The Origins of Modern Insect Rearing: Drosophila

HEREDITY OF BODY COLOR IN DROSOPHILA T. H. MORGAN, 1912 Journal of Experimental Zoology PLATE 1 EXPLANATION OF FIGURES 1 2 A black female. 3 A brown female. 4 A yellow female. Normal or gray female (the outer marginal vein is slightly exaggerated in the figure). The contrast between the black, yellow, and brown flies is well brought out in the figures

HEREDITY OF BODY COLOR IN DROSOPHILA
T. H. MORGAN, 1912 Journal of Experimental Zoology
PLATE 1
EXPLANATION OF FIGURES
1. A normal female
2 A black female.
3 A brown female.
4 A yellow female.
Normal or gray female (the outer marginal vein is slightly exaggerated in
the figure).
The contrast between the black, yellow, and brown flies
is well brought out in the figures

These beautiful and historic drawings are from an early paper by the famous geneticist Thomas Hunt Morgan.  The many papers that he published helped establish modern-day genetics (not just insect genetics but ALL genetics).  These works and the other 150,000 papers on the various aspects of Drosophila genetics would not have been possible if it were not for the pioneering work of Delcourt, Baumberger, Guyenot, and other rearing pioneers.

Baumberger, J. P.  1917a. The food of Drosophila melanogaster Meigen.  Proceedings of the National Academy of Sciences of the United States of America: 3: 122-126.

Baumberger, J.P.  1917b. Solid media for rearing Drosophila.  American Naturalist.  51: 447-448.

Delcourt, A. and E. Guyenot. 1910. The possibility of studying certain Diptera in a defined environment. Comptes rendus hebdomadaires des séances de l’Académie des sciences (0001-4036), 151, p. 255-257.

Guyenot, E.  1913a. A biological study of a Drosophila ampelophila Low fly I – The possibility of an aseptic life for an individual and the line.  Comptes rendus des séances de la Société de biologie et de ses filiales (0037-9026), 74, p. 97-99.

Infrastructure: The Evolution of Rearing Systems: Pink Bollworms

In the previous post (Nov. 26), I brought up the subject of insect rearing infrastructure, and I showed a sterling example of a rearing system that has served the world well: the Pink Bollworm Rearing System: run by the USDA, APHIS in Phoenix, AZ (USA).  I showed a picture of the “pinkie” diet that was being mass-produced in a huge, industrial scale twin screw extruder.  Although the process is now practiced routinely by the highly skilled professionals at the Pinkie facility, the ideas and techniques behind this smooth operation did not “like Athena spring full-blown from the head of Zeus.”  There was an evolution of the process that serves today to produce up to 25,000,000 pinkie adults per day for sterile release.

dsc_0608-diet-extruded-onto-chilling-beltSo here is the pink bollworm system running at very high efficiency.  But how did it get that way?  What incremental steps went into the rearing system: the diet, the environmental conditions, the containers, the sanitation procedures, the genetic management of a highly domesticated insect, etc.?

pinkie-diet-tableLet’s take the diet as an example of the evolution of a mass-rearing system.  The above table is from a paper by Edwards et al.  (1996) cited below.  The Edwards paper describes how the twin screw extruder became incorporated into the mass-rearing system (another huge and important series of steps), but the formulation of the diet itself came from a complex of incremental processes, all of which had to be vetted.  Looking at the components, we see for example toasted soy flour, wheat germ, and agar.  Each of these components has a special role in the diet, nutrition, feeding stimulation, antimicrobial function, texture, stabilization, etc.  But where did the idea of soy flour come from?  It turns out that tracking soy flour (and other soy products) in insect diets requires some complex detective work (which I will discuss in another post).  However, it appears that soy products were first used by Japanese researchers who were trying to develop artificial diets for silkworms to reduce dependence on fresh mulberry leaves (please see my other posts on silkworms).  The soy/ silkworm papers began to appear in the early 1960s, and later in the ’60s other papers appeared where soy components were reported by Western researchers on insect diets.  I will treat the background in soy in insect diets in another post dedicated to this special topic.

Wheat germ is another component that is prominent in the pinkie diet and in diets for hundreds of other insect species. I have treated the history of wheat germ in my text, especially in the 2nd edition, and I will discuss it on a special topics page in a later blog, but for now let me point out that wheat germ made an inauspicious debut in 1959 and then a much greater impact study reported in 1960 (please see Vanderzant et al. 1959 and Adkisson 1960) .  Once the vast potential of wheat germ became recognized it has been of central importance in thousands of published studies where the insects could not have been available were it not for the excellence of what germ as a diet component.

The last item that I will mention here is agar.  It seems that agar has been around forever in insect diets, but it actually became a centerpiece of insect diets starting with a Drosophila paper by Baumberger (1917) and Baumberger and Glaser 1917.  Prior to 1917, media were being developed for Drosophila based on bananas and yeast, but the Baumberger laboratory borrowed from the then burgeoning programs in microbiology where agar was becoming a standard of many kinds of microbial media.  The advent of agar in insect diets revolutionized the potential for rearing hundreds of species of insects, yet the Baumberger and Baumberger and Glaser papers are cited only a total of 2 times since 1917!  This lack of citation and lack of recognition of some of the most influential achievements in insect rearing is a central topic of many of my writings and teachings.

Finally, the story of many of the other innovations and advancements is told remarkably well by Stewart (1984).  Again, I will treat the pinkie story in more detail in near future pages, but for now please understand my point about how much incremental progress must take place and should be recognized in the insect rearing systems upon which so much depends!

References Cited Here:

Adkisson, P. L., E. S. Vanderzant, D. L. Bull, and W. E. Allison.  1960b. A wheat germ medium for rearing the pink bollworm.  J. Econ. Entomol.  53: 759-762.

Baumberger, J.P.  1917. Solid media for rearing Drosophila.  American Naturalist.  51: 447-448.

Baumberger, J.P. and R. W. Glaser.  1917.  The Rearing of Drosophila Ampelophila Loew on Solid Media. Science.  45: pp. 21-22.

Edwards, R. H., E. Miller, R. Becker, A. P. Mossman, and D. W. Irving.  1996.  Twin screw extrusion processing of diet for mass rearing the pink bollworm.  Transactions of the American Society of Agricultural Engineering.  39 (5): 1789-1797.

Stewart, F. D.  1984.  Mass Rearing the Pink Bollworm, Pectinophora gossypiella.  In Advances and Challenges in Insect Rearing.  E.G. King and N.C. Leppla, Eds.  USDA, ARS.  Pp. 176-187. New Orleans, LA.

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.

 

Comments About Insect Rearing Infrastructure

dsc_0587-layer-cagesdscn0613-washed-egg-papers-drying-on-racks

I am currently writing a paper on infrastructure of insect rearing.  On this WeRearInsects.com site, I have already begun some of my discussion about rearing infrastructure and what our rearing profession needs to improve infrastructure.

One of the prominent examples of large scale and HIGHLY successful insect rearing is to be found in the various USDA, APHIS facilities, including the Pink Bollworm Rearing Facility in Phoenix, Arizona.

The photos in this post are from the Phoenix facility, currently directed by Eoin Davis, and previously directed by Ernie Miller and prior to that Dr. Fred Stewart.  The photos were provided by Dr. Hannah Nadel, a supervisory entomologist with USDA, APHIS.  These photos depict just a few features of the incredible mass-rearing system that is used by the staff of the USDA facility to produce millions of pink bollworms to be used for sterile insect technique (SIT) and other functions to help control these most devastating cotton pests.  The top left photo shows the adult rearing containers with PVC tubes collecting the scales, and the tops of the cages lined with paper for egg collection.  The top right photo shows the eggs being dried out after being treated with anti-microbial treatments, and the bottom photo shows the diet production where freshly made diet (diet with a red/pink dye to mark insects from the APHIS facility).  One of this laboratory innovations is the application of food science technology where the large twin-screw extruder is used to make large quantities of highest quality diet economically and safely.

dsc_0608-diet-extruded-onto-chilling-belt

This system is one of many USDA, APHIS facilities that deserves recognition and understanding by the rearing community, the entomological community, and the public at large, who are so well-served by these kinds of mass-rearing programs.  Thanks to these programs (including the sterile screwworm program, and several fruit fly control programs), billions of taxpayer dollars are saved, and our world is cleaner, and our agriculture is more efficient!

Reliability of Online Information: Questions of Trust and Critical Thinking

I have mentioned elsewhere on this site, that the purpose of the website, WeRearInsects.com, is to advance insect rearing through raising awareness of all rearing issues.  I have strived for the past 4 decades to contribute to science and entomology by doing research and teaching in insect rearing, and besides my writing books and book chapters, and papers, and besides my providing insect rearing workshops, and teaching classes online and in person, I have chosen to write a website to give myself the latitude to provide my ideas and the ideas of others all for the advancement of insect rearing and the people who practice this discipline.

However, I feel the need to express some thoughts and ideas regarding my site in the context of the site’s not being a peer-reviewed construct.

After the recent elections in the US, issues of truth, validity, and facts have come into the forefront more than ever before.  There have been many cases of fake news.  In fact, those of us who teach, have warned students for a long time that they need to be careful about “facts” from online inquiries.  I use the Internet many times per day to get a take on various subjects.  I have found that with subjects of which I have a base of knowledge, sometimes the information is excellent, and sometimes, it’s very inaccurate and can be misleading.  Therefore, my warning to students is that they use their greatest resource for getting an accurate (truthful?) picture is to use critical thinking and multiple source inquiries.  Part of the critical thinking that I urge is asking the question, “who is providing the information?” and “what does the information provider have to gain?”  Along with these critical thinking questions, if the student/scholar wants to add a layer of protection (a “truthfulness coating”), she or he can do some comparisons from various sources.  Often, however, the comparisons lead to the phenomenon where multiple sources say the exact same thing.  This parroting of information may well be a sign that the information should be further questioned, rather than being taken at face value.

So now, all this being said, what about the information that readers find on my website, which you are now visiting?  I have cautioned readers that this site presents my perspectives about insect rearing and related issues.  As much as I try to always be objective in my teaching, my scientific research, my reviewing other people’s works, and all other ways that I deal with insect rearing, I am still human and am bound to have slants or biases in the information and explanations that I present.  When I am writing papers or funding applications, I have reviewers who are scientific experts, and they can do some of the vetting.  Then, once the works are published, the scientific community can come along with criticism and commentary, especially if they have tested the information that I am providing.  This is why peer-reviewed works are given so much importance in the scientific community, especially where people are applying for funds, for jobs, or for promotions.

In the context of openness, I always encourage readers to offer opinions and to ask for clarification of my points.  However, to keep the site free of distractions, such as commercial messages or opinions that do not provide constructive substance to the ideas and information that I am putting forward, I screen the comments and questions, and I post all the ones that help what is in my opinion the advancement of insect rearing.

So please read my pages and posts critically, and give me feedback about what is helpful, what is incorrect, and what needs clarification.

Basic and Applied Science in Insect Rearing: Part I on Screwworms

Signed photo of E. F. Knipling who was honored by USDA, ARS in an article in Agricultural Research Magazine

Signed photo of E. F. Knipling who was honored by USDA, ARS in an article in Agricultural Research Magazine

One of the most heralded programs in entomology, possibly in science as a whole is the sterile insect technique (SIT) for suppressing or eradicating screwworms.  I present here a little background on the connection between insect rearing and application of SIT.  I start with a quotation from E. F. Knipling, who had long been a supporter of insect rearing as a science that supported other insect management programs such as SIT and biological control (unknown to more casual observers, Dr. Knipling was a GREAT supporter of biological control, including augmentation.  He wrote a book on the efficacy and possibilities of biological control by parasites, and he included predators and augmentation of both predators and parasitoids as an important potential for pest management on an area-wide basis.  He wrote:

“Mass rearing of insects is still a young science. With the help of insect geneticists, insect nutritionists, and insect behaviorists, insects might be reared under conditions that will make them equally, if not more, vigorous and more adaptable to the environment than the wild population. These improvements are likely to occur after further experiences and research.”  E. F. Knipling 1979

In the 2016 ESA National Meeting, Dr. Knipling’s work (for example, see the quotation from the ESA Newsletter announcement of Dr. James’ lecture*).  I have used in a paper that I wrote for American Entomologist the quotation from E. F. Knipling’s 1979 chapter to fortify my discussion of the pivotal role of insect rearing in entomological programs.  The quote reflects Dr. Knipling’s recognition of rearing as a science and that with the right kinds of input can lead to production of better quality insects that are more available for various programs.  It is also clear that Dr. Knipling had the vision that further “experiences and research” were needed to improve rearing science.

But for the current blog page, I wanted to fortify the point about basic science, in general.  I have cited a recent paper in Animal Behaviour (by Brennen, Clark, and Mock 2014) about the importance of basic science.  The authors clearly convey that basic science is of value far beyond the immediate scope or vision that most of us have initially. Brennen et al. cite the widely discussed treatment of Dr. Knipling’s work on screwworms, where Knipling was “awarded” a Golden Fleece Award for his having been funded for $250,000 to study on “The Sexual Behaviour of the Screwworm Fly,”  It has become a near-legendary example of near-sightedness by politicians like Senator Proxmire (D-Wisconsin from 1957-1989) that Knipling’s funding to study the mating behavior of screwworms, which was the foundation of SIT: that a female fly mates once, while males (including sterile males) mate multiple times.  Brennen et al. pointed out that the leverage from the 1955 Knipling study was amplified from $250,000 to $20,000,000,000 advantage in reduction of damages to US cattle.  Of course this economic and environmental advantage has continued to amplify itself due to the continuing positive effects of screwworm eradication throughout the US and Central America.  A further advantage of the sterile screwworm program is the demonstration (proof of principle) of SIT for tephritid fruit flies, pink bollworm, coddling moth, and several kinds of disease-transmitting biting flies.

*“Dr. Anthony A. James, a distinguished professor at the University of California, Irvine, delivered the Founders’ Memorial Award lecture at the 2016 International Congress of Entomology (ICE 2016). The subject of Dr. James’ lecture was Dr. Edward F. Knipling, winner of the World Food Prize (1992), the Japan Prize (1995), the FAO Medal for Agricultural Science (1991), the President’s National Medal of Science (1967), and many other awards.”

The Sexual Behaviour of the Screwworm Fly: One of the recipients of a Golden Fleece Award was E. F. Knipling for his research into the sex life of parasitic screwworm flies. Knipling developed the sterile male technique to eradicate this cattle pest, based on observations during the 1930s that male screwworm flies will mate with many females, while females will mate only once. He used this information to devise a male sterilization strategy using -rays. He released sterile males into the population and in a few generations completely eradicated this parasite. Knipling’s $250,000 grant from the Department of Agriculture led directly to a program estimated to have saved at least $20 billion for U.S. cattle producers. The sterile male technique is currently used as a standard eradication technique on many agricultural pests (Knipling, 2005; http://www.innovationtaskforce.org/docs/Screwworm.pdf).”

Brennen,

Knipling, E. F. 1979.  The basic principles of insect population suppression and management. USDA Agric. Handbook. 512.  659 pp.

*P. L. R. Brennan, R. W. Clark, and D. W. Mock.  2014.  Time to step up: defending basic science and animal behaviour.  Animal Behavior 94: 101-105.  (available at this site: http://www.bio.sdsu.edu/pub/clark/Site/Publications_files/animal_behaviour_commentary.pdf)

Insects as Human Food Part V: The Role of Mass-Rearing

So far, I have discussed several aspects of feasibility and practicality of using insects as a significant source of human food.  I have cited several documents that treat this topic, some with optimism, others with reserve, and I have expressed an overall reserve about the prospects.  I had expressed my opinion that the cultural objections would not be insurmountable, but instead, I suggested that the practicality of such a vision’s becoming a reality was in the production system.  I pointed out that gathering existing insects would not meet the growing need for human food as our population increases from more than 7 billion today (2016) to more than 9 billion by 2050.  I further discussed the gaps in our background that would allow us to farm insects in a production system that is derived from current insect farming such as cricket, mealworm, and silkworm production.

This leads to my major area of expertise: insect rearing (or MASS-REARING).  I have devoted the past 40 years of my life to better understand and contribute to rearing science and technology, so I feel that my views come from a background of serious study of this topic.  This includes my writing more than 100 papers on the topic of rearing, and my having read and reviewed more than 1000 papers on rearing (as an author, editor, and reviewer).

In this experience, I have studied the most successful and unsuccessful efforts to develop mass-rearing technology.  And with this background, I can say that there have been many pitfalls that had to be overcome for mass-rearing systems to become practical realities.  Probably the first true mass-rearing system was developed for screwworms (this somewhat neglects the rearing of silkworms on mulberry leaves, which I discuss elsewhere on this website), and it was not until the full-scale system could be developed over more than two decades of research that the sterile screwworm technique could be applied to a field-scale test.  With tephritid fruitflies, several systems are in operation, but these systems took decades to develop.  Other mass-rearing systems include the pink bollworm sterile release program, the boll weevil program (an area-wide system in the southern US), and several biological control systems.  In every case, it took at least a decade or more of cost and labor-intensive research to get the systems to a point that could be called true “mass-rearing.”  And as I treat in my book on Insect Diets: Science and Technology (2nd Edition), the actual biomass produced in any of these systems falls far short of what could make a significant impact on impending world hunger crises.

In all the cases of successful development of true mass-rearing systems, the most important deciding factor (as to whether or not the system would succeed in achieving mass-rearing) was automation.  Along with the automation advancements, there had to be developments of diets/feeding systems, diet presentation systems, containerization, environmental optimization, management of microbial factors (contaminants and symbionts = bad microbes and good ones), management of potential for genetic deterioration, and waste management (thousands of pounds of scales produced as potentially hazardous waste from pink bollworm production and tons of carcasses, spent food, deteriorated containers, etc.).

These are all parts of mass-rearing systems that required often exquisitely elaborate and deeply thought out research on how to deal with these issues.  Just the most basic example faced in mass-rearing facilities is how to deal with toxins like formaldehyde or sodium hypochlorite (bleach) in surface-sterilizing eggs.  Just this simple sanitation question requires detailed and well designed experiments or tests that guide rearing system managers as to how to deal with these and myriads of other problems in establishing and running complex rearing systems.

It is these issues to which this website is devoted.  And I will discuss some of these issues further in the next few blog pages.  Please stay tuned.

Insect Rearing vs. Insect Farming: Part I

http://www.csrtimys.res.in/structure/seri-engineering-division Central Sericultural Research & Training Institute (CSRTI), Mysore [An ISO 9001 : 2008 Organisation] CENTRAL SILK BOARD - MINISTRY OF TEXTILES - GOVT. OF INDIA

http://www.csrtimys.res.in/structure/seri-engineering-division
Central Sericultural Research & Training Institute (CSRTI), Mysore
[An ISO 9001 : 2008 Organisation]
CENTRAL SILK BOARD – MINISTRY OF TEXTILES – GOVT. OF INDIA

I

 

 

 

 

 

silkworms-in-viet-nam

Raising silkworms Hoi An Quang Nam, Vietnam www.gettyimages.ae

I have been trying to make useful distinctions between insect farming and insect rearing.  The differences that I suggest are that while farming is lower input and less controlled than rearing, rearing can usefully be distinguished with the incorporation of artificial diet.  While silkworms have been farmed for nearly 5000 years on their natural host (mulberry leaves), and honeybees have been managed but allow to feed on natural (or wild) foods, rearing with artificial diets began in the 19-teens when Drosophila species were given modified banana with yeast and agar added.  This set the stage for artificial diet-based rearing, which has been developing over the past 100 years.  I realize that if you grow a pepper plant in your lab or green house, and use that plant to support a colony of aphids, you are in a sense rearing the aphids.  But you are limited in your control over the plant’s nutritional value to the aphids.

So the distinction that I am making is based largely on INPUT and CONTROL.  With pre-farming  activities hunting, fishing, and gathering, the foods and other items like clothing, tools, etc. were not processed at all or not very much.  The early humans probably started off killing small animals by hand, grabbing fish out of the water, and picking plant materials.  As they started to use tools for hunting, fishing, and harvesting, they started to have a little more control, but when they domesticated plants and animals, they had higher levels of control, more predictable outcomes, and they were becoming agriculturalists (farmers).  I see insect farming as having input and control over the intended products.  The next steps add the control of the insects’ environment, its food, which insects breed with one-another, etc.  This tendency towards control gives much more reliable outcomes, and my insistence upon making rearing into a more and more scientific process is in line with the concept of predictable outcomes.

In the film clip on this page, I show the silkworms that I have been rearing on artificial diet.  But also, I include an image of the efforts that silk producing countries are making at reducing the labor and expanding the scope of silkworm farming such as the mulberry field in India where automation and machinery are being adopted to increase the yield of mulberry per hectare of land.  The same engineering organization is adding as much automation as possible to silkworm production, compared with the production of silkworms in the facility in Vietnam (which is still a very impressive process, though it may date back to hundreds or thousands of years of silkworm farms).

More on these points in future pages.

Who’s Who in Rearing: Part I

Please note: these pages on who’s who in rearing are thematically related to the pages that I have been posting on eating insects.  I have taken a slight turn here to work into this website some background on the variety of people and programs where insect rearing is central.

Using mulberry bushes, rather than trees reduces costs of farming silkworms

Using mulberry bushes, rather than trees reduces costs of farming silkworms

 

 

 

 

http://www.tammachat.com/

 

 

 

Laotian woman sorting silkworms: throughout rural Asia, tens of thousands of families make their living rearing silkworms and harvesting raw silk

Laotian woman sorting silkworms: throughout rural Asia, tens of thousands of families make their living rearing silkworms and harvesting raw silk

 

  • Woman removes silk worms from mulberry leaves
  • Credit: Margie Politzer
  • Creative #: 165661631
  • Ban Xang Khong, Luang Prabang, Laos.
  • www.gettyimages.ae

 

 

 

 

Who Is Rearing Insects?

This section of my blog pages is intended to provide an overview of people and institutions that are conducting significant rearing operations.  It cannot cover every high performance rearing operation for several reasons: 1) I cannot know all the people and organizations that do rearing, 2) there are so many rearing operations in existence that there would be no room to cover them all, and 3) many of the operations are doing rearing that is proprietary (such as private companies).  Based on my knowledge of the rearing community, I have estimated that there are at least 10,000 (possibly 20,000) people around the world who make their living or spend most of their time rearing insects.  These people do their rearing as part of research in educational institutions, for production by private companies, as part of government programs, and in a surprisingly diverse number of domains.

After spending a quarter of a century as an insect rearing specialist in the USDA, Agricultural Research Service, I thought that I had a grasp of the scope of insect rearing.  But as a rearing consultant in a private company and later as coordinator of an insect rearing program at North Carolina State University, I have been surprised at the number and kinds of rearing efforts around the world.  Here is a brief list of types of rearing operations:

  1. International Organizations such as the United Nations, FAO (Food and Agriculture Organization), WHO (World Health Organization).
  2. Large federal government laboratories: for example, 1) the USDA has rearing presence in the Animal and Plant Health Inspection Service or APHIS, the 2) Forest Service, 3) the Agricultural Research Service, the 4) Canadian Forest Service, 5) Ag Canada, EMBRAPA, The Brazilian Agricultural Research Corporation, 6) the Australian Centre for International Agricultural Research, 7) French National Institute for Agricultural Research (INRA), 8) Department of Agriculture and Rural Development (Great Britain), 9) IRTA in Catalonia, Spain, 10) CIGAR in Africa (Nigeria, etc.), 11) IAR (Iran Agricultural Research), 12) Agricultural Research Organization, Volcani Center (Israel), 13) ARC or Agricultural Research Center, Egypt (under the Ministry of Agriculture and Land Reclamation), 14) International Food Policy Research Institute (China and Eastern Asia), 15) National Agriculture and Food Research Organization (NARO in Japan), 16) Indian Council of Agricultural Research (ICAR), and many, many others. My references are biased towards North America, but every nation in the world has its own (sometimes multiple) organizations or works within a consortium of countries or umbrella organizations to rear insects for protection of food, for medical purposes, or for research.
  3. State (or province) programs: in the US, for example, every state has its own department of agriculture or plant industry, and many of these have significant rearing facilities including some major rearing facilities.
  4. University rearing laboratories (no matter how small the college or university there are almost always rearing efforts that provide insects used as research and educational tools).
  5. Private Industry: 1) the companies that use insect rearing for their internal research and 2) the companies that produce insects directly for sales where the insects are used for food for other organisms, as biological control agents, as educational resources, and even as live creatures for various kinds of celebrations.

This list of various entities where rearing is practiced, sometimes on a major scale that employs dozens to hundreds of people in a single facility hardly expresses the scope and diversity of insect rearing operations.  Just imagine, for example, how much effort goes into rearing Bombyx mori for silk production.  Just in the silk industry in India alone, for example tens of thousands of families make their living in rural India by farming mulberry and rearing silkworms. I have included an interesting paragraph from the Gangopadhyay (2008) paper where sericulture is described.

From:  Sericulture Industry in India – A Review from India Science and Technology

By D. Gangopadhyay 2008. http://www.nistads.res.in/indiasnt2008/t6rural/t6rur16.htm

“Sericulture is both an art and science of raising silkworms for silk production. Silk as a weavable fiber was first discovered by the Chinese empress Xi Ling Shi during 2,640 B.C. and its culture and weaving was a guarded secret for more than 2,500 years by the Chinese. Silk was a profitable trade commodity in China. Traders from ancient Persia (now, Iran) used to bring richly coloured and fine textured silks from Chinese merchants through hazardous routes interspersed with dangerous mountainous terrains, difficult passes, dry deserts and thick forests. Though, commodities like amber, glass, spices and tea were also traded along with silk which indeed rapidly became one of the principal elements of the Chinese economy and hence, the trade route got the name ‘SILK ROUTE’. Even today, silk reigns supreme as an object of desire and fabric of high fashion. Being a rural based industry, the production and weaving of silk are largely carried out by relatively poor sections of the society and this aspect of sericulture has made it popular and sustainable in countries like China and India.”

It’s tempting to spend considerable time discussing the silkworm rearing industry because of its long-standing importance on the world stage for millennia, but the other aspects of insect rearing are more of the focus of this series on “who’s who in rearing?”  In future posts, I will discuss the overview of rearing and more details about the various rearing operations.

 

Why process control is valuable in rearing

Insect rearing is a process.  However large or small the rearing system is, the principles of process control can be made applicable.  As a result of controlling the rearing process, we have a more reliable, economic, and practical system.  The outcome of process control measures is almost certainly an improved product, which in this case is the insect population that we produce to meet our needs for research subjects, as the fundamental components of pest control systems, as food for other organisms, or whatever else our purpose is in rearing insects.

As processes, insect rearing systems are subject to the “rules” of process control.  These rules include the fact that data-driven processes can be subjected to analysis of where things may be going wrong and how potential problems can be prevented or minimized.  Therefore, statistical process control (SPC) can be a tremendous asset in helping us to organize our rearing systems.  As processes, insect rearing systems can best be improved and made predictable (and more quality-driven) by collection and analysis of data in our rearing process.

Fundamentals of Process Control: Inputs and Outputs

Fundamentals of Process Control: Inputs and Outputs

As an aid to explaining how we can visualize our rearing system in a model, I offer the above diagram that I adopted and modified from the Montgomery 1992 reference.

Eating Insects Part IV: Insect Farming: Alchemy vs. Science

In the past several blog pages that I posted, I discussed issues that are of broad interest rearing using insects as human food.  The following paragraph presents the major issues, and so far, I have discussed 1) through 3).  In this blog I will treat item 4).

Throughout this page, I am using the expression IHFE to name the Insects as Human Food Enthusiasts.

Some Basic Questions and Organizing Principles: 1) Will social or cultural constraints make it unrealistic to use insects as human food? 2) Does the food value and food safety of insects impose impossible constraints? 3) Will gathering insects from nature allow us to make a significant “dent” in the needs for human food? 4) Will systems of farming insects become feasible to make significant advances in the use of insects as human foods? 5) How far can insect mass-rearing go towards allowing us to produce enough quality insect biomass to have a significant impact on the growing needs for food?

Farming vs. rearing insects: I am making a distinction here between farming and rearing, where I consider farming a lower input process of insect production than rearing (which I consider more input intensive and more rigorously managed than insect farming).  This is my own distinction, which I think will be useful in the overview that I am trying to establish.  We already use what I would consider a hybrid between farming and rearing in production of silkworms fed mulberry leaves, crickets fed various mixtures of grains and supplementary materials such as vegetables and scraps from food processing systems.  Conventional production of meal worms is based on supplying grains and some vegetable materials such as potatoes and carrots as supplements to the grains and sources of moisture.  In each of these cases, millions of insects are handled in the production facilities.

In the case of silkworms, the major input is fresh mulberry leaves, and through the 5000 years of silkworm cultivation many improvements have been made in selection of optimal mulberry trees as well as leaf harvesting and presentation processes.  The considerable expense of maintaining orchards of prime mulberry and the labor in the silkworm farms though somewhat costly are rewarded by the very high price that quality silk brings to the producers.  The cultural implications of silk production is a remarkable story unto itself, but for our purposes, the silkworm model serves as an excellent example of getting a large scale biomass of insects from a fairly simple input.

For crickets, the use as food for other organisms drives the production system, and the question of cost/benefit is clearly understood when we realize that crickets are used by people who are willing to pay very high prices for crickets to feed their pets or for use in zoos and conservation programs.  I have indicated in my text (Cohen 2015) that cricket protein at current market prices is more expensive the protein available from the finest cuts of beef.  When we think about the cost of crickets from local pet stores being upwards of 10 cents per cricket, our incredulity is explained by realization that pet owners may pay 50 to 100 dollars for a pet lizard (some specially bred leopard geckos can be sold for upwards of $1000!)  So pet owners don’t flinch at paying 10 cents per cricket to keep their lizards (or tarantulas) happy.  However, if crickets are going to be used as human food at a scale that truly meets problems of human population growth and world hunger, then 10 cents per cricket would not be reasonable.  Taking for example, a 0.1 to 0.2 gram cricket and an estimated protein content of 10% of the cricket’s biomass, it would take 100 crickets to provide 1 g of protein, and given the FAO/WHO standard of 50 g of protein as a basic human adult requirement, it would take between 2,500 to 5,000 crickets to meet the daily requirements of a human adult male.  At 10 cents per cricket (admittedly a high price of retail crickets), it would take $250 to $500 per day to supply human protein needs from these crickets.  If the crickets’ cost were brought down to 1 cent per cricket, the cost of meeting the human protein needs would be 25-50 dollars a day (way more than we would expect people from emerging nations to be able to pay.  I realize that humans would not be expected to subsist on crickets alone.  The diets of insect-eating people would contain vegetables, other sources of meat, etc.  But the extreme example that I offer is based on the assumption that we are striving to make insects a significant contribution to the nutritional needs of our growing world population.  So how much insect protein would be considered a significant insect protein contribution?  If it were only 10% of the protein needs, then at the rate of 1 cent per cricket, it would require $2.50 to $5.00 per day to meet that need.

Clearly, all this means that the price of cricket production MUST come down to something more like 0.1 cent per cricket.  This means that other ways of cricket farming must be developed, and this is where the promises of the insects as human food enthusiasts (IHFE) need to do some deep thinking (and I think lots more research).  The standard argument that I have been hearing from the insects as human food advocates is that we can use really inexpensive foods for the crickets (or other insects to be produced for human food).  The IHFE folks argue that we can use waste streams such as food wastes and crop residues can be used to produce crickets.  This topic is covered elegantly in the paper in this paper: Lundy ME, Parrella MP (2015) Crickets Are Not a Free Lunch: Protein Capture from Scalable Organic Side-Streams via High-Density Populations of Acheta domesticus. PLoS ONE 10(4): e0118785. doi:10.1371/journal.pone.0118785 ).  These authors showed that there is nothing magical about crickets in terms of ability to convert low quality organic materials into nutrient-rich human food.

This is where I offer the concept of ALCHEMY vs. SCIENCE.  My wife, Jackie,  suggested this metaphor when I was explaining to her what I felt that IHFE people were expecting.  The practitioners of alchemy sought to convert the baser metals such as lead into gold.  The idea is intriguing that a wizard could use some kind of magic to make a cheap, common substance into a precious metal.  Of course we know today that this is not possible: our science teaches us why this kind of expectation is unrealistic, just as the laws of thermodynamics teach us that perpetual motion machines are fancy.  Yet, today, we still hope to get something for nothing or to get a lot of output from little input.

This is what I suggest that we are doing when we pursue conversion of low quality materials into nutritious insect biomass.

Besides the cricket systems, many IHFE supporters are enthusiastic about soldier flies, advocating that we can use poultry manure to rear high quality, high nutrition food (soldier flies) from the wastes that are abundant in poultry production systems.  I hope that I am clear about this: I am very supportive of recycling and systems of waste management that are efficient.  It would be useful to devise farming (or rearing) systems that allow us to use insects to help clean up wastes and at the same time can be used as foods for livestock.  The concept of using waste products as fertilizer is certainly in this line of thinking.  The use of Candida utilis (known as torula yeast) for conversion of wood pulp products that were wastes from the paper industry to a palatable and nutritious yeast product is well-documented as are other fermentation or bio-manufacturing procedures.  Use of algae to convert raw materials to nutritious food or biofuel has been accomplished with a fair degree of success.

So I am not saying that insects cannot be used in well-designed systems to improve waste remediation or other low input and sustainable strategies.  But my seeming iconoclasm is in response to the many claims that I keep reading and hearing about the magic bullet that insects will be to solve world hunger problems.

My major point about this is that there are sizeable gaps in our knowledge of insect husbandry that must be filled before we have any hope of making progress towards the scale of insect production that IHFE people are missing.  Filling that gap is the purpose of this website and the program that it represents.

 

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