How much protein should you feed Dubia roaches? This is the topic of passionate yet friendly debate among herp owners and roach-keepers. Some believe more is better, so they feed their roaches as much protein as they can fit into their diet. Others look at what Dubia roaches eat in the wild and conclude they are meant to eat very little protein. Those in the middle select a protein target somewhere between 20% and 50% and try to hit it with a mix of foods and custom-made roach chows. While the beliefs that drive these strategies differ, everyone in this debate shares one thing: They want to create the healthiest roaches possible through nutrition.
This approach makes sense. People buy Dubia roaches as alternative feeders at least in part because they’re so healthy. Dubia roaches attract people who want the best for their animals. Nutrition is a big part of their growing popularity. One thing they have going for them is that they’re high in protein, so it seems somewhat ironic that high protein in their diet can not only harm them, but actually kill them. And as it turns out, the same process that leads to their early demise on a protein-excessive diet may not be healthy for the animals that eat them.
Uric acid is a natural byproduct of protein digestion. It’s an antioxidant, and all animals need it small amounts. However, uric acid can be toxic if it builds up to very high levels in the body.
Most animals excrete excess uric acid, but cockroaches are unique. In most of the species studied, researchers find that protein a roach consumes beyond its immediate needs is converted into uric acid, which is then stored in an organ called the “fat body”. The fat body functions as a roach’s energy reserve much the same way the liver does in mammals. When the roach doesn’t get enough protein from food in its environment, the uric acid is converted back into protein.
This is a useful – and in some cases critical ability in the wild. Cockroaches evolved eating a mix of low-protein plant matter in various stages of decomposition and high-protein microscopic fungi and bacteria and other animal-based foods. The ability to store protein as uric acid means roaches can not only meet current protein needs with a high-protein meal, but they can meet their future protein needs as well. With this strategy, an occasional encounter with a dead animal in the rain forest is all they need to ensure their survival and the survival of their offspring. This is part of why cockroaches are considered such highly successful scavengers.
However, this uric acid adaptation is unnecessary in captivity where protein is not scarce. It can even be a liability in cases where well-meaning caretakers provide excessive protein in the diet. As mentioned, cockroaches aren’t equipped to handle this, and research demonstrates that there are negative health consequences. For example, a 65% protein diet can kill adult German cockroaches in just 16 days.
The following image from a study on nitrogen consumption of German cockroaches (external link) shows a linear, dose-dependent relationship between dietary nitrogen intake and uric acid stores.
And another study (external link) claims a linear, dose-dependent relationship between uric acid stores and mortality. This confirms that some cockroaches have no uric acid regulating ability, and that they just keep storing up more and more until they die. This conclusion is consistent across different data. For example, roaches consuming the lowest amount of protein tend to live longest while those consuming the most protein live the shortest.
Now, there are some cockroaches that regulate uric acid by excreting “pellets” that they can store for future use. In those species, males may even “trade” these pellets for female mating favors. While this underscores the importance of protein in the cockroach diet and its scarcity in the wild, this trading behavior has only been observed in a small number of cockroach species in which uric acid has been studied. There’s no evidence to suggest Dubia roaches have this ability.
The unregulated storage of protein in a form that can cause harm to the roach may indicate the high importance of the nutrient. And in fact, roaches can and do put it to use. As much as 90% (external link) of a roach’s uric acid stores may be used for ootheca (egg sack) production, which makes protein accumulation a primary reproductive strategy.
So you might ask: Why is this a problem? Most consumers feed off the roaches they buy within a week or two. And the 65% protein diet that kills German cockroaches is so high it’s almost impossible to achieve. Maybe 65% protein is bad for roach health, but they do just fine on 40%. And if so, while 40% is much lower than 65% it is still unnaturally “high”. Isn’t more protein good for the insectivorous animals these roaches are fed to? Aren’t they supposed to eat a lot of protein? Who cares about the health of a roach we intend to feed to our animals? Wouldn’t that just be silly and ironic?
While these questions are reasonable, the answers are not quite so simple. Uric acid itself is not a protein. The roaches rely on specialized bacteria that live in their bodies to handle the conversion. To all us non-roaches, uric acid is a well-regulated waste product that is excreted in the urine. It seems the cockroach is unique in its strategy of storing it for future use. The bottom line is that they adapted to scarcity, not to abundance, and we have to be careful what we feed them. And this makes sense. “More” is not always better for the world’s most successful scavenger.
What does this mean for consumers?
Fortunately, there is some good news. Uric acid consumption in the doses we’re talking about doesn’t itself cause disease. Healthy animals don’t have problems dealing with it, and its toxicity is low (Hamilton, 1988). And, there are a lot of people feeding Dubia roaches very high protein diets without reports of gout, kidney stones, or other uric acid-related problems in captive herps. The popularity of Dubia roaches has risen in recent years, but there has not been an increase in hyperuricemia or related problems. If there were to be damage from uric acid, it would become known in the pet trade, and this has not happened.
There are also other reasons why the uric acid issue is of low concern. Since roaches accumulate uric acid over time, adults have more than nymphs. The younger the roach the smaller the uric acid stores. In fact, it appears that all the studies associating high protein diets to roach mortality were done with adults.
In the Dubia roach business, nymphs are typically feeders while adults are kept for breeding. The first quarter of a Dubia roach’s life is lived as a nymph and the remaining 75% as an adult. This is not to say that feeding adults to animals is necessarily risky, but rather that whatever the ultimate risk may be, nymphs are considerably less risky than adults in relative terms. In fact, nymphs are driven to consume protein foods to build their stores in anticipation of future breeding. That is their only job as nymphs.
And we have data comparing nymphs to adults. As expected, it suggests nymphs have far less accumulated uric acid. In one study, adults had 20 times more uric acid than nymphs (external link). This makes sense. Not only have nymphs not had the time to accumulate excess protein and uric acid as mentioned above, but they also use relatively more of it to fuel their rapid growth. In short, they eat more protein but they use more too.
There is also research showing that different species hold onto different amounts of uric acid (external link), and the amounts vary widely. For the record, none of the uric acid research looks directly at Dubia roaches. We don’t know where on the scale they fall with respect to uric acid accumulation. We only know amounts vary by species.
In light of all this data, we think the roach/uric acid issue is probably not a particularly pressing one for the average consumer. It seems that excess uric acid is only a theoretical issue at this point. We aren’t aware of any adverse effects of feeding roaches to reptiles, amphibians, or arachnids.
However, some herps may be more vulnerable to the effects of uric acid than others. Those with existing renal disease come to mind. The existence of arthritic conditions or kidney impairment may benefit from a diet low in uric acid. Again though, this is theoretical. If your animal has any health issues, you should probably get dietary advice from a veterinarian.
If you’re concerned about excess uric acid in your animal’s diet, there are a few steps you can take to lessen the potential load. They can be done either alone or in combination.
Don’t feed roaches casein
In addition to testing very large doses of protein (typically 40% and above), studies suggest protein from casein has more than twice the uric acid boosting power of other proteins. A study by Mullins and Cochran compared a high non-casein protein diet to equivalent protein (external link) as well as higher casein protein diets. The 25% non-casein protein diet raised uric acid half as much as the 25% casein protein diet. And, the more casein the higher the uric acid. The takeaway is that if you’re concerned about gout, don’t feed your roaches protein made from milk.
Target a “reasonable” protein level
Since uric acid accumulation is linear and dose-dependent, choose a protein level you think will have the best effects on the roaches with the least uric acid build-up. Then try to hit it. This is easy enough for those who mix their own roach chow. Food ingredient nutrition information is widely available online, as are tutorials on calculating caloric density, figuring nutrient percentages, and combining ingredients. Spreadsheets with a few simple formulas can be helpful for working out these numbers. It’s just a matter of getting them set up and then plugging in the protein, carb, and fat information for each feed ingredient.
So what protein level should you target? This is a key question, and other studies give us clues about the dietary protein needs of roaches. A study by Hamilton et. al. (external link) uses the Brown-banded cockroach ( Supela longipalpa ) as a model for cockroach reproduction and longevity. They tested females reared on 23% protein rat chow and then at adulthood, placed on either a 5% protein, 23% protein, 25% casein protein, or 65% casein protein diet. Of almost all the metrics they tested, roaches in the 25% protein group performed the best.
On the other hand, roaches on the 5% and 65% diet did poorly. Actually, the ones eating 65% protein did really poorly. The study’s author even suggests that too much protein is “toxic to female S. longipalpa” and notes that they died in 26 days with only one female mating and then dying 17 days later. On the other side of the spectrum, the cockroaches eating 5% protein were long-lived but their rate of reproduction was very poor compared to roaches eating protein in the mid-ranges. If you want a long-lived roach that grows slowly and does not reproduce, a very low protein diet is the way to go. Otherwise, both the high and low protein diets should be avoided.
While we don’t know exactly how much dietary protein is “ideal”, we know roaches eating 23% protein diets reproduce “normally” and live what researchers consider a normal lifespan. Of the four protein levels tested (5%, 23%, 25%, and 65%), 25% performed best. We also know from another study that when given the option, Brown-banded cockroach nymphs choose a diet of 25:75 protein to carbohydrate (Cohen, 1987). So at this point we have some good information. 25% protein seems like a reasonable “ideal” to target.
Nutritional needs depend on life stage
As we close in on a solution to the excess protein issue, another albeit smaller issue comes up. It seems roaches differ in their nutritional needs (external link) depending on life stage, environment, and breeding situation. Nymphs, for example, need relatively high protein – but only during certain stages of development. Females need higher protein at different times too, but their needs are related to egg development and other reproductive processes. Other times they eat very little protein. Adult males need protein, of course, but they tend to prefer carbohydrates much of the time. This too is due to their own physical processes related to growth and mating.
Importantly, when roaches don’t get the nutritional support they need, their growth and reproduction suffers. We’ve seen it happen, and it doesn’t take much to throw them off-track. Nymphs deprived of adequate nutrition fail to grow or grow more slowly. Adult females with poor diets reproduce less and have fewer offspring that are themselves nutrient deficient, which leads to high mortality.
This issue may not matter to you if you’re keeping roaches as feeders. However, survival, growth, vitality, and productivity are important if you’re breeding B. dubia, and nutritional deficiencies have such a powerful impact on their health that their results can be seen with the naked eye.
The question that needs to be answered is how do we get the right combination of nutrients to each individual roach in a diverse colony at the right time based on each individual insect’s widely varying nutritional needs? We could split them up by age and sex and then feed them what they need, but that means we have to know exactly what they need. Unfortunately the nutritional research is not that precise.
Feeding different foods to a colony with a diversity of roaches borders on impossible. And it probably is impossible. However, it doesn’t matter because it turns out that roaches self-select for nutrition. That is to say, they eat what they need when they need it. Of course, this works only if they have access to the right foods. This is where the solution lies.
Dubia roaches do a very good job of eating foods with the nutrients they need when they need them, and avoiding the ones they don’t. Young Dubia roach nymphs eat poop – presumably because it is very high in nitrogen and contains the cellulose-digesting and protein-producing bacteria that colonize their guts and allow them to survive. Females will eat high protein in anticipation of developing young, and then feed heavily on carbohydrates when their biology demands it. Males prefer fruits, vegetables, and other carbs during reproduction but high protein during development. Nymphs will eat more protein at the beginning of their instar then gradually increase their carbohydrate intake until their next molt, at which time they switch back to protein.
The truth is that Dubia roach dietary strategies are probably much more complex than this, every insect has the ability to select foods based on need, and all we need to do is make sure they have access to nutrients.
This is quite an efficient system. Given other options, cockroaches won’t eat so much protein that it compromises their health. And this is key in our excess protein/uric acid issue. Given the chance, Dubia roaches will eat what they need. They go for what is best for them in the moment and they leave the rest behind. They won’t eat themselves to death with too much protein if they have access to food without high protein. Pretty simple.
However, for this to work, food must be in a form that the roaches can recognize. They need to be able to choose to eat a particular food ingredient or discard it. They can’t do this if their food is blended into a fine powder. When food with incorrect levels of macronutrients and then blended finely, the ability for self-selection is lost and roaches have no choice but to eat the combined mixture. When that happens they are at the mercy of whatever the combination of ingredients happens to be. Any nutritional deficiency that exist in the mixture will be passed along to them.
The solution is to either provide ingredients in raw, un-blended form or provide some degree of separation of carbohydrates and cellulose-centric foods and protein heavy foods. Nymphs have an ability to accurately regulate protein intake (external link), and this is consistent with our experience.
A word of caution
At this point we want to make a recommendation to Dubia roach breeders and explain its reasoning. If you’re just feeding them off to your animals you can probably skip this section.
The foundation of our own Dubia roach diet is a combination of two roach chow blends. One is protein-centric and the other is carb-centric. We provide both simultaneously, and our roaches choose between the two. Some ingredients are safe to blend fine or semi-fine, but some are best left in pieces large enough for roaches to choose them or reject them based on the dietary self-selection concept explained above.
Although we blend some of our dry ingredients, we strongly recommend that you don’t. Here’s why:
We developed our roach chow and our approach to feeding over a long period of time. Our formula contains ingredients in very deliberate proportions that were chosen after a lot of testing and experimentation. Along the way, many ingredients that seemed well-reasoned and logical did not work as we had thought or hoped. On the other hand, some ingredients worked better than we imagined.
Of course, we think the best solution is using our roach chow. It is highly developed and appropriate for every stage of development and every purpose. Whether you’re keeping nymphs or adults…feeders or breeders…it has all the nutrition they need for each stage of their development. However, if you blend your own roach chow, we recommend erring on the side of caution and providing un-blended or coarsely-ground ingredients. If your roaches dislike an ingredient or don’t need it, they can avoid it with a coarse grind. If you include just one ingredient they dislike – and there are many – in a finely-blended powder, they may eat less overall and get less of what they need. Or, if the mix is deficient in a nutrient, they may overeat, which after reading this article you will recognize as undesirable.
This is important. We constantly test ingredients, and new additions routinely disrupt consumption. One thing we know for certain is that we never know what will happen with new ingredients until we test them. Though we’ve gotten better at predicting results, that has only come with experience.
Restrict dietary protein before feeding
Another strategy to reduce uric acid if you’re concerned is to go low-protein. Dubia roaches mobilize and deplete uric acid stores when dietary protein is low. If you’re so inclined, you can buy a bunch of dubia roaches, put them on a very low protein diet, and feed them off as you go. A 5% protein diet or less mobilizes uric acid. This gives roaches time to use up some of their stores. Mullins and Cochran tested cockroach uric acid excretion (external link) by feeding a group of American cockroaches a very high (40%) protein diet and then switching them to a very low (0%) protein diet and observing how fast they used up uric acid stores.
You can see that uric acid levels began falling right away and they continued falling as long as dietary protein stayed low.
Go easy on the protein and take breaks from gut loading
Insectivores need protein, but it’s possible to go overboard. You probably don’t need to gutload insects with extra protein before feeding them to your animals. It’s sufficient to feed herps one or two primary insects while throwing in a few different species on occasion for variety. If you want to reduce the chance of gout, the best thing you can do is make sure your animals are properly hydrated. As long as the uric acid they ingest is eliminated there is no issue, and water is how herps do that.
Gut loading is an effective way to deliver targeted nutrition to captive herps, but as with many things in life, more is not always better. Calcium is a classic example, and vitamin A in its pure form can also be toxic. It seems that protein too may also have potential for overload hazard among captive herps. In each of these cases, moderation is key. You don’t want to just simply pile on the protein same as you don’t want to load up on calcium or vitamin A.
This brings up a key concept regarding herps and uric acid. It’s not uric acid per se that’s a problem. It’s excess uric acid that’s the problem. Healthy animals can deal with dietary uric acid. It doesn’t cause disease. In fact, it’s technically an antioxidant. It only builds up in animals that are already suffering from kidney-related problems. And in cockroaches, of course, but the point is that avoiding uric acid isn’t necessary in most cases.
The Bottom Line
So who has the best answer to the question of how much protein to feed Dubia roaches? The answer is that it may depend on what you want your roaches for.
If it’s breeding, the scientific literature aligns itself with those who say around 25% protein is best. But the data is limited to adults. No diet studies comparing protein intakes to growth have been done on nymphs, and we know that Dubia roach nutritional requirements vary significantly according to life stage. This seems to be an argument for our self-selection strategy of providing a “base” chow with a lower level of either protein or carbohydrates, then supplementing with a separately-offered food on the side containing a lot of the nutrient depleted in the chow. We know with certainty that not all food is right for all Dubia roaches all the time. The trick is to get the nutrients they need to them when they need them.
If it’s feeding, there are several options not available for those interested in breeding. Longevity is enhanced and uric acid stores are used up on a very low protein diet. While there is no evidence that it’s necessary, one could feed their feeder roaches a very low protein diet without compromising their nutritional value, and possibly even enhancing it.
The uric acid issue seems to have a very low potential to create problems in captive herps. We aren’t aware of any gout or kidney issues caused by roach consumption, but in theory the potential exists. For animals with reduced capacity for elimination it might be wise to lower or cut Dubia roaches from the diet. If animals are health and the consumer still wants to reduce uric acid and/or protein, there are multiple solutions available. These include a very low protein maintenance diet, a self-selection diet, a no-casein diet, a change in gut loading strategy, and finally…
not trying to pack more and more protein into feeder insects with the belief that more is always better. Insectivores, for example, need 30% to 50% dietary protein while omnivorous reptiles need 20% to 25%. Dubia roaches contain plenty of protein to meet both of these needs with room to spare. There isn’t a need to pack on more. Doing that may even have the potential to cause problems.
While it’s good for people like us who produce Dubia roaches commercially to take precautions, in the end this may be unnecessary for consumers. There probably will never be any Dubia roach-induced hyperuricemia issues, and the best use of this information is for owners of animals with existing renal disease who should probably steer clear of Dubia and other roaches as feeders.
Sources and References:
Cohen, R. W., et. al. (1987). Nutrient self-selection by the omnivorous cockroach Supella longipalpa.Journal of Insect Physiology, 33(2), 77-82.
Hamilton, R. L., & Schal, C. (1988). Effects of dietary protein levels on reproduction and food consumption in the German cockroach (Dictyoptera: Blattellidae). Annals of the Entomological Society of America, 81(6), 969-976.
Haydak, M. H. (1953). Influence of the protein level of the diet on the longevity of cockroaches. Annals of the Entomological Society of America, 46(4), 547-560.
Jones, S. A., & Raubenheimer, D. A. V. I. D. (1999, July). An integrated approach to baiting strategies for the German cockroach, Blattella germanica (L.)(Dictyoptera: Blattellidae). In Proceedings of the Third International Conference on Urban Pests, Prague, Czech Republic (pp. 19-22).
Kells, S. A., et. al. (1999). Estimating nutritional status of German cockroaches, Blattella germanica(L.)(Dictyoptera: Blattellidae), in the field. Journal of insect physiology, 45(8), 709-717.
Mullins, D. E., & Cochran, D. G. (1976). A comparative study of nitrogen excretion in twenty-three cockroach species. Comparative Biochemistry and Physiology Part A: Physiology, 53(4), 393-399.
Mullins, D. E., & Cochran, D. G. (1975). Nitrogen metabolism in the American cockroach—I. An examination of positive nitrogen balance with respect to uric acid stores. Comparative Biochemistry and Physiology Part A: Physiology,50(3), 489-500.