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Basic roach care/diet information from a 50 year biohemist/roach researcher


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For everybody wondering about the e-mails I've sent with the professor (who is also a biochemist) who has been posting research on roaches since 1966, I will copy those below.  Granted, there are over 4,800 species of roaches and no single person has researched them all to any great degree, so take away what you will from the questions and answers below.  I personally have a small breeder colony that I've had less than two months, so I am not an authority on roaches of any species.  I'm simply a technical person by nature that has a touch of self-diagnosed OCD who found so many websites with conflicting information that I decided that I wanted to ask someone that I felt would know roaches better than 99.9% of the people posting information on forums. 

My apologies to anybody I may have misquoted in my questions to the professor.

The text in gray are my questions, and the professor's answers are below in black.

Question: I have a bearded dragon that I feed Dubia roaches to as a feeder insect, although I am enjoying raising a colony of Dubia as much as my bearded dragon.  I may also start raisin Orange Head roaches or others in the future. 

Question: I'm assuming that most roaches have similar nutritional needs as far as protein and other requirements.  Is this true?


Yes.  All cockroaches have symbiotic bacteria living in their fat body which synthesize most of what are vitamins for vertebrates, since they cannot produce them themselves.  The cockroach can eat a very un-nutritious diet and thrive.  The cockroach is also very economical with nitrogen.  They can store excess nitrogen (rather than excrete it) as uric acid in their fat body in cells called urate-cells.  This urate can be metabolized by the bacteria and turned back into protein nitrogen for use in protein structures.  They can thus survive when they are provided with low nitrogen food.

 Also, Repashy.com had quoted you on their site (based on making their 'Bug Burger' better for roaches) as saying “My initial reading of your composition is that it has too much protein (>20%). 4% protein is sufficient to support Blattella germanica and if it is >20% they will accumulate waste uric acid in their fat body which could be lethal in certain situations.” Joe

That seems to be an accurate transcription of what I have told, whoever asked me about needed protein content of a roach diet.

 What would you recommend for feeding a colony of Dubia roaches or Orange Head roaches to keep them healthy without providing too much nitrogen/protein?  I know nymphs need more protein as they grow, and adults need less after reaching full size, so is there a happy medium, or if I feed two food sources, one with high protein and one with low protein, will the roaches feed off of the correct food source to level out their proper protein requirements?  I want to both feed my bearded dragon healthy food, and I want to keep my colony as healthy as possible.

The 4% protein diet should satisfy all stages.  You can produce some happy medium with a minimum of work by allowing them to choose their own diet but forcing them to get some of their moisture from vegetables such as carrots and potatoes that provide more filler that is low in protein and provide a restricted amount of the ~20% protein from readily available dog/rat chow.

I apologize for the length of this e-mail, but there are so many people stating incorrect information that I don't know what to trust.  Also, what is the protein content of a roach?  I've seen people state anywhere from 20% to 65% protein.

I have no idea.  That is not a basis on which I make any decision and have never measured it for any of my projects.  The protein in their hemolymph varies tremendously and I have published on that in several species.


What does healthy roach scat/frass look like?  A dark brown such as this?

This picture is not high resolution enough for me to recognize it as roach scats.   Here is a URL to Periplaneta americana scats from a culture that had restricted water so that their scats are relatively dry … but the animals are still healthy.  Gorse seed is interspersed with the scats as a size standard.


Roach scats can vary tremendously depending upon their water availability.  Lots of water makes messy scats and a polluted cage.  I usually provide water in tubes with a cotton plug.  Also I provide a clean environment for them to eat, drink and grow such as shown here:



In my research lab I vacuumed out scats and food debris on a regular basis.   The above dish could hold up to a hundred 6th instar Blattella germanica.  Your Dubia roaches are larger and would be reared in shoebox or blanket box containers depending on stage.  I would adjust their food and vegetable and water access to avoid them fouling their containers.  A good balanced nutrition will produce healthy cockroaches that will be healthy food for your lizards.

I do not necessarily suggest spending all the effort I have made to produce research grade synchronized cultures of cockroaches but, when rearing the easy way in mass cultures, it is hard to maintain a uniform healthy culture.   It would not be my way.

(2nd e-mail)

Question: You said, "The cockroach can eat a very un-nutritious diet and thrive."  In the long run, considering breeding colony health and the health of the roaches fed to the bearded dragon and its health, do the items put into commercial roach chow do anything to increase roach health, reproductive virility, speed of nymph growth, etc.?  Items such as bee pollen, spirulina, chlorella and strawberries, various vitamins, or is it mostly just sales fluff in your opinion?  Or is the old adage true as well for roaches, “You are what you eat”?


I am not aware of commercial roach chow.  If I were rearing large numbers of roaches I would follow my research results as I explained in my last mail … aiming at a 4% protein diet and provide occasional fruit.  I actually ate bananas myself and put the peals in the large tropical roach blanket containers.

 Does it matter what the source of nitrogen/protein is for roaches?

No.  The cheapest and easiest to store free of pests would be my choice.   I had an animal facility from which I obtained Purina rat chow essentially for free.  It was 18% protein and I pulverized it and cut that down to 4% protein with potato or corn starch and compressed it into tubes.  That much work might not be worth the effort as I suggested earlier.

 One gentleman on the forums is saying plant based protein is safe for roaches and protein derived from purines is more harmful and causes the higher uric acid/urate content which can cause gout in bearded dragons.

I am trained as a biochemist and I have never heard or read the idea "protein derived from purines”.  Proteins are composed of amino acids.  Purines are one of the base types in nucleic acids DNA and RNA which are minor components of most foods.  Uric acid is a purine as well as guanine which are well known nitrogenous wastes of insects and spiders.  I am not sure where you would find a natural food that is totally free of purines.  Vertebrate proteins (meat and organs) are higher in nucleic acids but one would not likely feed your roaches expensive vertebrate meat or organs.  Plants are cheaper and in general lower in both protein and nucleic acids.   Again, my focus would be in lowering the protein content of the food to 4-5% and let the other minor food components decrease in the same proportion as the dilution.  A plant based meal such as oatmeal would be a good base.  Raw oats are 17% protein and are the basis of many animal chows.  Most plant protein, e.g. oat protein, is lysine poor.  That is why being a vegetarian is a problem … humans are omnivores by evolution and we get our lysine from eating at least some animal protein.   However, the bacteroids in cockroach fat bodies produce lysine so oatmeal is a fine source of protein for cockroaches.  Serious herbivores have an active appendix in which the bacteria also produce lysine for the herbivore.

   Or is it simply the amount of nitrogen/protein, no matter the source?


 You said you vacuumed out the scat and food debris on a regular basis.  Do you mean every few days?  There are people on the forums, as well as established website companies selling feeder roaches that have had breeding colony’s for years that say not to clean the scat but once every 3 months or so, where another has said to let the scat accumulate until it is about 3 inches deep as the nymphs burrow in it and eat the undigested food particles out of the scat.

In general I did not raise in mass cultures.  You and your friends should trust your experience of what works for you.

 Several forum members swear “oranges” make the roaches reproduce faster or give birth to a higher number of nymphs.  Does this make sense?

I am not sure what that would be related to.  Nobel Prize winner Linus Pauling swore we should all be eating mega-vitamins and particularly Vitamin-C.  He died at 93.

   Is mold really that harmful to roaches?

Roaches harbor numerous molds with no ill effects.  There are molds which will actually kill cockroaches.  I sent my two sons through college based on profits from selling high grade synchronous cockroaches to a company EcoScience which was developing a mold based cockroach trap that was very effective and worked on the basis of attracting roaches to eat a bait laced with a mold spore that they would carry and transmit to fellow roaches killing all the roaches in a building and providing spores that kept the roach population down for as long as the spores survived.  So, beware bad mold.  Your mold likely came from your supplier’s culture and thankfully was not a danger to your culture. There are many thousands of innocuous mold species.


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Also, some general FAQ's that I found interesting.


A few questions I enjoyed:
6.Why do cockroaches die on their backs?
7.Do cockroaches bite?
12.Are cockroaches really clean?
39.How do Cockroaches Digest and what organs do they use to do so?
56.How fast are cockroaches?
68.Color cockroaches most attracted to?
79.Can female-only set of hissing cockroaches give birth 7 months after purchase?

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Great resource!

However, there's one clue that he's a biochemist, but not a nutritionist:


Most plant protein, e.g. oat protein, is lysine poor.  That is why being a vegetarian is a problem … humans are omnivores by evolution and we get our lysine from eating at least some animal protein.

Eating oats would provide plenty of lysine, but perhaps be poor in some other amino acid available in other plant sources. There are several good plants source of lysine, notably beans. But yes, diets lacking higher plant sources of lysine would be detrimental to humans.


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I would like to add something....I recommend not using poultry crumbles/pellets in your dry roach chow. One ingredient found in most if not all poultry feed products, even those labeled "organic" is Methionine. Methionine is an amino acid protein found in many natural food products, much needed in humans and I assume most mammals, birds, and who knows what else.  For poultry producers wishing to breed faster growing birds, they discovered that Methionine was a "limiting" amino acid protein....the weakest link in the chain if you will. They needed to raise this limiting factor and over the last several decades a synthetic form of Methionine was developed. This synthetic form was known as DL-Methionine. They discovered another wonderful attribute of DL-Methionine, that being it was an effective insecticide for pest insects with an alkaline gut physiology....pests like mosquitoes and termites....and yes, many cockroaches...if not all...have this alkaline gut physiology. I have purchased bags of both poultry feed and wild game bird feed at reputable feed stores where the ingredient list clearly notes DL-Methionine, while others...even some claiming to be organic....clearly had Methionine in their nutrient lists. (nothing wrong with that given Methionine's "natural" origins - DL Methionine is the synthetic version) Those with just the word Methionine in their nutrient list, not DL-Methionine - also had the term "Methionine Supplement" in their ingredient list. I was confused...what the heck is a Methionine supplement ? 

It would appear that the Association of American Feed Control Officials (AAFCO) set the standard of identity for DL-Methionine (a known insecticide) as containing a minimum of 99% racemic 2-amino-4-methylthiobutryric acid. (AAFCO 2001)   I have no idea what that means....BUT....The AAFCO model regulation states that "the term Methionine Supplement may be used in the ingredient list on a feed tag to indicate the addition of DL-Methionine."  Imagine, you are trying to grow roaches or poultry using organic means, and a product which claims to be organic, and even claims their product is "insecticide free", has the term Methionine Supplement in its ingredient list...a term not commonly associated with an insecticide like its cousin DL-Methionine.

I can provide links and pictures of ingredient tags on several different products if necessary. I encourage any interested parties do their own research on Methionine and DL Methionine. Read about the effect the insecticide has on mosquito larvae, affect on early instars and lack of effect on older bugs. Read about "Juvenile Hormone Inhibitors" (JHIs) and the need for more "natural" insecticides all over the world. If you are struggling to find out reasons for mysterious deaths of newborn nymphs, smaller than normal female breeders, early deaths of breeders, or any other issues without easily understood red flags that need to be addressed....look at the ingredient lists of the products you are using in your foods....even those labeled organic. You might be surprised to learn you are introducing an insecticide into your roach bins....I know I was.  Mike

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