Mealworms vs BSF

Based on my humble understandings:

Mealworms do no consume a lot of water and their farming does not take up much space and can be converted to protein powder quite easily but from what I have seen all they can eat are grain byproducts (which here in Morocco we actually eat such as wheat bran and the like. Meaning they compete with humans and other animals[cattle, sheep, chickens] for the same least here). It also means they indirectly consume a large sum of water since these grain byproducts had a large share of the irrigation water. Additionally wheat bran in not cheap at all from an economic perspective. (here it is $0.18 to $0.2). NOTE: Mealworms optimum FCR is 2. Mealworm protein content is 20% (from grubco website). so almost 9-10 kg of wheat bran is needed for 1kg of pure protein powder. So just the feeding of the larvae would cost nearly $1.6-1.8. Here, that is much more expensive than fishmeal.

BSF consume organic waste that should have certain constituents which is a great sustainability opportunity. However, the logistics of retrieving organic waste should be well studied since you might be harming the environment in other ways. They use a lot of space and from what I have read no clear method of de-fattening them has been found.

So in order to make both these options sustainable options and commercially viable:

Do you believe there is a future of de-fattening BSF efficiently? Do you believe there is a way to retrieve organic waste efficiently? Do you think that there is a possibility that mealworms can eat organic waste rather than grain byproducts?

Hopefully I am wrong in some of my assumptions above and that there already have been breakthroughs in some of the issues raised here.

Cant wait to hear your opinions and take on this.



  • I'm no expert in any of this, but I wonder if dead beetles could be a reliable source of organic matter for BSFs. If you raised both you could throw a bit of permaculture mentality and at least allow one to feed the other.

  • edited September 29

    Hi Abdoullah, - Black soldier fly larvae "fat" (oil, lipid) in published research has been obtained by grinding them up & placing the mash into a porous bag, then submerging that filter bag for 48 hours in petroleum ether (solvent) at ambient temperatures. After 2 days take the full filter bag out of the solvent & submerge it into fresh solvent for another 48 hours soaking at ambient temperature.

    Combine the 2 batches of solvent with their extracted oil content & seperate out the solvent. This is can be done using a piece of laboratory equipment called a "rotary evaporator".

    This piece of equipment tumbles what you crudely extracted into the solvent in a continuous thin layer inside a glass flask allowing the solvent to evaporate off the enclosed surface. These apparatus heat (usually under vacuum which requires less temperature) the operational parts to vaporize solvents & are designed so vaporized solvent is then condensed into a different glass flask for collection.

    As for what solids remain inside the filter bag, that is where you'll find the protein (among other components). That mush will have adsorbed (stuck to it, not incorporated into it) some of the solvent. Most of the adsorbed solvent would evaporate if exposed to open air (or better yet low heated under vacuum with a purge valve to bleed off solvent vapor from inside the enclosed chamber).

    But depending on what wish to do with the solids it could be worthwhile to subject it to a sequence of "washing" & drying, remember water is also a solvent. Different solvents act differently on things & possibly (in theory) you may find it easier to work initialy with hexane (not very toxic incidentaly, but fumes are deceptively nasty); which is commonly used to extract seed oil.

  • edited September 29

    This link may be of interest. See:

    *Section "3.2" discusses how much fat is extracted using petroleum ether based on whether 1,000 black soldier fly larvae fed different manures processed after 10 days of manure diets (kept at 60-75 humidity & 27 Celsius) when reared on chicken manure (98.5 gr fat), or on pig manure (60.4 gr. fat), or cattle manure (38.2 gr fat). Before submitting larvae to solvent extractions they were washed off, killed (5 minutes at 105 Celsius), dried (48 hours at 60 Celsius), frozen & then ground up for solvent bath described in preceding comment.

    ** Table 1 charts out the relative weight of these larvae fed different manure & although not specifying protein content does give an indication of how big (biomass) they got on different manures; as well as which manure produces more fat content in the larvae.

    If you want to know about rearing black soldier fly then this Thesis (2017) may be helpful since the student was influenced by the South African company AgriProtein Technologies. Free full pdf is available at bottom left where university repository abstract found for D. Britts' work "Improving feeding efficiencies of black soldier fly larvae, Hermetia illucens (L., 1758) (Diptera : Stratiomyidae : Hermetiinae) through manipulation of feeding conditions for industrial mass rearing";

    To help readers get into the subject check out Thesis section 1.8.4. There you can find references to feeding black soldier fly larvae on kitchen waste & vegetable waste that may be useful.

    The text is long so here are some points that stand out. On pg. 86 the conclusion is reached that optimal feed utilization is related to depth of feed (diet) supplied the larvae. For commercial scale operations that optimal depth is under 10 cm & if want to maximize the larval size (& minimize development time) the optimal feed depth is only 5 cm (graph illustrations of this issue begins on pg. 98).

    On pg. 115 the conclusion is that the best rate of adding feed for the larval population is 125 mg (feedstock) per day per larvae; since when fed 200 mg/day those larvae's weight was not statistically greater. However pg. 122 Table 3.1 does break down the difference in protein content & fat (among other things) for larvae fed different amounts (mg) per day; thus, at 200 mg/day feed/larvae they had greater protein & less fat than otherwise. On the other hand pg. 124 Table 3.13 clearly shows that at the rate of 200 mg feed/day/larvae the waste reduction is significantly less than at lower feeding rates.

  • @Moofisilla

    Interesting idea, looking for a way to let the production of the two insects compliment each other. Just off the bat I can imagine being stuck with the beetles used for breeding after they have produced the eggs and not knowing what to do with them. What you proposed might have a solution for this dilemma.


    As always your contribution is extremely informative and valuable. Such a thorough and simple description for the defattening process. Recently, in a separate article I have read that by just using high mechanical pressure the fat can be extracted (not sure how effective it is).

    I downloaded and read the thesis. It is interesting how important feed depth was. Seems like one must strive for a depth of 5 cm with blended feed. If the data presented by the thesis on the different provision sizes aka densities were accurate and true then this can be quickly translated to a farming setting where 125mg density is used in rearing and the 200mg density or more is used for the future broodstock taking into account that the environment conditions must be optimal.

    I'm looking into finding the right organic waste available in my area. We have quite a lot of agricultural waste but finding the perfect waste blend will require some trial and error. The table in the thesis that shows the composition of bsf feed will be of great help in this.

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