One aspect of producing BSF is the typical approach taken for growing BSF is quite general (i.e., not detail oriented). Young larvae are put in a pan with a specified amount of food with the expectation that after a given amount of time, the larvae will peak in terms of growth and food digestion and then be harvested.
As you all know- what we expect and what actually occurs can be quite variable- Biology just does stuff like this (i.e., variation). So, I am often asked how do we develop a more precise approach to producing BSF, while maintaining a high level of precision and accuracy with the model produced?
My typical answer is- well, researchers/industry just have not developed such a system yet (that is publicly available).
However, studies, such as the one about to be listed might be the next step needed to develop a more precise method for mass production of BSF.
Gligorescu, A., S. Toft, H. Hauggaard-Nielsen, J. A. Axelsen, and S. A. Nielsen. 2019. Development, growth and metabolic rate of Hermetia illucens larvae. Journal of Applied Entomology 143: 875-881.
The overall conclusions that I reached after reading this article are the following:
1. Prediction of growth patterns of BSF larvae is relatively consistent (as expected) with slow growth initially followed by vertical growth (i.e., think- weight over time) and then a plateau. This overview is not new, but it does illustrate a point. There is a window of maximum growth producers want to identify with their colony. Predicting when that portion of the growth pattern is complete should represent a harvesting time point. By identifying this point in development, producers could reduce their "in pan" production time by 2 days or more. From a production standpoint, reducing development time that amount is quite significant as related to space occupied by pans and resulting production.
2. Heat generation (significant) occurs at a set point in the development cycle. Producers should be aware of this time point- too much heat and the waste will compost and the larvae will stop feeding. A remedy would be to identify that time point, mix the waste, and allow the heat to escape (be aware, such a process also blends the BSF waste with food not consumed which could be an issue).
3. Something not discussed, or I missed it, is along this growth pattern, the larvae will shift from protein accumulation to fat accumulation. If identified, producers could harvest larvae with different nutrient compositions (e.g., high protein/low fat and vice versa). Of course, many of you have already thought about this point I am sure. But, I like to put it out there for others to consider.
Jeffery K. Tomberlin, PhD, Enjoying fall weather in Texas
An area sorely overlooked in our field is the use of the digestate remaining after BSF are used to recycle organic waste as a fertilizer or plant substrate. The following paper explored this topic.
Setti, L., E. Francia, A. Pulvirenti, S. Gigliano, M. Zaccardelli, C. Pane, F. Caradonia, S. Bortolini, L. Maistrello, and D. Ronga. 2019. Use of black soldier fly (Hermetia illucens (L.), Diptera: Stratiomyidae) larvae processing residue in peat-based growing media. Waste Management 95: 278-288.
In the study, they raised BSF on the standard Gainesville House Fly Diet. So, the residue is a bit "laboratory"; however, I think they selected the appropriate starting point. Based on data generated from this study, future research can explore residues from other organic material digested.
The takeaway- yes, the waste/digestate can be used as a partial commercial peat replacement (20%) to grow baby leaf lettuce, basil, and tomato.
But- we really need to build on these results and explore different residues (i.e., different organic material digested by BSF) as substrates for growing plants.
Insects as Food & Feed in the News!
Robots Producing Insects (USA): Great video on cricket production. Also, nice discussion on the global perspective of insect farming.
Insects to Feed Pets (UK): A discussion on insects as food for pets- with some suggestions of items dogs shouldn't eat.
Cookies & Insects (EU): An overview of insects as food ingredients.
Bugtoberfest (Texas, USA): A great outreach event on entomology in general.
Jeffery K. Tomberlin, PhD, Loves the Bugtoberfest Concept!
Individuals with over 25 years research experience with the black soldier fly. We are passionate about the science behind the black soldier fly and its ability to convert waste to protein.
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