Study finds tray position can shift black soldier fly output
Bottom line
A new study in Animals suggests that black soldier fly production in stacked tray systems may be less uniform than many operators assume. Researchers Alondra Guerrero-Hernández, Aurelio Guevara-Escobar, and Juan Fernando García-Trejo tested same-age third-instar Hermetia illucens larvae at a constant numerical density, while varying initial larval mass to change biological load, and found that both biological load and tray position shaped larval biomass yield and dry frass output across the stack. The paper focuses on a practical question for industrial insect production: whether where a tray sits, and how much larval biomass goes into it at the start, can create measurable production heterogeneity in otherwise standardized systems. (journalsworld.com)
Why it matters: For veterinary professionals tracking the insect-protein pipeline, the study adds another reminder that production conditions can influence not just output, but potentially the consistency of insect-derived ingredients and frass co-products. That matters as black soldier fly ingredients continue to move deeper into animal nutrition and circular agriculture, and as prior research has shown that tray-level conditions, feeding strategy, substrate, and system design can affect larval yield, frass generation, and downstream product characteristics. Frass volumes can also exceed larval output in many systems, making process control important on both the feed ingredient and waste-management sides. (mdpi.com)
What to watch: Expect follow-up work on whether tray-position effects can be reduced through ventilation, loading protocols, feeding schedules, or stack redesign, especially as producers push for more standardized insect meal and frass streams. (scijournals.onlinelibrary.wiley.com)
Key facts
- Study
- A new study in Animals examined black soldier fly production in stacked tray systems.
- Researchers
- Alondra Guerrero-Hernández, Aurelio Guevara-Escobar, and Juan Fernando García-Trejo.
- Species
- Hermetia illucens.
- Larval stage
- Same-age third-instar larvae.
- Design
- Numerical density was held constant, while initial larval mass was varied to change biological load.
- Main finding
- Biological load and tray position shaped larval biomass yield and dry frass output.
- Production system
- Stacked tray rearing system.
- Practical takeaway
- Two trays with the same number of larvae may still perform differently depending on starting larval mass and tray level.
A new Animals paper puts a finer point on a familiar industrial insect-farming problem: identical trays don’t always behave identically once they’re stacked. In “Biological Load and Tray Position Shape Larval Yield and Frass Production in a Stacked Hermetia illucens Rearing System,” researchers report that both initial biological load and tray position affected larval biomass and dry frass production in black soldier fly systems, even when larval numerical density was held constant. (journalsworld.com)
That matters because stacked tray systems are widely used to scale black soldier fly production, but they also introduce microenvironment differences from one level to the next. Earlier work has already shown that production outcomes can shift with feeding frequency, tray size, substrate choice, and overall system design. In one pilot-scale MDPI study, food waste bioconversion produced roughly 550 g of larvae and 530 g of frass dry matter per tray over 10 days, underscoring how closely larval yield and frass management are linked in commercial practice. Other reviews and production studies have noted that frass can be generated in volumes that rival or exceed dried larval output, which raises the stakes for process consistency. (mdpi.com)
According to the study summary, the researchers used same-age third-instar larvae and kept numerical density constant, while changing initial larval mass to impose different biological loads. They then evaluated how those loads interacted with tray position in a stacked rearing system to affect two core production metrics: larval biomass and dry frass production. Even without the full dataset in the source summary, the framing is operationally useful: it separates headcount from biomass, suggesting that two trays stocked with the same number of larvae may still perform differently if the starting larval mass differs, or if the trays occupy different levels in the stack. (journalsworld.com)
The broader industry context supports that interpretation. A recent JSFA Reports paper on bridging lab and industry in black soldier fly production highlighted HVAC and environmental control as critical to keeping rearing units operating at full capacity. Meanwhile, industry commentary has increasingly emphasized routine weighing, logging, and tray-by-tray monitoring rather than treating stacked systems as biologically uniform. One recent industry post described scales and production metrics as foundational tools, and explicitly asked producers to think about count per tray and whether they had deliberately adjusted it to find the right operating “recipe.” That’s not peer-reviewed evidence, but it does reflect where commercial attention is moving. (scijournals.onlinelibrary.wiley.com)
Why it matters: For veterinary professionals, this is upstream research with downstream relevance. Insect protein is being positioned as a sustainable ingredient for animal feed, and black soldier fly systems are also generating frass streams that may be marketed into agriculture. If tray position and biological load introduce meaningful heterogeneity, that could affect consistency in nutrient recovery, processing efficiency, and potentially the quality profile of insect-derived ingredients entering feed chains. It also reinforces a familiar lesson from livestock and feed manufacturing: biological systems rarely stay uniform just because the equipment looks standardized. (mdpi.com)
There’s also a co-product angle. Frass isn’t just a byproduct to be moved off the line; it’s increasingly treated as part of the business model. Reviews of black soldier fly frass note growing interest in its fertilizer value, but also substantial variability tied to substrate and rearing conditions. If stack position changes frass output, producers may need tighter process controls before they can make reliable claims about frass volumes or characteristics across batches. (mdpi.com)
What to watch: The next step is whether producers, equipment suppliers, or follow-on studies translate this into specific operating guidance, such as preferred tray-loading ranges, stack-height limits, airflow adjustments, or separate QC thresholds for top, middle, and bottom trays. As insect production matures, studies like this may help define what “standardized” really has to mean in commercial black soldier fly systems. (globalseafood.org)