Calci Worms vs. Mealworms
- Hannes Hafstad
- Feb 26
- 4 min read
Updated: Mar 2
Calci Worms vs. Mealworms
If you are a garden enthusiast and enjoy attracting and supporting life in your garden then you may know that insects are a perfect tool for this. It is easy to assume that “bugs are bugs” and that any insect will do, however, the choice between Calciworms and Mealworms is a decision that has a massive impact on the health of the wildlife you have visiting your garden. So what are they and what is the difference?
Calci Worms vs. Mealworms: What are they?
Calciworms:
Calciworms are the larval stage of the Black Soldier Fly (Hermetia illucens). Originally native to the Americas, they now live in tropical regions all around the world. They are a non-pest, non-invasive species of fly with a very short lifespan. In their larval stage, they are renowned for being one of the most sustainable protein sources on the planet. Recently, they have seen growing popularity amongst bird feeding enthusiasts as an alternative to mealworms.
Mealworms:
Mealworms are the larvae of the Mealworm Beetle (Tenebrio molitor), a species of beetle native to the Mediterranean. They have been the go-to choice for bird feeders and fishing bait for decades. Unlike the fast-growing Calciworm, mealworms grow relatively slowly, taking up to six months to complete their life cycle while feeding on dry grains like wheat and bran.
Calci Worms vs. Mealworms: The Nutrition Breakdown
Both insects are nutritionally dense and provide a significant amount of protein. Mealworms typically have more crude protein, but this comes at the expense of nutritional balance.
Nutritional Factor | Calciworms (BSF Larvae) | Mealworms |
Protein | 35% to 44% | 36% to 60% |
Fat | 25% to 30% | 30% to 35% |
Calcium Content | 2,000 to 8,000 mg/kg | 300 mg/kg |
Ca:P Ratio | 3:1 (Balanced) | 1:10 (Imbalanced) |
Exoskeleton | Softer (more digestible) | Hard chitin (Less digestible) |
[1, 2]
Calci Worms vs. Mealworms: For Wild Birds
Birds have changing needs throughout the year. During the spring, they face a particularly large challenge of finding enough food and nutrients to produce a full and healthy clutch of eggs. During this time, up to 50% of dietary calcium is used to build egg shells. When dietary calcium is insufficient, calcium is drawn from the reserves held in their own bones [3]. Helping birds find enough dietary calcium therefore helps prevent them developing weaker, brittle bones.
Feeding mealworms during this period can be a dangerous trap. Mealworms, while rich in protein, have a poor Calcium-to-Phosphorus (Ca:P) ratio, meaning it takes additional calcium to process the phosphorus, meaning the feeding leaves them in a further calcium deficit. This can lead to more calcium being pulled from bones just to balance the phosphorus, making mealworms act like a calcium vacuum. Whereas, the more balanced Ca: P ratio of Calci Worms make them a better source of minerals for birds, giving them all the calcium they need when they need it.
Calci Worms vs. Mealworms: For Hedgehogs
Insects make up a key part of a hedgehog's natural diet and so it makes sense to supplement what they can forage with more insects. However, Mealworms can also present a hidden danger to Hedgehogs. Hedgehogs love dried insects and will come back again and again for them. But, just like for birds, the Calcium to Phosphorus ratio of mealworms can cause calcium to be leached from their bones to process the phosphorus. Over time this can lead to Metabolic Bone Disease (MBD), which can have serious health implications. Because of this, there is lots of online advice to avoid feeding hedgehogs mealworms and instead to use the calcium rich Calci Worm.
Calci worms vs Mealworms: For Chickens
Chickens, even if only kept as pets, are classed as livestock and legislation is strict about what can be fed to livestock and this restricts the use of dried insects as feed. However, feeding live insects is a legal and highly beneficial practice for chickens.
All the time that chickens spend digging and scratching at the ground is to try and find live insects to eat. Our first hand experience with our Pekin Bantams is that chickens have a significant preference for live insects and they will very quickly become their favourite treat, providing mental stimulation as well as nutritional benefits.
If you would like to offer your birds a treat they are going to absolutely love:
Calci worms vs Mealworms: For Sustainability
All insects are efficient converters of organic material into biomass. However, Black Soldier Fly Larvae are famous for it. They are the ultimate upcyclers, capable of turning organic waste into high-quality protein at a staggering rate. Out-converting other insects and being significantly more productive in terms of the feed required and time taken compared to other famed animals, Calci worms are unmatched in their bioconversion and the clear pick from a sustainability point of view.
Animal | Feed Needed for 1kg of Growth | Time Required |
Calci Worms | 1.5kg (often organic waste) | 2 Weeks |
Mealworms | 3kg to 4kg (grains/bran) | 3-6 Months |
Chicken | 2kg to 5kg (high-grade soy/corn) | 6-8 Weeks |
Pigs | 4kg to 9kg (grain/protein) | 6 Months |
Cattle (Beef) | 25kg (grass/grain) | 18-24 Months |
[4, 5]
Calci Worms vs. Mealworms: Conclusion
While it may seem that choosing one type of insect over the other is an unnecessary choice, there are genuine and significant differences between them. The animals that call your garden home have needs that change throughout the year. While both Calci Worms and Mealworms pack a lot of protein into a snack that lots of these creatures enjoy, there are other factors at play. The other necessary nutrients made available need to be balanced to keep your garden life healthy. As such Calci Worms come out on top for giving everything your garden life wants and everything it needs.
Shop our collection of Caci Worms here:
References:
1: S. Lu et. al 2022
2: Noyens et. al 2024
4. Bonin. L, 2022
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