Author: allen (Page 3 of 3)

Happy 57th Anniversary, Wheat Germ in Insect Diets!

Wheat germ from two different sources: which one is best for your diet?

Wheat germ from two different sources: which one is best for your diet?

The power of wheat germ as a diet component: a revolutionary breakthrough!

There is no way to express the magnitude of influence that the introduction of wheat germ has had in the science of entomology and in related disciplines.  There have been huge scientific, economic, ecological, and social impacts from this remarkable innovation since its introduction more than 57 years ago.   More than 1000 citations of the rearing paper on Manduca sexta (the tobacco hornworm) have been made for this paper: Bell, R. A. and F. G. Joachim.  1976.  Techniques for rearing laboratory colonies of tobacco hornworms and pink bollworms (Lepidoptera-Sphingidae-Gelechiidae). Ann Entomol. Soc. Am. 69: 2:  365-373 and nearly 300 more citations refer to the original M. sexta rearing paper from which the Bell and Joachim diet is derived (Yamamoto, R.  1969.  Mass rearing of the tobacco hornworm: II. Laval rearing and pupation.  J. Economic Entomol. 62: 1427-1431.  Besides these 1,300 references to the tobacco hornworm diet, there are thousands of other papers that refer to wheat germ as a principal component of diets for scores of other insects, and beyond the research/ scientific scope of wheat germ influence in insect diets, programs such as the pink bollworm sterile techniques program and many other mass-rearing programs depend hugely on wheat germ.  This would make the influence of the wheat germ diet have an impact of billions of dollars over the years since this deceptively simple-sounding advancement was made in 1959.

How did wheat germ get introduced into insect rearing?

The great USDA, ARS scientist, Dr. Erma S. Vanderzant (January 30, 1920-November 2, 1999) was a biochemist who worked at the College Station USDA Laboratory associated with Texas A&M University.  She had worked for years on diets for cotton insects, including boll weevils, pink bollworms, Lygus bugs (western tarnished plant bugs), and to a lesser extent, green lacewings.  She laid down many of the nutritional and biochemical fundamentals of these insects, and in my opinion, she never fully received the full credit for the amount of advancement that her meticulous and insightful studies had provided our community.

An inauspicious start for wheat germ!

In 1959, Dr. Vanderzant and her colleagues published a paper on feeding and oviposition of boll weevils (Vanderzant, E. S., C. D. Richardson, and T. B. Davich.  1959. Feeding and Oviposition by the Boll Weevil on Artificial Diets.  J. Econ. Entomol.  52: 1138-1142.)  In that paper, wheat germ was shown to be of unspectacular value in one of several diets, but it had one distinguishing quality: it served as an oviposition stimulus: something that had been problematic to the several researchers trying to mass-rear boll weevils without using host materials (cotton bolls or extracts from cotton bolls: it was the efforts that Robert T. Gast had made to extract cotton bolls that led to his untimely death resulting from an explosion of an autoclave during a solvent-based extraction process at the USDA, ARS boll weevil lab in Starkville, Mississippi).

But for some reason, Erma Vanderzant and some of her colleagues decided to try wheat germ in the diet of pink bollworms, another cotton pest that had proved elusive to development of really practical diets that would economically and reliably support development of multiple, continuous generations of “pinkies” for sterile release and other management programs.  The results of this work were published the year after the debut of wheat germ in this paper: Adkisson, P. L., E. S. Vanderzant, D. L. Bull, and W. E. Allison.  1960. A wheat germ medium for rearing the pink bollworm.  J. Econ. Entomol.  53: 759-762.  As the saying goes, “the rest is history.”  The application of wheat germ to “pinkie” diets was such an impressive success, that hundreds of other authors followed the teachings of Erma Vanderzant about the wonderful efficacy of wheat germ as a major component in insect diets.  In the nearly 60 years since the advent of wheat germ in insect diets, we have come to understand SOME of the properties of this material that makes it such a suitable diet factor, but there is much more that needs to be understood.

I strongly advocate the exploration of the reasons WHY wheat germ is so helpful to insect feeding efforts, and I will discuss some of these questions in near future postings on this site.

Now available: Insect Rearing Online Course!

An ideal course for people new to insect rearing or with limited experience.  This course is available as a NOT FOR CREDIT introduction to rearing, including the biological aspects and physical aspects of rearing systems.  You learn at your own pace, and you have access to the instructor, Dr. Allen Carson Cohen.  You get feedback from brief quizzes and from interactions with Allen Cohen.

Here are some details:

We are pleased to announce that our updated and improved online course in insect rearing is now open for registration.   The information about how to register and some highlights of the course is below.  Please note that among the changes from the online courses that we offered previously, we have everything in the introductory course included in one package, for which the registration fee is $400.00.  This fee gives you access for 12 weeks to all 66 course modules and supplements.  See our Course Outline page for further details.  All modules are followed by objective, self-graded quizzes, but students are invited (but not required) to write some short essay responses about course information.  We are sure that this course can be of great value both to people new to rearing and to experienced rearing personnel.  The format of PowerPoint presentations, narration (by Allen Carson Cohen), videos, and feedback from quizzes and email communication makes the course unique and a great value.

You may register for the online course one of the following two ways:

  1. You may Register Online
  2. Or you may Call to register. Please call Mr. Jeremy Watson to register  (919) 515-2261, (The Office Extension and Continuing Education) or you may call Jeremy directly at (919) 513-2161.  You may also email Jeremy Watson at jdwatso3@ncsu.edu

And, of course, if you are having problems or have questions, you can contact Allen Cohen (accohen@ncsu.edu).

Please see Current Online Course in Insect Rearing page

 

Pink Versus Yellow Vanderzant Vitamins

Vanderzant vitamins

Represented in the photograph are three samples of Vanderzant vitamins, A and B obtained from a different supplier, C being from the same batch as B but having been stored at room conditions for two weeks.  In neither product was the reference cited as to which mixture was being used, but the most widely used formulation is that of Vanderzant (1973), cited below.  The formulation of that mixture is provided in the table below.

However, it remains problematic for me to reconcile how two mixtures with identical names (“Vanderzant vitamins”) can be so dramatically different in appearance—one being obviously reddish-pink the other being conspicuously yellow!  I am refraining from citing the sources of the vitamins, but I must point out that in the formulations that I have published, I have always used the pink mixture (e.g. Cohen 2000, 2003, 2015), and recently I have become aware that the yellow version existed.  The pink to red color of the vitamin mix can be attributed to the color of vitamin B12, which contains the element cobalt.  Something that is not entirely clear to me is the basis of the red/pink/yellow colored alternatives, but it raises questions for me as to whether the two vitamin mixes are fully equivalent.

As a possible explanation for the color differences, please consider the following: there are several forms of what is called B12 or cobalamin and one of the alternately-used forms of B12 Cyanocobalamin is frequently used in vitamin supplements because of its superior stability over the simple cobalamin form. In an internet article about B12 ( https://en.wikipedia.org/wiki/Cyanocobalamin) it is mentioned that various reduced forms of Cyanocobalamin, with cobalt present as Co(I), Co(II), or Co(III) appear nearly colorless for Co(I), yellowish for Co(II) and pink for Co(III).

I have posted here two comparisons of profiles of formulations that I found in an internet search of the term, “Vanderzant vitamins.”  The 3rd formulation (not pictured here) represents itself as a modification, and two conspicuous differences are in the content of vitamin E or alpha-tocopherol and in the type of sugar used (sucrose, instead of glucose).  One further point that bears thinking is the faded appearance of sample C in Figure 1.  The vitamins in C are from the same batch as B, except that the materials in C were stored at room temperature and with light exposure for two weeks.  How much does the color change reflect deterioration of potency or quality of the vitamins?

The natural question raised by these conspicuous differences is how much can we rely on the equivalency of each formulation?  It is logical and reasonable to assume that any deviations from a prescribed, tested formulation can lead to differences in the performance of our target insects; and experience teaches us that very often differences often lead to harmful or undesirable results.  I frequently tell my students that any changes in the rearing setting may be 1) harmful, 2) helpful, or 3) neutral, and the only way to tell which way these changes will affect our target insects is by empirical tests—side-by-side controlled experiments with the questionable variable and the standard (control) form rigorously compared.

Here are the stated compositions of two mixtures called “Vanderzant vitamins:”

 

Table 1.Vanderzant Vitamin Mixture

Vitamin Amount (g/kg)
alpha-tocopherol 8
Ascorbic acid 270
Biotin 0.02
Calcium pantothenate 1
Choline chloride 50
Crystalline folic acid 0.25
Inositol 20
Niacinamide 1
Pyridoxine hydrochloride 0.25
Riboflavin 0.50
Thiamine hydrochloride 0.25
Vitamin B12 trituration in mannitol 2
Q.S. with glucose ~646.73

 

  • Q.S. (Latin quantum sufficit): literally as much as will suffice, used when adding a filler to a mixture to bring the weight or volume up to a prescribed level
  • Trituration: process of pulverizing a substance such as with a mortar and pestle, often used in diets as a means of mixing two or more solids such as a vitamin present in low concentrations with a sugar present in much higher concentrations

Vanderzant, E. S.  1973. Axenic rearing of larvae and adults of the boll weevils on defined diets: additional tests with amino acids and vitamins.  Ann. Entomol. Soc. Am.  66:  1184-1186.

Cohen, A. C.  2000.  New oligidic production diet for Lygus hesperus Knight and L. lineolaris (Palisot de Beauvois).  J. Entomol. Sci.  35: 301-310.

Cohen, A. C.  2003.  Artificial diet for arthropods (continuation in part).  U.S. Patent 6,506,597.  January 14, 2003.

Cohen, A. C. 2015.  Insect Diets: Science and Technology.  2nd Edition.  CRC Press.  Boca Raton, Fl.

Table 2.  Vanderzant formulation listed as “modified Vanderzant vitamins.”

Ingredient grams/kilogram
Sucrose 638.73
Vitamin E (500 IU/g) 16.00
Ascorbic Acid 270.00
Biotin 0.02
Calcium Pantothenate 1.00
Choline Chloride 50.00
Folic Acid 0.25
Inositol 20.00
Niacinamide 1.0
Pyridoxine HCl 0.25
Riboflavin 0.50
Thiamin HCl 0.25
Vitamin B12 (0.1%) 2.00

 

Comments about salt (mineral) mixtures

Comments about salt or mineral mixtures in insect diets (Beck salts, Wesson salts)

Rearing personnel use in their diets components that are specified in the literature, and quite often we use materials that have authors’ names associated with them (such as Wesson salts, Beck salts, Vanderzant vitamins, etc.)  I have been working on a diet for spotted lantern fly, which is reported to be a phloem sap feeder, and in keeping with this assumption, I wanted to use a derivation of the aphid diet reported by Mittler and Dadd (1962) with modifications by various authors from Stanley Beck’s laboratory, such as the paper by Retnakaran, A. and S. D. Beck. 1967.  Aspects of mineral nutrition of the pea aphid Acyrthosiphon pisum (Harris). J. Nutrition, 92: 43-52.  This paper provides a salt mixture that was used in experiments on pea aphid nutrition, and the authors concluded that an imbalance in the ratio of calcium and phosphate  caused failure of the aphids to grow and thrive.  I wanted to try a salt mixture widely reported on insect diets provided commercially as a salt/mineral mixture called “Beck salts.”  However, being aware of the importance of mineral characteristics, including concentrations and molecular species of salts, I was trying to get information from one of the suppliers who shall remain unnamed for this blog article.  I asked the supplier for the details about types of minerals and their concentrations, and I got a response that provided this list:

Beck Salt (Mineral) Mixture (I have withheld the supplier’s name for the sake of discretion).

Sodium Chloride

Ferrous Sulfate

Manganese Sulfate

Zinc Acetate

Cupric Sulfate

Calcium Phosphate, Tribasic

Calcium Phosphate, Monobasic

Potassium Phosphate, Dibasic

Potassium Phosphate, Monobasic

Magnesium Sulfate

The list of components told me that the mixture contains sodium, iron, manganese, zinc, copper, calcium, magnesium, and their counter ions such as chloride, sulfate, acetate, and phosphate, but it tells me nothing of the concentrations.  I wrote back to the supplier, including my comments on the importance of the relative amounts of these minerals (salts) in the “Beck salts” that they supply, and I included a reprint of the paper by Retnakaran and Beck 1967, but I never got an answer to the question about the concentrations of each component in the list that I copied above.  Evidently, the supplier considers the question of proportions of the mixture of insufficient importance to provide the answer to my question.  In my inquiry, I conceded that if the mixture was proprietary, then it should not be  referenced as a “Beck salts” mixture and that if the mixture was actually made by some other supply source, that supplier should be willing to fully describe their product.  I will write more in a future blog article about the nature of salts and their counter-ions and other characteristics, but clearly for the present article let me simply emphasize the importance of diet and rearing professionals knowing and understanding the complete nature of the mixtures that they use in diets.

What I have discussed here is a very specific example of how people who rear insects and often people who supply the rearing personnel with diets, diet components, or other rearing materials do not sufficiently take seriously the importance of what may seem to be minor matters.  I have heard many well-meaning rearing professionals express shock and dismay that suppliers may make changes in the rearing components they depend upon for quality.  Another assumption commonly held by rearing personnel is that there is an exact set of characteristics of diet or other rearing system components, and it is assumed that when we buy a brand of agar, salt mixture, wheat germ, or other material there is a sameness from one batch to another.  This assumption of sameness or “standardness” does not always hold up, and in my nearly 4 decades of rearing experience, I have seen dozens and dozens of instances when an otherwise stable rearing system crashed or manifested problems in the quality and quantity of their insects.

If my posts and other efforts to help us improve rearing raise the consciousness of rearing personnel about the importance of careful adherence to process control standards, I will have done something of value to rearing professionals and their stakeholders.

Happy Rearing!

Introducing werearinsects.com

Hello people in the insect rearing community. This is Allen Carson Cohen (aka, Allen C Cohen or Allen C. Cohen) announcing the new website and blog about insect rearing. Please come to this site to find out more about what we are doing to enhance insect rearing as a science and technology. We do education and research in the field of insect rearing.

I plan to offer a daily blog with comments and my thoughts about insect rearing, often with ideas from my current and past work with rearing systems and my interactions with rearing professionals.  I will also offer instructional materials and ideas for helping to make our rearing profession better able to serve the world.

Allen and silkworms

Allen Cohen with silkworms

K20538_cover

Allen’s 2nd Edition of Insect Diets: Science and Technology

Insect Rearing as Science

Rearing as science_Page_09

Comparison of Science and Art (from ESA Symposium Presented by Allen Cohen and Jackie Cohen)

Is Insect Rearing an Art or a Science?

One of the most important functions of this website and of the Insect Rearing Education and Research Program at NCSU is to help rearing specialists realize that good insect rearing practices are based on sound science practices.  We emphasize throughout our education and research efforts that understanding the biology and physical science behind all aspects of rearing is a must for reducing variability and unexpected or unpredictable outcomes.  We further stress that a science-based rearing technology helps us develop a statistically-sound process control over our rearing outcomes.  When we approach rearing as a science, we benefit from the tenets of science (rather than art) where we find mechanisms, cause-and-effect relationships, and sources of variability (error).  This approach makes rearing more reliable and more likely to give us repeatable and predictable results.  It also serves to help rearing specialists communicate their discoveries to other scientists who can repeat the work and build upon it.

The diagram summarizes briefly “science vs. art” with science being mechanistic, logically consistent, rational, repeatable, and offering predictive value.  These are some of the most important ideals that we hold for our rearing systems.  We also look for self-correction (continuous improvement and external input from peers) to make our rearing systems more successful.

As the posts and pages on the WeRearInsects.com website appear, we will further the ideas of “rearing as a science” with suggestions of using process control to make our rearing practices more “scientifically-based.”

Therefore, please keep track of the elements of science and technology that we try to convey in this site.

Happy Rearing!

Allen Carson Cohen

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