Banquet of Mealworms for Bearded Dragons

Mealworms for Bearded Dragons

Tenebrio molitor, typically known as mealworms and darkling beetles, can be part of your bearded dragons diet at pupae, mealworms and beetle stages. Mealworms offer variety, but moderation is key.

Mealworms for bearded dragons need to be fed in small amounts. Feeding large large quantities of mealworms or relying solely on them has been shown to cause calcium deficiency such as found in a study by Klasing et al., (2000) on chicks and may cause metabolic bone disease in reptiles (MBD) (Brown, 2012). For reptiles with MBD, consult your vet before feeding mealworms.

1. Nutrient Value of Mealworm Beetles & Mealworms for Bearded Dragons

Finke (cited in Van Huis et al, 2013) compared the nutritional value of mealworms (dry weight, fasted 24 hours) to beef and found:

• The fat content of mealworms is less than beef, but beef had slightly higher protein.
• Mealworms had higher vitamin content except for B12.
• Mealworms had similar potassium, iron, zinc and other minerals.
• Numerous variations in amino acids and fatty acids between beef and mealworms.

Barker et al., (1998) and Oonincx & Dierenfeld, (2011) assessed the nutrient value of the mealworm as dry matter as:

• Calcium: Regular mealworms and supermealworms have low calcium levels, around 0.12%.
• Phosphorus: Phosphorus levels are relatively high across all mealworm types, ranging from 0.83% to 1.42%, contributing to an imbalanced calcium-to-phosphorus (Ca:P) ratio.
• Fat: The Tenebrio beetle has 1/2 of the fat content that its larval stage has.
• Vitamins: Overall, the levels of fat-soluble vitamins and nutrients in beetles are low.
  • Vitamin E: Regular mealworms and supermealworms have moderate Vitamin E content, approximately 30-32 IU/kg.
  • Vitamin A: Vitamin A content varies, with regular mealworms at about 811 IU/kg DM and supermealworms at 972 IU/kg.
• Protein: Tenebrio beetles have a higher protein content (51%) than in their larval stages. This is likely due to the beetles’ more developed exoskeletons, which could also make them harder to digest.
• Chitin (as NDF): Chitin content, indicative of dietary fiber, is present in mealworms, with a percentage of around 15% of, contributing to gut health but also potentially affecting protein digestibility.

Finke (2002) assessed the nutrient value of mealworms as is (in their wet form) to be:

2. Mealworms for Bearded Dragons: The Case Against Them

The main concerns with feeding mealworms are:

• Mealworms have a poor calcium to phosphorus ratio: Take it to an acceptable level with the right diet and gut loading of the meal worm.
• Mealworms have a high level of fat: Mealworms should make up no more than 10% of the diet (Brown, n/d).
• The level of chitin in mealworms: Feed small mealworms or those that have just shed, they will have a much lighter skin color (Brown, n/d).

3. Can Bearded Dragons Eat Mealworm Beetles?

Bearded dragons eat mealworm beetles. The base of an insectivorous animal’s diet should consist of adult insects like crickets, cockroaches, or mealworm beetles rather than larvae (Chameleon Forums conversation with Mark Finke, 2023). Bearded dragons start out life as insectivores but become omnivores. Regardless, the information is still of value to bearded dragon owners.

The larvae stage of mealworms for bearded dragons can be too high in fat, which is not be ideal as a primary food source. Variety in a diet is important for meeting nutritional needs. The mealworm beetle may offer more variety and lower fat.

4. Natural Stimulation Value

Mealworm pupae are limited to an occasional wriggle; they don’t offer your bearded dragon a chance to fully interact with its environment and encourage natural behaviors. Larva can wriggle around, and beetles can move faster. Beetles may also provide some benefit for the bearded dragons teeth by aiding in cleaning.

5. How many Mealworms can a Bearded Dragon Eat?

How many mealworms a bearded can eat is covered in the guide on ‘how many bugs can a bearded dragon eat’.

Enchancing the Nutritional Value of Live Mealworms for Bearded Dragons

1. Key Points

• Mealworms are better fed Pollard than wheat germ which is also their housing substrate.
• A moisture source is required and usually provided through vegetation.
• Mealworms fed a cabbage, carrot, and flaxseed diet have improved nutritional value.
• Vegetable mix may be an all-round suitable wet feed.
• Feeding potato may increase the fat content dramatically.

How valuable live mealworms for bearded dragons are is directly influenced by the diet they are reared on and finally by their gut loading.

2. Optimal Diet of Mealworms for Bearded Dragons

Mealworms typically thrive on dry feeds, such as wheat germ, and require moisture, which is usually provided through vegetables. However, different feeds have a significant impact on the nutritional quality of the mealworms.

A suggested wet diet (added to their dry feed) for mealworms shown to improve their overall nutritional value is:

• Cabbage,
• Carrot, and
• Flaxseed (or flax oil).

In addition, Brown (n/d) recommends using Pollard or Mill Runs for the dry feed because they have lower levels of phytic acid. Phytates in bran or whole grains can bind with calcium and magnesium, making these minerals hard for reptiles to absorb. Even if calcium is present, it won’t be absorbed if mealworms are fed high-phytate diets.

Pollard and Mill Runs come from the inner parts of grains and contain fewer phytates. This makes them better for gut-loading. By feeding mealworms these products, reptiles can absorb more calcium, reducing the risk of health issues like metabolic bone disease. Using normal cereal products, like bran, can prevent reptiles from getting the calcium they need for healthy bones.

3. β-carotene in Mealworms for Bearded Dragons

Crickets and superworms are a better source of β-carotene compared to mealworms. For example, crickets have 2.72 mg/kg β-carotene whereas mealworms have 0.076 mg/kg of β-carotene (Finke, 2015). The reason for this lower level may be due to the size and age of the mealworms, as smaller mealworms tend to have less fat and fewer nutrients.

4. The Impact of Different Feeds on Mealworm Nutrition

When it comes to feeding mealworms for bearded dragons food, some feeds are better than others. A study by Noyens et al., (2023) experimented with some wet feeds to add to the dry wheat bran feed to supply moisture. Regardless of the wet feed the only mineral content that improved in the mealworms was calcium, iron and manganese.

4.1. Mealworms on Potato Cuttings

On potato cuttings mealworms:

• Doubled their fat,
• Reduced their macro and microminerals, and
• Increased their unhealthy fats (saturated and mono-unsaturated fats) while reducing their healthy fats (called poly-unsaturated fats).

4.2. Mealworms on Wet Feeds made a Big Difference to Nutritional Value

Dragojlović et al., (2022) found that wet feeds (in addition to the dry feeds) altered nutrient composition of mealworms:

• Carrots reduced fat content and increased crude fibre.
• Cabbage improved most amino acid content although it had a negative effect on methionine.
• Flaxseed increased alpha-linolenic acid (ALA), an omega-3 fatty acid, by 10 times and the balance between omega-6 and omega-3 fatty acids was lowered to a favorable ratio of 2.
• Cabbage, carrot and flaxseed resulted in the mineral content of mealworms improving.

4.3. Flax Cake Anyone? Bumping up the Omega-3 & 6 Values

Bordiean et al., (2022) also found that the addition of flax cake (specifically flax oil) to the mealworms’ diet balanced the omega-6 and omega-3 fats in the mealworms more favorably. Essentially, feeding mealworms flax cake helped make them healthier to eat from a human’s perspective by improving the balance of good fats inside them.

5. Gut Loading Mealworms

5.1. Improving Calcium in Mealworms for Bearded Dragons

Naturally, mealworms for bearded dragons are low in calcium and high in phosphorus.

Mayer (2014) recommends calcium content for gut-loading mealworms at 9% (or 9 g of calcium per 100 g of mealworms). It’s crucial not to exceed 12%, as mealworms may avoid food with higher calcium concentrations, reducing their overall activity (Mayer, 2014).

Based on 10 small mealworms (each weighing 0.12 grams) at 9% calcium that would equate to 0.108 grams of calcium per 100 grams of mealworms. A pinch of calcium will weigh around 0.3 grams, so this means you need 1/3 of a pinch of calcium.

5.2. Enhancing Vitamins in Mealworms

To enhance the nutritional value of mealworms, Finke (2003) also recommends a range of vitamins (see table below). However, sourcing a multivitamin for home use that matches these ratios is unlikely. A good quality multivitamin with a broad spectrum of nutrients should suffice for meeting most of the gut-loading needs. Use multivitamins at the rate recommended by the manufacturer.

For gut loading purposes with mealworms, a pinch per 10 mealworms should be adequate. Insects are dusted with both calcium and multivitamin powders before feeding according to schedules. Again, see manufacturers instructions.

5.3. The Magic Formula for Gut Loading: Getting it Right

Several studies support the value, success, and timing of gut loading:

• Latney et al. (2017) achieved a calcium to phosphorus ratio of 1.3:1 by using a calcium-enriched cricket diet.
• Klasing et al. (2000) successfully added 8% calcium to a broiler mix for chicks, improving the calcium to phosphorus ratio within 24 hours when mealworms were fed a calcium-supplemented substrate.
• Anderson (2000) also demonstrated that within 24 hours, mealworms could increase their calcium to phosphorus ratio using a calcium-fortified commercial diet.

Additionally, research by Gorst et al. (2015) showed that even when mealworms were starved for 12 hours, they retained their nutrient value, maintaining calcium levels in their gut for at least a day after gut loading.

Do Mealworms Cause Impaction in Bearded Dragons?

There is potential for bearded dragons to be constipated or impacted from mealworms given the wrong conditions. Wright, et al., (2008) and Brown (2012) discusses some of those conditions being:

• Incorrect food items including too many mealworms especially:
  • If not gut loaded to improve deficiencies in nutritional value, and
  • Fed at the wrong stage of the mealworm’s life. After molting is ideal.
• Insufficient roughages (e.g. bearded dragon is not eating greens),
• Poor environment conditions such as incorrect heat and humidity,
• Dehydration,
• Insufficient exercise,
• History with metabolic bone disorder.

As a matter of interest, chitin is used in a wide range of applications. It has anti-bacterial, anti-viral and anti-fungal properties which make it useful in medical and health care products such as drug capsules, wound healing products and prebiotics. Other applications chitin has also been found to be useful for include wastewater treatment, bioenergy, agriculture and absorbing pollutants (Khoushab and Yamabhai 2010).

Conclusion of Mealworms for Bearded Dragons & Their Nutritional Value

Mealworms are just one of the insects bearded dragons can eat. When fed in moderation and properly gut-loaded, they can be a great addition to your bearded dragon’s diet.

The mealworms high fat content as larvae and poor calcium-to-phosphorus ratio at any age means they should never be the primary food source. By carefully managing their diet, giving them a variety of feeders, and focusing on gut-loading, you can enhance the nutritional value of mealworms. By doing so, you can promote a healthier, more balanced diet for your bearded dragon, reducing the risk of metabolic bone disease and other health issues.

References

• Anderson, S. J. (2000). Increasing calcium levels in cultured insects. Zoo Biology, 19, 1–9.
• Arnold Van Huis, Itterbeeck, J. V., Klunder, H., Mertens, E., Halloran, A., Muir, G., & Vantomme, P. (2013). Edible insects : future prospects for food and feed security. Food And Agriculture Organization Of The United Nations.
• Bordiean, A., Krzyżaniak, M., Aljewicz, M., & Stolarski, M. J. (2022). Influence of Different Diets on Growth and Nutritional Composition of Yellow Mealworm. Foods, 11(19), 3075.
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