We learn best by doing rather than just seeing and hearing. The more we are involved in a learning process, the more we will gain from their educational experience. This axiom is clear to me after decades of teaching, and I keep trying to upgrade my teaching to rise to ever-increasing student/learner involvement.
In Fall 2024, I taught a class in insect rearing for first year life science students here at North Carolina State University.* Here is a sample of one of the slides in a presentation I did on metabolism of waxworms (Galleria mellonella) and how they use lipids and carbohydrates to generate elevated body temperatures.
From this image, FIRST YEAR students were able to write paragraphs explaining their understanding of how metabolism, size (accomplished here by larval aggregations), and insulation (accomplished by the waxworms with silk) could permit what we normally consider “cold-blooded” creatures (insects) to become warm-blooded. What I learned from the interactive paragraphs between the students and myself was that we could conduct a productive discussion that guided the “entry level” students to understand how the concepts behind metabolism, behavioural actions, structural adaptations such as fur, feathers, and silk could lead to waxworms’ cultural characteristics (their success in speeding their development, avoidance of predators and parasites, and many other advantages of making themselves warm.
The main point of this discussion is that the kinds of success we had with extensive student/teacher interactions was a much more efficient and enjoyable learning experience. Having learned this lesson from my freshman students, I vowed to apply it to all my teaching–including my online classes. Please look for future discussions of my interactive teaching ideas in post to come shortly.
We used this image complex in the First Year Life Sciences Class in Insect Rearing (called The Nature of Unnatural Insects: The Science of Insect Rearing Systems). We discussed how the tiny shrew and the world’s smallest hummingbird (each weighing about 2 grams) shared similarities with the waxworms whose thermal signature (lower right, yellow mass) were all able to attain and hold temperatures at least 10 degrees C above ambient. We discussed in our interactive email exchanges how metabolism, structural features such as fur, feathers, or silk could act as insulation, and biomass could be effectively increased by the aggregation of the larvae forming 2 gram masses.
The registration cost for this course is $450, and class size is limited to 20 people. If you have any questions about the course contents, please contact Professor Cohen at this email address: [email protected]
Professor Allen Carson Cohen will be teaching the Fundamentals of Insect Rearing in March and April 2025. This popular course will start on March 4, 2025 and continue to April 10, 2025. The format of the course is 12=two hour lectures, discussions, and questions/answers. The time of this real-time, interactive course is 10:00 am to 12 noon (Eastern Time) every Tuesday and Thursday.
The course is rich with videos of insect rearing dynamics, lots of visual materials and instruction in all aspects of rearing aimed at entry-level through intermediate level participants.
Unit/Lesson Name
Time Allotted
Content Description and/or Purpose
Unit 1: March 4, 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 1: To develop a unified understanding of the purposes of insect rearing systems, experimental design for rearing systems, who rears insects and why?
Unit 2: March 6, 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 2: Diets: Overview of Insect Nutrition and MetabolismBasics of insect nutrition and dietetics, essentiality concept
Unit 3: March 11, 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 3: Feeding Biology and Matching Diets with Feeding Biology; mouthparts, gut structure, excretion related to foods eaten by our insects.
Topic 5: Diet Development and Optimization: how do we develop diets? How do we optimize diets? More applications of design of experiments
Unit 6: March 20, 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 6: Diets: Diet Components—Chemical and Physical InteractionsAlso: Insectaries and Insect Rearing Equipment
Unit 7: March 25, 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 7: Insectaries and Insect Rearing EquipmentAlso: Domestication & Colonization
Unit 8: March 27 2025
2.0 hours (10:00 am to 12 noon, EST)
Topic 8: Consequences and managing colonized insects. What happens to our insects that we are domesticating by our rearing practices?
Unit 9: April 1, 2025
2.0 hours (10:00 am to 12 noon, EST)
Microbial Relations in Rearing Systems. What are the pathogens, symbionts, and other microbes associated with rearing?
Unit 10: April 3, 2025
2.0 hours (10:00 am to 12 noon, EST)
Reducing Error and Stress in Rearing Systems 1. How and why to use routine data collection and analysis to identify problems in our rearing systems.
Unit 11: April 8, 2025
2.0 hours (10:00 am to 12 noon, EST)
Reducing Error and Stress in Rearing Systems 2. How and what do we do to solve the rearing problems, inconsistencies, and other issues in our rearing systems?
Unit 12: April 10, 2025
2.0 hours (10:00 am to 12 noon, EST)
Quality Control of Reared Insects and Process Control. How do we develop SOPs and other aspects of quality control?
This is the course content for the Spring 2025 Fundamentals of Insect Rearing
The registration cost for this course is $450, and class size is limited to 20 people. If you have any questions about the course contents, please contact Professor Cohen at this email address: [email protected]
The dates of the class are Tuesdays and Thursdays at 11:00 am to 1:00 pm Eastern Time from May 7 through June 13.
Professor Allen Carson Cohen will be teaching the Fundamentals of Insect Rearing in May and June of 2024. This popular course will start on May 7 and continue to June 13, 2024. The format of the course is 12=two hour lectures, discussions, and questions/answers. The time of this real-time, interactive course is 11:00 am to 1:00 pm (Eastern Time) every Tuesday and Thursday.
The course is rich with videos of insect rearing dynamics, lots of visual materials and instruction in all aspects of rearing aimed at entry-level through intermediate level participants.
Unit/Lesson Name
Time Allotted
Content Description and/or Purpose
Unit 1: May 7, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 1: To develop a unified understanding of the purposes of insect rearing systems, experimental design for rearing systems, who rears insects and why?
Unit 2: May 9, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 2: Diets: Overview of Insect Nutrition and MetabolismBasics of insect nutrition and dietetics, essentiality concept
Unit 3: May 14, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 3: Feeding Biology and Matching Diets with Feeding Biology; mouthparts, gut structure, excretion related to foods eaten by our insects.
Topic 5: Diet Development and Optimization: how do we develop diets? How do we optimize diets? More applications of design of experiments
Unit 6: May 23, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 6: Diets: Diet Components—Chemical and Physical InteractionsAlso: Insectaries and Insect Rearing Equipment
Unit 7: May 28, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 7: Insectaries and Insect Rearing EquipmentAlso: Domestication & Colonization
Unit 8: May 30, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Topic 8: Consequences and managing colonized insects. What happens to our insects that we are domesticating by our rearing practices?
Unit 9: June 4, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Microbial Relations in Rearing Systems. What are the pathogens, symbionts, and other microbes associated with rearing?
Unit 10: June 6, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Reducing Error and Stress in Rearing Systems 1. How and why to use routine data collection and analysis to identify problems in our rearing systems.
Unit 11: June 11, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Reducing Error and Stress in Rearing Systems 2. How and what do we do to solve the rearing problems, inconsistencies, and other issues in our rearing systems?
Unit 12: June 13, 2024
2.0 hours (11:00 am to 1:00 pm EST)
Quality Control of Reared Insects and Process Control. How do we develop SOPs and other aspects of quality control?
This is the course content for the Spring 2024 Fundamentals of Insect Rearing
Coming in April of 2023, New Course in Insect Rearing Fundamentals!
The course is an online, live class taught by Professor Allen Carson Cohen. It is designed for people who are new to insect rearing (“entry-level” people) and for mid-level people who have some experience with insect rearing but want to know more of the comprehensive picture of how and why rearing system components fit together.
The course gives basics of feeding biology of various kinds of insects with mouthparts and digestive systems that are based on biting/chewing (such as beetles and Lepidoptera), piercing and sucking (such as Hemiptera/Homoptera), and lapping (such as many flies). The dynamics of the feeding systems are presented in coordination with the basics of insect nutrition and metabolism.
Other aspects of rearing systems are presented such as the nature and interplay of the rearing environment and how these factors lead to success or failure in rearing systems. For example, how do the details of gas exchange (O2 uptake and CO2 release) apply to cage/container design and population density? How does temperature impact feeding rate, metabolism, and reproductive success in our reared insects?
How do microbes (pathogens, symbionts, contaminants) affect our insects in their rearing systems? How do other sources of stress such as free radicals cause damage, and how can we avert such damage? How does stress, in general, affect the quality of our rearing systems’ products?
How does insect genetics and epigenetic phenomena affect our insect colonies? What are the realistic approaches to limiting and identifying the kinds of problems that nutritional, environmental, microbial, and genetic/epigenetic issues may cause?
The philosophy behind all of these topics and teachings is that the more insectary workers know about the interplay between our insects biology and the rearing system, the better each worker will do in developing and maintaining higher quality, stress-reduced insects as higher quality products of our rearing systems.
When? The new course in Insect Rearing System Fundamentals will be taught every Tuesday and Thursday at 11:00 am to 1:00 pm (Eastern Time) from April 4 through May 11, 2023.
Where? The new course will be taught through the Office of Professional Development at North Carolina State University and will be available through Zoom and Moodle (for presentation of class notes and other resources).
How Much? The new course will require a $450 USD fee for 24 hours of instruction.
Measuring gas exchange in container of painted lady butterfly larvae. The instrument shown here reveals the efficiency of O2 uptake and CO2 loss from the lidding of a typical rearing container. Note that the O2 level is about 19.6% (about 1.2% lower than “clean” air) and the CO2% is about 0.7 (which is about 7,000 ppm, 6,500 ppm above “clean air”). This raises the question about whether or not the gas exchange in this container is adequate for the larvae to grow and develop normally.
In a recent post (November 30, 2016), I discussed some of the foundations of Drosophila rearing, and I pointed out that much of the rearing that was done over the past century depended on the early works with Drosophila. In fact, the modern concepts of insect rearing must have originated in the 1910 paper by Delcourt and Guyenot: “The Possibility of Studying Certain Diptera in a Defined Environment.” This title, to me, represents and suggests the concept of CONTROLLED REARING.
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.
This is a “mini-review” of a new paper that was published on “Genetic and microbiome changes during laboratory adaptation in the key pest Drosophila suzukii. The authors of this paper (K. Nikolouli, H. Colinet, C. Stauffer, and K. Bourtzis) have made this important contribution in the journal Entomologia Generalis, Volume 42 (2022), Issue 5: pp 723-732, and they track wild D. suzukii from the field through multiple generations of laboratory culture. Nikolouli et al. point out that the assumption that field-derived insects make profound changes in their various adaptations, including genetic diversity and symbiotic community changes as they adapt to the artificial conditions of rearing. The authors summarize their work reported in this paper with the following statements “These results can serve as a reference for the design of an area-wide integrated pest management approach with a Sterile Insect Technique (SIT) component. Rearing productivity, biological quality, and mating competitiveness of a SIT mass-reared strain should be assessed in connection with genetic and symbiotic changes occurring during laboratory adaptation.“
The authors statements about the SIT context of these findings actually goes far beyond sterile insect technique, and the findings about changes in genetic characters of the target insects AND the microbiomes have profound implications for rearing for all other purposes, including biological control, insects as food and feed, and research.
A central tenet of the rearing program at NCSU is that insect rearing systems are artificial ecological niches of the insects we rear. This means that every aspect of the insect’s needs must be met by our rearing system. This responsibility of rearing personnel applies whether we know each requirement or not. For example, each insect (and each insect population in our colonies) requires a certain range of oxygen to meet their metabolic needs. We may not know how much oxygen this requires (the range of oxygen concentrations), but when we provide holes in the lid of the rearing container or a screen that permits gas exchange, we hope that the openings are adequate to meet the oxygen demands.
Therefore, we can think of the oxygen requirements as part of our insects’ ecological niche, and if our insects perform adequately under the conditions of our rearing containers, we assume that everything is OK “oxygen-wise.” We make the same kinds of assumptions about carbon dioxide concentrations and air flow and the same about water vapour. Sometimes we get ourselves in trouble when we try to restrict water loss from he diet or the insects by making the openings so limited that we wind up starving our insects of adequate oxygen (a phenomenon known as hypoxia or even anoxia); and/or we make create a situation of excess carbon dioxide, which can threaten our insects’ well-being.
In all the rearing courses that I teach, I try to convey to students that the rearing system with all its components that meet the insect’s ecological niche parameters is a complex set of interactions between various (ALL) components, and a helpful way of viewing all this is with a 3-D model or diagram such as what is seen here:
Model of the complex components in an insect’s ecological and REARING niche.
In this diagram that simulates or suggests three-dimensional space, I have tried to show about 20 of the many, many parameters in a niche. The diagram is intended to illustrate that there are interconnections and interactions that involve all the biotic (biological) and abiotic (physical/chemical) factors that play roles in our insects’ well-being. This model of N-dimensional hyperspace is derived from the work of the famous ecologist G. Evelyn Hutchison. I have used this model in my recent book, Design, Operation, and Control of Insect Rearing Systems 2021, CRC Press, Boca Raton, FL).
For this discussion, let us take-up a simplification of this diagram with 3 factors, heat, CO2, and O2. Here is the simplified diagram:
Three factors (heat, carbon dioxide, and oxygen) that are important in a waxworm rearing system.
In this 3-D, three-factor diagram, I am trying to show that the waxworm from my colony (of Galleria mellonella) is greatly influenced by the heat (temperature) conditions in their rearing container; but also, the concentration of CO2 and O2 are interacting factors that influence the metabolism and aggregation behavior of the waxworms, as well as food consumption, digestion rates, development rates, etc.
These interactions are illustrated in the images taken from my waxworm colony where I used a thermal imaging camera to capture the heat (thermal) gradient produced by the waxworms in this container.
Left: visual light image of waxworms and their architecture: right: infra-red image of the same colony space, showing the thermal gradients associated with aggregations of waxworms and the silken structures that the waxworms generate. This is the subject of a paper that I will soon be publishing in the journal INSECTS.
In the study of the colony described here, I have also included (besides the thermal profile) the CO2 and O2 gradient that results from the waxworms’ behavior and metabolism. The example, taken from waxworm cultivation in my research program, is typical of the kinds of multi-dimensional dynamics that apply to ALL insect rearing systems. My whole point in this and related discussions is to get students of insect rearing to recognise the complexities of their rearing systems components. It is further intended to awaken students’ appreciation for knowing the nature of (the science of) these many factors and their interactions.
This approach is not simple or easy; but it is very powerful in establishing and maintaining healthy, productive colonies!
Based on feedback from our students from rearing courses over the past 2 years, we are modifying our approach to the online courses. We are now offering a new rearing fundamentals course for entry level rearing background and mid-level background. The course will cover all major aspects of insect rearing systems with emphasis on basics of how components of rearing system function and how they interact.
Announcing the new Insect Rearing Fundamentals course starting April 4-May 11, 2023.This is a Drosophila feeding video made by Professor Cohen for his project on Mass-Rearing System Optimization for spotted wing Drosophila (D. suzukii).
An important part of the course on Insect Rearing Fundamentals is to give students/participants a better understanding of how various insects feed and how this knowledge helps lead to better rearing techniques. In this example, typical fly feeding dynamics are shown with the larva (in the center) using its hook-type mouthparts to help ingest food after it has been treated by the larva with its digestive enzymes (extra-oral digestion). The adults, especially the one in the upper left, are using their lapping/sponging mouthparts to help them ingest the yeast-based diet and diet matrix of agar and plant materials. This type of feeding applies to many families and species of flies, including the tephritid fruit flies (such as Mexflies and Medflies), which are extensively treated in this course.
This is a sample of the kind of conceptual and detailed explanations that Professor Carson Cohen provides in his lectures. Here are the topics that will be covered in the 12 units (lecture/discussions) in this course:
April 4: Lecture 1: The rearing system concept
April 6: Lecture 2: Diets: Overview of insect nutrition and metabolism
April 11: Lecture 3: Diet components–chemical and physical interactions
April 13: Lecture 4: Diets: Diet-making and diet presentation
April 18: Lecture 5: Diets: Optimization of diet composition
April 20: Lecture 6: Diets: Matching diets with feeding biology
April 25: Lecture 7: Domestication/colonisation (insect genetics and epigenetics)
April 27: Lecture 8: Microbial relations in insect rearing systems
May 2: Lecture 9: More microbial relations (kinds of microbes and kinds of interactions such as mutualism and pathology)
May 4: Lecture 10: Reducing error and stress in rearing systems part 1
May 9: Lecture 11: Reducing error and stress in rearing systems part 2
May 11: Lecture 12: Process control and quality control of reared insects
Each unit will include a 90 minute lecture with a 30 minute discussion section. This structure will allow for generous time for questions and answers that pertain to students/participants’ specific learning needs.
Students/participants will be given access to the NCSU Moodle system which gives access to class notes for each lecture and readings that are supplements to the lectures. The course is not graded, but quizzes will help provide feedback for students/participants to know where they may need explanation from the instructor.
