Table of Contents

Crickets Vs Black Soldier Fly Larvae

Table of Contents

Crickets are often considered the most popular feeder insect for reptile and amphibian pets.  They have high quantity of lean protein, and they are inexpensive.  But they are missing some critical nutrients that many reptiles require.  There are workarounds to include these nutrients with a cricket-diet.  However, those critical nutrients are naturally abundant in the nutritional profile of black soldier fly larvae.  

Black soldier fly larvae (BSFL) are an amazing, under-the-radar feeder insect for many reptiles and amphibians.  They can fulfill the calcium requirements that these amazing pets need, while also providing the protein, fat, and fiber needs for every bearded dragon and leopard gecko.

In this article, we will look at the scientific data analyzing BSFL and crickets, and compare these results directly. First, we take a look at fat and protein content. Then, we will take a look at the important minerals present in both  crickets and black soldier fly larvae, and which insect is more digestible. Before we wrap up, we analyze each insect for its ability to attract and incite natural behaviors in your pet! Check it out!

Nutritional Profile for Reptiles and Amphibians

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

High protein and fat are common to all carnivorous diets - coupled with low indigestible fiber. This allows the energy from the protein and fat to be easily absorbed and incorporated into the body. Omnivorous lizards, turtles, and amphibians often have a higher tolerance for fiber, but they will get a bigger benefit from low fiber insects.

So, let’s see discover how crickets and Black Soldier Fly Larvae stack up to this “ideal” standard, based on information compiled in this large study of insect nutritional composition:

Cricket Fat and Protein Content

• Protein - 66%
• Fat - 24%
  
  

Black Soldier Fly Larvae (Adults) Fat and Protein Content

• Protein - 45%
• Fat - 36%

Crickets are made of more protein than BSFL.  This is good for younger bearded dragons.  However, if we take the aggregate age of all reptiles, crickets are slightly too high in protein.  This isn't a bad thing, and can still be a respectable staple feeder.  But their fat content is on the low side.  Fat is important because it's how animals store energy.  But this low fat content doesn't offer enough for older reptiles, or female reptiles looking to reproduce.

Compared to black soldier fly larvae, we can see that the BSFL fall in that sweet spot for both protein and fat.  They have enough protein to satisfy younger reptiles, while still providing enough fat for the older ones.  So if you have reptiles or amphibians that are ready to breed, then the fat content in the black soldier fly larvae will be a better option.  

The fat and protein in both crickets and BSFL are comparable enough that they could almost be used interchangeably.  But, the black soldier fly larvae outperform crickets in both calcium and phosphorus, two critical minerals that reptiles and amphibians require for their health.  

Mineral Content - Calcium and Phosphorus

Of the many minerals that your pet needs to thrive, calcium and phosphorus are by far the most important. Captive reptiles often suffer from calcium deficiencies. Since phosphorus helps the body absorb and utilize calcium, it is equally important. 

In fact, the balance of calcium and phosphorus is more important than the level of calcium by itself. Without the right balance of calcium and phosphorus, many reptiles and amphibians can develop dangerous symptoms that can even lead to death!

Experts recommend a calcium-to-phosphorus ratio in feeder insects that is somewhere around 2:1. Here are the actual mineral contents of crickets and Black Soldier Fly Larvae:

Crickets (g/kg) Calcium and Phosphorus Ratio

• Calcium - 2.1
• Phosphorus - 7.8
• Ratio - 1 : 3.7
  
  

Black Soldier Fly Larvae (g/kg) Calcium and Phosphorus Ratio

• Calcium - 24
• Phosphorus - 9.2
• Ratio - 2.6 : 1

Amazingly, BSFL are almost perfectly balanced when it comes to calcium and phosphorus content! They contain the perfect 2:1 ratio. This means that BSFL likely do not need to be dusted with a calcium supplement prior to feeding. Plus, they have massive amounts of calcium and phosphorus, compared to many other species. This makes them an excellent choice if your animal has a nutrient deficiency that you are trying to fix. It also makes BSFL a great choice as your main feeder insect!

By contract, crickets miss the mark by a long shot.  Their high level of phosphorus, overwhelms the small amount of calcium, which means their mineral content is insufficient for many bearded dragons and leopard geckos.  Because of this, it's critical to dust your crickets with calcium powder, to ensure your crested gecko is getting the required minerals their diets need.    

Digestibility

If your pet can’t digest the minerals and nutrients in their food - they might as well not eat it! When it comes to feeder insects, the most important aspect of digestibility appears to be fiber content.

Insectivorous and carnivorous reptiles and amphibians do not process fiber well. They have short digestive tracts, which cannot support the necessary microbes to break down complex fiber molecules. Omnivorous pets are less restrained by fiber content because they are used to breaking down tough plant fibers. However, even an omnivorous bearded dragon will benefit from less fibrous insects that provide more mineral content.

The fiber that insects produce is called chitin. It is a crucial part of the exoskeleton - the tough outer covering of many insects. Insects with high chitin content often have a very tough exoskeleton that is very hard to digest and holds on to many of the nutrients that your pet needs.

Even though crickets have a much more complex exoskeleton compared to BSFL, each species contains approximately the same amount of fiber depending on their age:

Cricket Fiber Content

• Fiber - 12%
  
  

Black Soldier Fly Larvae Fiber Content

• Fiber - 8%

Crickets have a high fiber content, and this is due to their chitin content.  This statistic is slightly misleading, because the older crickets (3/4" and adult sized) have the most developed chitin.  Younger crickets are still developing, and are more comparable to the 8% fiber content that you can find in black soldier fly larvae.  

Black soldier fly larvae (BSFL) of any age have about 8% fiber content.  This makes them much easier to digest for a reptile with a shorter digestive track.  And since black soldier fly larvae already offer the preferred mineral content, they appear to outperform crickets as the preferred feeder for your pet.  

Additionally, BSFL have a much higher level of minerals. In part, this is because they are storing lots of minerals and energy so they can undergo complete metamorphosis and become a fly. 

So, if you have a bearded dragon or leopard gecko that needs calcium, BSFL are the perfect choice! 

Other Factors to Consider

Both BSFL and crickets can be reared in captivity, though crickets are much easier to raise, and breed much faster, making them less expensive.  

A cricket habitat will perform best between 85 and 90 degrees.  They will literally eat anything.  However, since you're raising them to be a feeder insect, you'll want gut-load them with vegetables or a dry gut load mix.  We created a detailed instructional video on how to breed crickets here:

By contrast, BSFL are maggots. Like all maggots, they create quite a bit of odor and mess when reared in a captive environment. Unlike crickets, adult Black Soldier Flies are fully capable of long-distance, sustained flight. This means you will have to have them in a secured tank or netted facility in order to keep them contained.   But keep in mind, these flies do not bite or sting, despite their large appearanace.

Further, the smell they produce is similar to a compost pile. These worms will eat anything - from food scraps to cardboard. While the smell is tremendous, it can be mitigated by adding fresh soil, feeding in even intervals, and using air fresheners. Plus, they create a very nutrient-rich compost (frass) that you can use on your plants! But for most people, the escaping flies and smell will be very undesirable. Luckily, if you want to feed BSFL, they are pretty cheap online and can be kept in the maggot stage for a long time.

Which Insect Will My Pet Prefer?

We all love to see our pets displaying their natural behaviors. Feeder insects can encourage these behaviors in a big way. Everything from observing to capturing insects are natural behaviors in many reptiles and amphibians. Displaying these behaviors is a sign that your pet is happy and healthy, and should be encouraged as much as possible!

Crickets offer one advantage in this respect in that they have legs and are very active. Crickets will run, hide, and dig into the substrate. This will give your lizard a chance to hunt - a very complex behavior that stimulates your lizard to exercise and problem solve. 

While BSFL are not nearly as quick or mobile as crickets, they do offer several benefits. First, they wiggle and crawl like crazy. This is sure to get your gecko’s blood pumping! In nature, insectivores often gorge themselves on maggots and grubs when the opportunity arises. Plus, while the adult flies have more fiber and fewer nutrients compared to the maggots, they can be a fun way to engage your lizard and can be a great feeder for chameleons!

Don’t Forget Variety!

Both Black Soldier Fly Larvae and crickets offer optimal amounts of fat and protein.  This is great for young reptiles, or reptiles that are bound to start breeding and reproducing.  

BSLF have a very high mineral content. If they are the sole form of insect you feed, your reptile may actually develop a mineral overload. Feeding different kinds of insects every now and then drastically reduces the chance of overload and will get your pet nutrients and minerals that BSFL do not have!

Likewise, crickets are a respectable staple feeder.  But they do not have the same mineral profile that black soldier fly larvae offer, which means they need to be both dusted with calcium dust, and gut loaded.  And as long as these steps are met, crickets can rank as well as BSFL for mineral content.