BSFL vs Mealworms vs Crickets: Which Feeder Insect Is Best?

If you've been keeping reptiles, backyard chickens, or other insectivores for any amount of time, you've probably had the feeder insect debate with yourself more than once. Crickets are everywhere. Mealworms are cheap. But lately, black soldier fly larvae keep showing up in the conversation, and there are good reasons for that.

Here is a comparison between black soldier fly larvae (BSFL) versus mealworms versus crickets.

The Nutritional Breakdown

Here's where things get interesting fast. Feeder insects vary a lot in what they actually deliver.

Protein is the starting point for most keepers. On a dry matter basis, BSFL come in at around 40-45% protein. Mealworms land at roughly 53% protein, and crickets sit around 60-65%. So at first glance, crickets and mealworms win on protein, but that's only part of the story.

Calcium-to-phosphorus ratio matters enormously for reptiles in particular. Most feeder insects are calcium-poor and phosphorus-heavy, which means you're constantly fighting metabolic bone disease if you're not supplementing aggressively. Crickets have Ca:P ratios of approximately 1:4.6 to 1:7.6. Mealworms are even worse, with ranges around 1:3 to 1:14. Black soldier fly larvae are the exception, they come in around 1.5:1 to 8:1 depending on what they were raised on, making them one of the only feeder insects that can meaningfully contribute to your animal's calcium intake without heavy dusting.

Fat content is another differentiator. Mealworms are famously high in fat, around 28-35% on a dry weight basis. That's fine occasionally, but mealworms as a diet staple is a reliable path to fatty liver disease in bearded dragons and obesity in leopard geckos. Crickets run leaner, around 8-22%. BSFL sit at about 28-36%, similar to mealworms, but the fat profile is different, they contain lauric acid, a medium-chain fatty acid with antimicrobial properties that you won't find in the other two.

Gut-Loading: Where Crickets Fall Apart in Practice

Gut-loading, feeding nutritious food to feeder insects before offering them to your animals, is the standard advice for improving nutritional value. In theory, it works great. In practice, crickets are a nightmare.

Crickets die constantly. A culture of 200 crickets will have dead ones every morning that need to be pulled out before they cause ammonia spikes that kill the rest. They smell. They chirp at 2 a.m. They escape. Gut-loading a leaky, dying, smelly cricket colony is a level of dedication most keepers abandon within a few months.

Mealworms gut-load reasonably well and are much easier to keep. They're slow-moving, don't climb smooth surfaces, and can be stored in bran in the refrigerator to slow development. The fat problem remains.

BSFL don't require gut-loading in the traditional sense. Their calcium content comes from the substrate they're raised on, high-calcium feed inputs (like dried eggshell or oyster shell) during the larval stage get incorporated into their bodies rather than just passing through the gut. That means dried BSFL retain their nutritional profile after processing in a way that crickets, which need to be alive and recently gut-loaded to deliver benefit, simply can't match.

Which Animals Benefit Most from BSFL?

Bearded dragons are probably the best-known BSFL beneficiary. The calcium ratio is directly relevant to a species prone to metabolic bone disease, and both live and dried BSFL are accepted readily by most individuals. Juveniles especially benefit from the higher calcium availability during their growth phases.

Leopard geckos and crested geckos do well with BSFL as a supplementary feeder. The fat content means they shouldn't be a dietary staple for sedentary keepers, but rotating them in 2-3 times per week adds variety and nutritional diversity that crickets alone can't provide.

Chickens are enthusiastic consumers of BSFL at every life stage. The larvae are also self-harvesting when raised in a proper setup, mature prepupae migrate away from the feed substrate and can be collected without much labor. Protein levels support egg production, and chickens will work significantly harder to get a larva than to peck at pellets, which matters for enrichment in confined flocks.

Fish, particularly tilapia, trout, and catfish, have been the subject of significant aquaculture research on BSFL as a fishmeal replacement. The amino acid profile is solid for omnivorous fish, and the lauric acid content has shown some promise for disease resistance.

Wild birds are generally less selective and will take dried BSFL readily. If you're running a backyard feeder station, dried larvae are a high-value addition that attracts insectivorous species that wouldn't bother with seeds.

Live vs. Dried: What Actually Makes Sense

For most applications, dried BSFL are the practical choice. They store at room temperature for months, don't escape, don't smell, don't require maintenance, and deliver consistent nutrition. Golden Grubbies from Blue Grub Farms are dried black soldier fly larvae, no additives, no preservatives, just larvae that were raised on a controlled diet and dried at the right stage to preserve nutritional quality.

Live larvae are the better choice when feeding stimulus matters, some animals won't take still prey, or you're trying to encourage a reluctant eater. The movement triggers predatory response in a way dried insects can't replicate. Squirmy Grubbies are live BSFL available for local delivery in the Denver metro area, useful if you're in Colorado and want to offer live prey without managing a full colony yourself.

The Case for Running Your Own Colony

If you're feeding multiple animals, or you keep chickens and want to close the food waste loop, raising your own BSFL colony changes the economics entirely. A colony fed on kitchen scraps, fruit, vegetable trimmings, coffee grounds, spent grain, produces larvae continuously at near-zero input cost after the initial setup.

The equipment matters. A purpose-built ramp system handles the self-harvesting behavior of prepupae automatically, so you're collecting larvae rather than digging through a substrate. The BSFL Bin Kit includes the ramp, collection insert, entrance pod, egg tree, and instructions, everything except the bin itself, which you either already have or can pick up for a few dollars.

FAQ

Can I replace crickets entirely with BSFL for my bearded dragon? For adult bearded dragons, BSFL can make up a significant portion of the insect portion of the diet, many keepers rotate them as a primary feeder alongside dubia roaches. For juveniles, variety is generally better than relying on any single insect. BSFL don't replace the behavioral enrichment of chasing live crickets, but nutritionally they're a strong option and significantly easier to manage.

Are mealworms ever the right choice? Yes, mealworms are fine as an occasional treat or enrichment item. The problems arise when they become a dietary staple. If your animal loves them and you're already offering a varied diet with proper supplementation, a few mealworms a week isn't going to cause harm. The fat and phosphorus concerns are real, but they're dose-dependent.

Do dried BSFL still have the same calcium content as live larvae? Substantially yes. The calcium in BSFL is structural, it's in the exoskeleton and body tissues, not in gut contents that disappear when the insect dies. Dried larvae retain most of their calcium profile. The main thing lost in drying is moisture and some heat-sensitive compounds, but the mineral content holds up well. That's one of the reasons dried BSFL are worth using even compared to live insects, the nutritional delivery is more predictable.

Blue Grub Farms is a BSFL farming operation based in Aurora, Colorado. We raise black soldier fly larvae, sell farming equipment, and think a lot about insect nutrition.