Mealworms are eaten by a surprisingly wide range of animals, from backyard birds and pet reptiles to freshwater fish, small mammals, and even humans. These larvae of the darkling beetle pack roughly 48% protein and 35% fat when dried, making them one of the most nutrient-dense prey items in the insect world. That caloric punch is exactly why so many species target them.
Wild Birds
Birds are the most well-known mealworm predators. Bluebirds are especially drawn to them, but the list of species that will eagerly take mealworms includes chickadees, wrens, titmice, nuthatches, kinglets, thrushes, and woodpeckers. These are all primarily insect-eating species, and mealworms fit neatly into their natural diet.
Live mealworms are more appealing to birds than dried ones because the wriggling motion triggers their hunting instinct. If you’re putting mealworms in a backyard feeder, a shallow dish or hanging platform works well. Storing live mealworms in the refrigerator slows their development and keeps them in the soft larval stage that birds prefer over the hard-shelled adult beetle.
Reptiles and Amphibians
Mealworms are a staple feeder insect in the reptile and amphibian hobby. Bearded dragons, leopard geckos, chameleons, and skinks all eat them readily. On the amphibian side, frogs and toads (including large species like the African bullfrog) will snap up mealworms without hesitation.
There’s an important nutritional catch, though. Mealworms have a severely inverted calcium-to-phosphorus ratio, sometimes as extreme as 1:17. For perspective, most reptiles need something closer to 2:1 in favor of calcium. Animals fed mealworms as their sole diet can develop metabolic bone disease, a condition where the body pulls calcium from the skeleton to compensate for what the diet lacks. This leads to skeletal deformities, fractures, and muscle tremors. Dusting mealworms with a calcium supplement or offering them alongside other feeder insects solves this problem.
Small Mammals
Several wild mammals eat mealworms opportunistically. Hedgehogs are classic mealworm hunters, and anyone who leaves a dish of mealworms outdoors for birds may find hedgehogs raiding it after dark. Rats, mice, and badgers will also take mealworms when they find them. Foxes are less enthusiastic but will eat them when other food is scarce.
In the pet world, hamsters, sugar gliders, and hedgehogs are all commonly fed mealworms as protein-rich treats. Mammals digest the mealworm’s tough outer shell using a specialized stomach enzyme called acidic mammalian chitinase. Research on pigs showed this enzyme breaks down mealworm shells efficiently at the acidic pH of the stomach, splitting the chitin into smaller sugar fragments the body can absorb. This means mammals don’t just eat around the shell; they actually extract nutrition from it.
Freshwater and Saltwater Fish
Mealworms make effective fishing bait for a reason: many fish species find them irresistible. Bluegill are particularly fond of them, readily striking at the small, wriggling larvae. Both largemouth and smallmouth bass take mealworms, especially in shallow water. Trout, which naturally feed on insects, are a natural match. Catfish, despite being bottom feeders, are opportunistic enough to eat mealworms when they encounter them.
In saltwater, smaller coastal species like pinfish and juvenile snapper will go after mealworms too, though they’re far more commonly used in freshwater fishing.
Spiders and Other Invertebrates
Mealworms aren’t just eaten by vertebrates. Black widow spiders prey on both larval and adult mealworm beetles. Research comparing spider feeding on larvae versus adult beetles found that the harder exoskeleton of adult mealworms changes how much nutrition the spider can extract, which is why predators generally prefer the softer larval form. Other predatory invertebrates, including centipedes and predatory beetles, will also consume mealworm larvae when they encounter them in grain stores or soil.
Poultry and Livestock
Chickens go wild for mealworms, and there’s solid production data behind feeding them. Supplementing broiler diets with just 4% dried mealworm significantly increases body weight and daily weight gain while improving feed conversion, meaning the birds get more growth per unit of food. Laying hens benefit too, with improvements in egg production and dietary quality. Japanese quail fed up to 10% mealworm in their diet showed better weight gain, higher carcass weight, and improved meat quality. The high protein and fat content of mealworms makes them a competitive alternative to conventional protein sources like fish meal or soybean meal in animal feed.
Humans
Mealworms are increasingly part of the human food supply. The European Union has formally authorized several forms of mealworm for human consumption, including dried whole larvae, frozen larvae, mealworm powder, and UV-treated mealworm powder. As of January 2025, the EU had approved multiple mealworm-based products as novel foods following safety assessments by the European Food Safety Authority. These products are intended as food ingredients for the general population, showing up in protein bars, pasta, snack foods, and baking flour.
Fresh mealworm larvae are about 60% water, but once dried, their protein content rivals or exceeds that of conventional animal proteins like fish meal and poultry meal. The flavor is often described as mildly nutty, and the larvae can be roasted, ground into powder, or baked into foods. Mealworm farming also requires far less land and water than raising livestock, which is a major reason governments and food companies are investing in insect-based protein.