible source of fat. At only 8%, silkworms have the lowest fat content of almost any insect. That means for growing pets, underweight pets, and those that are about to reproduce, silkworms should not be a staple of the diet. An overweight reptile may benefit from slightly less fat in their diet - although it is important to make sure they are also getting plenty of exercise.
Superworms are much closer to “balanced.” With nearly 5 times as much fat, superworms are well within the recommended range of 40% - 70%. Superworms falls well within the range of both fat and protein content, which is why they're such a popular feeder for many reptile owners. But there are additional factors to consider with analyzing nutrients, and mineral superworms do fall short with mineral content.
When considering an optimal diet, minerals are an important factor. In most reptile and amphibian diets, two minerals are key: calcium and phosphorus.
Calcium plays a wide variety of roles in reptiles - from the immune system to the scales. Phosphorus is needed to extract calcium from food and utilize it properly within the body. So, a consideration of the calcium and phosphorus content of a feeder insect is important.
Experts recommend a calcium-to-phosphorus ratio in feeder insects that is somewhere around 2:1. Here are the actual mineral contents of superworms and silkworms:
- Calcium - 1.2
- Phosphorous - 8.3
- Ratio - 1 : 6.9
- Calcium - 1
- Phosphorus - 14
- Ratio - 1 : 14
Superworms show a ratio of nearly 1:7. This means you would have to add nearly 13 grams of calcium per kilogram of Superworms in order to balance out the ratio. While insect calcium dust may help balance this ratio a bit - each insect will need a huge amount of dust to become sufficient nutritionally.
Silkworms would need heavy calcium supplementation - based on unbalanced calcium-to-phosphorus ration of 1:14. This essentially means that you would have to dust every kilogram of silkworms with approximately 27 grams of calcium in order to utilize all of the phosphorus they provide. If there is no calcium to bind to, this phosphorus will need to be extracted from the bloodstream, putting a strain on your pet’s kidneys.
This is one of the reasons why it's important to gut load your feeder. Look for a gut load with a strong calcium content if feeding superworms to your pet.
When it comes to digestibility, the most important thing is fiber. Unlike humans and other omnivores that require high fiber diets, insectivores have very short digestive tracts. They do best when there is very little fiber.
Within insects, fiber almost exclusively comes from the molecule chitin - a structural protein that gives the exoskeleton rigidity. The tougher the exoskeleton, the more fiber. More fiber can make it harder for your pet to digest the insect and extract the nutrients and minerals present.
Here is the fiber content of superworms and silkworms:
- Fiber - 8%
- Fiber - 6%
Both of these insects have relatively low fiber content, considering that some insects can be as high as 20%. If we are forced to compare them directly, silkworms have a slight digestibility advantage. But, when you compare the mineral content of each species it becomes clear that even if superworms are less digestible, they will still provide a more favorable calcium and phosphorus. However, the calcium to phosphorus ratio is not ideal for superworms, and should be supplemented with calcium dust and gut load.
That being said, the low fiber content of silkworms in addition to their high protein does make them a suitable treat for most reptile and amphibian species - from leopard geckos to bearded dragons. But it's important to provide a diverse diet.
Other Factors to Consider
If you are planning on making this insect your primary feeder, you may want to start a colony. In that case, you would be good to stick to superworms. Superworms are easy to rear in a plastic tub that has a lid. While they do emit a slight odor, they can be stored out of sight in a dark place and fed your leftover fruits and vegetables. Superworms breeders will need to rotate superworms, to pupa, to beetles, and back to superworms. There is maintenance involved when breeding superworms. But it can be worth starting a colony. Here is a video guide we created that discusses how to breed superworms.
How to Breed Superworms
By contrast, the raising of silkworms is a much more complicated task. Silkworms only eat certain types of leaves and must have a very specific setup. Plus, as their name implies, silkworms produce tons of silk. While this is valuable as a textile when harvested in large quantities, it actually makes it very hard to harvest and collect individual worms for feeding.
Which Insect Will My Pet Prefer?
Both of these insects can stimulate the natural behaviors of stalking, catching, and eating. They're wiggly, squirmy, and can attract the prey-drive of many reptiles. They won't be as active as crickets or roaches, but silkworms and superworms can wiggle enough to stimulate your dormant pet, and activate their prey drive.
Silkworms are suggested only as an infrequent treat. They can be great for getting a lethargic pet moving because they look appetizing and easy to catch. For these same reasons, they can easily get boring to your pet as a regular feeder insect. Plus, since they do not have the optimal fat content or mineral content, they should be avoided on a regular basis.
Don’t Forget Variety!
While superworms do provide a better basis for an insectivore diet compared to Silkworms, they are still not perfect. Even superworms have a poor calcium to phosphours ratio. An easy solution to any diet deficiency is to introduce variety into the diet!
A highly variable diet is seen in many wild reptiles and amphibians. They eat whatever insects they can find, provided these insects do not repel them with scent or coloration. Reptiles and amphibians are mostly opportunistic feeders; they eat first and ask questions later. This gives them nutrients from many different sources that tend to complement one another. A diet that contains many different insects is much less likely to contain any nutrient deficiencies.
Regardless of the insect that you choose to make up the bulk of your feeding, it is important to offer different kinds of insects at regular intervals. This will help get your pet all the protein, fat, and minerals that they need!