Just like reptiles, feeder insects have their own nutritional needs. When those needs aren’t met, they become unhealthy. While you may not be keeping these insects as pets, it’s still important to pay attention to their nutrition, because what you feed to them eventually gets passed on to the reptile that eats them. Today we’re going to take a look at the role of protein in the diets of feeder insects.
Effects of Too Little Dietary Protein
Protein plays two main roles for feeder insects: 1) it facilitates growth, and 2) it helps them reproduce successfully. When feeder insects don’t get enough protein in their diet, it stunts their growth, and crickets will outright die when they don’t get enough protein. If you are trying to start your own colony of feeder insects, not giving them enough protein is likely to reduce the number of offspring they can produce.
As a general note, if you’re not trying to breed your own feeder insects, it’s hard to provide too little dietary protein unless you’re not feeding them at all. Starvation is, of course, not a good practice when you’re trying to create the most nutritious feeders possible for your pet.
Effects of Too Much Dietary Protein
Of course, loading on the protein isn’t good for them, either. Even for insects that have higher dietary protein needs, like crickets, increased protein in the diet doesn’t necessarily make them healthier. For example, roaches fed on a 65% casein protein diet experience an alarmingly high mortality rate after reaching adulthood. A higher-protein diet may also actually decrease disease resistance in adults.
Finding “Just Right”
The ideal amount of protein for feeder insects is going to be enough to allow them to develop healthily and at a normal pace, but not so much that they suffer as adults, or that their protein content can potentially pose a danger to the reptile or amphibian that is eating them. This number will change depending on the feeder in question. For example, 4% protein is enough to support Blattella germanica, and protein levels greater than 20% will cause potentially lethal uric acid accumulation. According to Allen Repashy, the ideal feeder insect gutload is 15% protein or less. Even crickets, which have higher protein needs than most, will still do just fine at 12% protein.
Of course, a well-hydrated, healthy reptile/amphibian shouldn’t have any problem regardless of the insects’ protein content in theory, but gutloading your feeders mindfully is a good way to mitigate risk.
What to Feed Your Feeder Insects
All feeder insects that are commonly used as routine feeders (crickets, locusts, grasshoppers, roaches, black soldier fly larvae, hornworms, silkworms, mealworms, superworms, fruit flies) are primarily herbivorous, which means that they naturally have a plant-based diet. This can be grain or vegetation, but keep in mind that grain brans are high in phytic acid, which inhibits the absorption of minerals such as calcium, magnesium, iron, zinc.
What many people do is simply keep their feeders supplied with cheap fresh fruits and vegetables such as carrots, potatoes, apples, and oranges. These usually work well enough to keep the insects alive long enough to be fed and make sure they have adequate hydration and some extra vitamins. However, these foods are not well-balanced standalones, which means that they can potentially lead to nutrient deficiency in the reptile that ultimately eats those insects.
It’s ideal to gutload your feeder insects with nutrient-dense diets that are specifically formulated to maximize their health and nutrition value. Examples of good, proven diets include:
- Dubia.com Dubia Diet
- Dubia.com Hornworm Food
- Repashy Bug Burger
- Repashy SuperHorn
- Repashy SuperFly
- Arcadia InsectFuel
What Not to Feed Your Feeder Insects
Because most feeder insects are primarily herbivorous and it’s best practice to use lower-protein diets, it’s best to avoid any animal-based diets. For example, these are some commonly-used insect foods that should be avoided as gutloads:
- Dog food
- Cat food
- Fish flakes
- Chicken feed
- Rejected snake prey carcasses
When in doubt, look at the ingredients list. If you see animal by-products or large quantities of grain bran on the list, look for something else. Casein should also be avoided, as this substance is known to result in significantly higher uric acid levels in roaches.
Conclusion
Protein is an important macronutrient that is critical to the growth and long-term wellness of feeder insects. But it’s also important to remember that too much is just as harmful as too little. Even though you’re just going to end up feeding these bugs to your pet reptile or amphibian, what you feed to them is what you eventually feed to your pet.
Part of responsible reptile/amphibian care is paying attention to their nutrition. Gutload your feeder insects mindfully, and you will be rewarded with a healthier pet.
References:
Are anti-nutrients harmful? | The Nutrition Source | Harvard T.H. Chan School of Public Health. (2019, January 24). The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/anti-nutrients/
Bawa, M., Songsermpong, S., Kaewtapee, C., & Chanput, W. (2020). Effect of Diet on the Growth Performance, Feed Conversion, and Nutrient Content of the House Cricket. Journal of Insect Science, 2. https://doi.org/10.1093/jisesa/ieaa014
Córdoba-Aguilar, A., Nava-Sánchez, A., González-Tokman, D.M. et al. Immune Priming, Fat Reserves, Muscle Mass and Body Weight of the House Cricket is Affected by Diet Composition. Neotrop Entomol 45, 404–410 (2016). https://doi.org/10.1007/s13744-016-0391-0
Dubia roaches and dietary protein: How much is enough? (2014, July 3). Dubia Roach Depot. https://dubiaroachdepot.com/guidance/dubia-roaches-dietary-protein
Kelly, C. D., & Tawes, B. R. (2013). Sex-Specific Effect of Juvenile Diet on Adult Disease Resistance in a Field Cricket. PLoS ONE, 4, e61301. https://doi.org/10.1371/journal.pone.0061301
Le Gall, M., & Behmer, S. T. (2014). Effects of Protein and Carbohydrate on an Insect Herbivore: The Vista from a Fitness Landscape. Integrative and Comparative Biology, 5, 942–954. https://doi.org/10.1093/icb/icu102
Liu, C., Masri, J., Perez, V., Maya, C., & Zhao, J. (2020). Growth Performance and Nutrient Composition of Mealworms (Tenebrio Molitor) Fed on Fresh Plant Materials-Supplemented Diets. Foods, 2, 151. https://doi.org/10.3390/foods9020151
Repashy, A. (n.d.). Can Feeder Insect Diets Contribute To Gout In Reptiles? Repashy Ventures. Retrieved December 17, 2021, from https://www.store.repashy.com/can-feeder-insect-diets-contribute-to-gout-in-reptiles.html
Royauté, R., & Dochtermann, N. A. (2016). When the mean no longer matters: developmental diet affects behavioral variation but not population averages in the house cricket (Acheta domesticus). Behavioral Ecology, 1, 337–345. https://doi.org/10.1093/beheco/arw164
