Before You Bug Out, Here’s What You Need to Know About Insects as Feed

By KeaGrace on Mar. 6, 2017


When it comes to our cold-blooded friends such as lizards, salamanders, frogs, snakes, tarantulas, turtles and fish, diets vary widely. Some species of reptiles eat only plant materials (herbivores), while others require protein from live animals in order to survive and thrive (carnivores). Some species are omnivores, meaning they eat a mixed diet of both plants and animals. And finally, cold-blooded critters that rely primarily on insects or other invertebrates for their dietary needs are called insectivores. Many omnivorous reptiles and amphibians fall into this category since they require insects and other invertebrates to meet their nutritional requirements. If your pet requires and enjoys insects, we’re here to guide you through the process.

Insectivore Basics
In their natural environment, some insectivores seek out and eat only one or two species of insects, but there are others that prefer to prey on a dozen or more types of insects a day. Since tendencies, preferences and requirements vary so widely among insectivores, keeping them as pets can require a lot of careful research to ensure you feed them properly. It’s important to note that different types of insects offer different nutrients and ratios of nutrients. So even if your pet is a specialist (meaning they naturally prefer to eat only a few types of prey) you should offer a varied selection of species-appropriate foods. For generalist reptiles and amphibians, or those who happily enjoy a wide assortment of insects, it’s even more important to provide variety in their diet.

Dietary requirements can differ from species to species. For example, the garter snake and the ball python are both clearly snakes, but their diets are made up of radically different food sources. While garter snakes will eat a varied diet of insects, earthworms, fish, rodents and amphibians, ball pythons eat only rodents. Feeding them the same diet could result in a very sick and unhappy snake.

Regardless of the species of your insect-eating reptile, arachnid or amphibian one thing is certain: It is your responsibility to ensure your animals’ nutritional needs are met. Always research your pet’s dietary needs and feeding preferences, and if you’re in doubt, consult an experienced herpetologist or veterinarian who specializes in reptiles and amphibians. Many insect-eating species require:

  • Varying balances of micro- and macronutrients
  • Different sources of insects and other invertebrates
  • Differing methods of keeping and preparing insects

Types of Insect-Eating Pets
There are thousands of species of reptiles, amphibians and fish, and even more species of arachnids and insects. In fact, researchers believe there are more than 900,000 distinct species of insects and that insects represent close to 80% of the world’s species. Out of all the hundreds of thousands of species of reptiles, amphibians, fish and insects, only a handful are insectivores. 

Commonly kept cold-blooded pets that require insects as part of their diet include multiple species of lizards, monitors, salamanders, newts, turtles, tortoises, frogs, toads, fish and snakes. Some reptiles, such as iguanas, only eat insects when they are very young or incidentally during routine feeding on plants. They should not be routinely offered insects as food, because they aren’t true insectivores. Several types of insectivorous invertebrates are regularly kept as pets, including beetles, praying mantises, scorpions, tarantulas, other spiders and other large predatory bugs.


Husbandry needs vary radically from species to species. Even though the insects we’re discussing are raised to be food for pets, there are specific care requirements pet parents should follow before the insects are used. In fact, the dietary needs of some species are so different that various members fall under distinct categories, such as tortoises! Some tortoises are strict herbivores, others are omnivores and still others require a diet comprised primarily of animal-based proteins. It is impossible to generalize when it comes to reptiles’ and amphibians’ diets, even within the same species. When deciding which insects to feed your pets, take the time to research your particular species and type.

Gut Loading and Dusting
Any reptile or amphibian you keep as a pet is fully dependent on you to provide for its needs. This includes a properly sized, clean and environmentally appropriate habitat as well as correctly prepared prey. In the case of insectivores, it is not enough to simply offer species-appropriate insects and other invertebrates, because the nutritional value of insects fed as prey comes solely from the insect’s diet. To prevent your pet from developing diseases, bone disorders or other health problems due to improper diet, it is essential to carefully source and prepare your pet’s food. The most common ways to ensure insects offer a source of balanced and complete nutrition are to gut load and dust them prior to feeding.

  • Gut Loading

    In a nutshell, gut loading involves feeding prey insects a diet of extremely nutritious foods so the nutritional value of the bug itself increases. Gut loading is necessary because insects are invertebrates, meaning they do not have a skeletal structure. As such, their body chemistry lacks calcium, but is very rich in phosphorous. If a reptile or amphibian is only fed insects that aren’t gut loaded or otherwise supplemented, they will develop metabolic bone disease (MBD) over time as a direct result of the calcium-phosphorous nutrient imbalance. An insectivore that is not supplemented will begin to leech calcium from their bones in order to supply their bodies with the metabolically required nutrient, and attempt to correct the overload of phosphorus. As the bones (or shells in the case of turtles) continue to lose calcium, they become soft, brittle and malformed. Eventually, the condition can become very severe if untreated.

Always guarantee that all insects fed to your pets are properly prepared in the manner best suited for their species (crickets will be gut loaded differently than mealworms or roaches). If you purchase dried or freeze-dried insects or commercial diets, verify they received proper preparation prior to feeding them to your pet.

  • Dusting

The second method to create proper nutrient balance is dusting, which requires coating a pet’s meal in a specially formulated calcium or multivitamin supplement. This process is done right before offering the insects to the reptile, amphibian or insectivore. Dr. Thomas H. Boyer, a specialist veterinarian at the Pet Hospital of Peñasquitos’ Reptile and Amphibian Practice, suggests that all insects being fed as a primary diet should be dusted with powdered calcium. Any common form of calcium is acceptable, including calcium gluconate, citrate, carbonate (which is most biologically absorbed) or lactate, as long as it does not include any phosphorous. A multivitamin supplement should never be offered as the sole source of supplementary calcium for your insectivore, regardless of what the label says about the supplement’s calcium content.

Using a cricket or insect shaker is one of the easiest ways to dust your insects. Load the cap with the appropriate amount of supplements, insert the bugs, shake gently to coat them, and then wait for 60 seconds prior to removing the insects to feed to your pet. The shaker can be cleaned with dish soap and water. Make sure it is fully dried between uses.

If you’re brand new to insectivore feeding and you don’t yet feel confident preparing insects—or you don’t want to bother with gut loading—you can feed a pre-made mixture specifically designed for gut loading. Alternatively, you can opt to feed Vita-Bugs®, which are insects and other invertebrates specifically raised for exceptional nutrition. They come already gut loaded to offer the same ingredient makeup as the insects reptiles and amphibians would usually forage for in their natural environment. Vita-Bug varieties include crickets, mealworms, superworms, waxworms and calciworms. 


Types of Insects to Feed
While there are a lot of insects and other invertebrates, your selection of food items will be limited by your pet’s needs, availability, cost and how much time, energy and effort you are able to put into food storage. Crickets, mealworms, earthworms, waxworms and fruit flies are common and readily available options at your local pet store. More choices include butterworms, roaches, silkworms, tomato hornworms and Phoenix worms. 

  • Crickets
    Crickets have been a dietary staple for many insect-eating pets kept in captivity. They’re happily accepted by many varieties of insectivores, and they’re nutritious and balanced when properly prepared via gut loading and dusting. Crickets gut load easily and are great delivery systems for nutrients and supplements. There are many species of crickets in varying sizes from extra small to large, suitable for the smallest to the largest insectivores. Crickets are hardy, easy to breed and raise, and their low cost makes them one of the top choices. They live for 8 to 10 weeks when cared for properly, so make sure to buy young crickets, or set up a breeding program so you always have a supply ready.

To keep live crickets, place them in a smooth-sided container or a specially designed cricket keeper. Make sure they have cool, dark hiding places available and a ready source of water. A damp sponge is the easiest way to provide your crickets with water in a way that prevents drowning, which happens very easily. Crickets should be fed a high quality commercial cricket diet, commonly called cricket chow (be sure to check the label since not all commercial cricket food contains the necessary nutrition to gut load properly). Prior to feeding them to your pet, you need to gut load them for several days. During the gut loading process, feed your crickets dried milk, white or sweet potatoes, carrots, fruit, mixed seeds and nuts, crushed dog food and/or wheat bran.

  • Worms
    The various types of worms available as insectivore food, including waxworms, mealworms, earthworms, butterworms, hornworms and other specialty worms. All types provide a great balance of protein and fat as well as high moisture content, which helps prevent dehydration. Each species has its pros and cons—and some make great staples while others are better off to be used as supplements or treats. Many species of feeder worms can be stored in the fridge until you’re ready to feed them. For the worms that can’t be refrigerated, such as superworms, store at room temperature in a plastic container with some uncooked oatmeal and a slice of potato.

When it comes to nutrition, waxworms and butterworms offer double the calcium compared to other feeder options, but they’re not usually used as a staple food. However, they are a great treat, and so are Phoenix worms (another high-calcium active worm that stimulates the appetite of finicky eaters). Tomato hornworms have the mass of 20 crickets, which makes them great for reptiles and amphibians that need to gain weight or need extra nutrition and hydration. Silkworms and mealworms are common staple options for most insectivores. Mealworms are easier to find but they have a hard exoskeleton, which can limit their nutritional value. Silkworms are much higher in calcium. And finally, earthworms are a great source of several nutrients, including vitamins A and E. They are shipped and kept in a plastic container pre-loaded with substrate and food, and they can be stored in the fridge.

Properly stored and refrigerated worms enter a state of dormancy, which means they can remain in storage for weeks, if not months. Once they’re brought out of the fridge and exposed to room temperature, they reanimate and can be fed. 

  • Tropical Roaches
    Roaches are incredibly high in protein, yet low-fat and high in moisture. These elements make them ideal for many species of insectivores. While it can be difficult to get over the stigma attached to roaches, there are a multitude of benefits to these insects. The dubia roach is especially easy to keep. They don’t give off a potent odor, jump, fly or bite, plus they can’t climb and they’re quiet. You can keep them in a plastic bin and feed them fruit, vegetables, nuts and dog food. They breed prolifically, so they are a ready and convenient source of food for your reptiles or amphibians. They also live 12 to 18 months, which is the longest lifespan of any common and high-nutrient feeder insect.
  • Fruit Flies
    Fruit flies are a great food source for small lizards and amphibians as well as hatchlings. There are two primary fruit fly species available: Drosophila hydei and melanogaster. While the first species reproduces more rapidly, the second is slightly larger. Both are easy to care for and do not need to be fed anything. When it’s time to feed the flies to your reptile or amphibian, tap the fruit fly container lightly. (This causes the flies to fall to the bottom of the container so they do not escape when the lid is removed.) Then gently tap the container over your pet’s tank until the desired number of fruit flies falls out. These tiny insects are very nutritious and offer variety to many pets’ diets, and if dusted, they can be fed as a staple food source. Commercially-available flightless fruit flies are a low-maintenance choice because they won’t fly around the house when it’s time to feed them to your reptiles or amphibians. A notable advantage of fruit flies? They don’t make noise like other live feeders do.

Feeding Techniques

Opinions vary when it comes to feeding insects to pets. A common method is to place live insects or other invertebrates in a pet’s habitat, and then allow the reptile or amphibian to hunt and eat them. While feeding live isn’t usually recommended for reptiles and amphibians that require vertebrate prey, such as mice or rats, it is highly recommended for most species of insectivores that eat only invertebrate prey. Many species of reptiles and amphibians feed only on moving prey; the mental stimulation of actively hunting and acquiring food can help them be more satisfied.

When offering live prey to your insectivore, make sure the food is properly sized for your pet. As a general rule of thumb, when it comes to feeding lizards, the prey animal should be smaller than the distance between your pet’s eyes—although some experts say it shouldn’t be any larger than 50 to 100% of the width of the reptile or amphibian’s head. Only provide as many insects as your pet can eat in one meal. Until you’re familiar with that amount, count the bugs before placing them in the habitat and remove any uneaten prey after several hours as they can harm your pet. Some insectivorous species require feeding once a day or every other day, and others—particularly juveniles—can eat as frequently as two to three times a day. Always keep in mind that since the exoskeleton of invertebrates can’t be digested, it’s always healthier to feed several small insects as opposed to one large one.

There are alternatives to feeding live prey. Crickets and mealworms can be purchased frozen or roasted, and some herpetologists suggest feeding non-live prey for the safety of your insectivore. Other types of prepared or pre-killed diets for insectivores include dried or canned wet foods. Dried foods must be soaked in water prior to feeding for most species of reptiles and amphibians, and all types of canned or pre-killed insects can be made more exciting to your animal by moving them around with a pair of forceps to simulate live prey. This technique is especially helpful when switching insectivores used to eating live prey to pre-killed prey.

While caring for most insects used as food is straightforward, it does require additional time and energy. Many people find it more convenient to feed pre-killed prey since there is no need to raise, feed, house or prepare it in any way. Additionally, feeding live prey comes with risks, even with prey that seems as harmless as a cricket or grub. Melissa Kaplan, one of the most widely published herpetologists in the world, notes that crickets and mealworms are “fearless and hungry.” “[They] will gnaw away at the skin and seek moisture from the eyes of healthy reptiles and amphibians when left unattended in an enclosure without proper food and moisture for them,” she says. While that’s quite graphic, it’s an important reminder to monitor all feeding.

Commercial diets, which include canned, blended or other presentations, are relatively new to the reptile and amphibian feeding scene. Always carefully evaluate food sources for nutritional soundness and compatibility with your species and type of insectivore. Supplementation may be required for some commercial diets; read all packaging and check the micro- and macronutrients of the food for suitability. Many pet parents opt to feed a blend of live or home-prepared insects and pre-killed insects so they can ensure nutritional completeness.

Final Precautions
When feeding your reptile or amphibian, always prioritize safety and health. If the food you plan to feed to your insectivore looks sickly or dead (and it isn’t meant to be), don’t feed it. Never put food in your pet’s habitat and leave it longer than a few hours, particularly in the case of reptiles that sleep at night, as their prey may attempt to prey on them while they’re sleeping. Always wash your hands before and after handling your pet’s food. Finally, take the time to enjoy your pet. Feeding insectivores can seem overwhelming, but there are valuable resources to help if you’re uncertain. Get in touch with a pet care specialist at your local pet store or your veterinarian.

Do you have a pet that eats insects? Share your feeding tips in the comments below.


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About the Author
  • Keagen "Kea" J. Grace CPDT-KA, CTDI is a freelance writer and author who specializes in training professional working dogs. She is widely published in a variety of venues and actively competes in several canine sports. She also serves as a consultant for Service and working dog programs across North America and Europe.
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