What Is Black Soldier Fly Larvae?

Black soldier fly larvae (BSFL), Hermetia illucens, is the immature form (larvae) of a naturally occurring common fly in many geographical regions throughout the world, including: Africa, Europe and Australasia

Black Soldier Fly Larvae
Black Soldier Fly Larvae – Wikipedia

In recent years, the agri-world has really been buzzin’ about this little helper for one reason, or another…

Thanks to recent enquiry via our ‘Ask A Question’ web page…

We decided to take a deep dive into what makes Black Soldier Fly such a popular topic all of a sudden!

What is Black Soldier Fly Larvae so popular?

Black Soldier Fly Larvae (BSFL) offers 2 significant economic benefits to man as commonly quoted, by such institutions as:

University of Florida – Featured Creatures: Entomology & Nematology

“…not only reduce livestock waste [1], but also generate a food source for fish and other animals [2]…45,000 larvae will consume 24 kg of swine manure in 14 days…a good source of oil and protein for animal feed.”

Further reading: Introduction To Black Soldier Fly – Uni. of Florida

As stated in the article above, the Black Soldier Fly Larvae is prolific at converting livestock waste into fertiliser.

The adults fly interestingly enough don’t have much of an appetite other than nectar grazing, but are metabolically sufficed up to 8 days with water alone & fat reserves built up during the immature larvae stage.

“…black soldier fly larvae are insatiable feeders. As adults, they do not need to feed and rely on the fats stored from the larval stage (Newton et al. 2005).”

Some Black Soldier Fly Larvae facts!

The average black soldier fly larvae weighs around: 0.15g and roughly 45,000 larvae will convert 24kg of swine manure in 14days.

That’s approximately, 6,750 g of BSF larvae or 6.75kg…

Or, a population of larvae converting 3.5 times or 350% their equivalent mass/weight in swine manure into fertiliser within 14 days…

Or, BSF larvae converting 25% their equivalent mass of swine manure per day (24hrs)…

“…[manure] conversion rate stands at about 50% reduction of livestock manure in Black Soldier fly larvae reduced 55 kg of fresh manure dry matter to 24 kg of digested manure dry matter within 14 days (a 56% reduction). No objectionable odor could be detected from the end product of black soldier fly digested manure. Black Soldier fly larvae reduced the concentrations of nutrients of fresh manure, generally, from 40 to 55%.”

Further reading: Soldier Fly Swine Manure Management University of Carolina

Take a look at this video introduction to BSFL farming by Sandec Eawag, called:

How to Use Black Soldier Flies for Biowaste Treatment

Black soldier fly larvae residue as a fertiliser

Firstly, the residue after larvae conversion is quoted to be of:

  • “…no objectionable odour.” (Newton 2005).

This is an advantage for storing residue onsite at your farm or smallholding.

Research also suggests: the residue produced is:

  • …a valuable soil amendment, possibly somewhat similar to compost.” (Newton, 2005)

In tests comparing growth rates of Sudan grass commercial potting soil mix vs. black soldier fly residue from swine manure, the following was seen:

  • “Sudan grass growth response indicated by dry weight was best for 5% black soldier fly digest in both sand and clay soils.” (Newton 2005).

Does Black Soldier Fly Larvae convert livestock manure into agricultural fertiliser?


Take this case for example in the USA where nutrient management programmes imposed by government agencies on farmers estimated the following running cost increases for farm compliance with their nitrogen soil standards, as cited by US Department of Agriculture study by Ribaudo et al. 2003::

“…estimated the additional cost of complying with nitrogen standard CNMPs in the Mid-Atlantic region (with a 50% willingness of neighboring farms to accept the application of swine manure to their land) to be $11 per animal unit (AU) for farms with fewer than 300 AU, $2.25 per AU for farms with between 300 and 1,000 AU…”

But, what’s the reasoning behind such measures?

In America, the USDA has imposed measures on livestock rearing farms which through poorly managed animal feeding have contributed to water pollution:

“…site-specific comprehensive nutrient management plans (CNMPs) to minimize potential adverse impacts on water quality and public health, and to accomplish this within a 10-year implementation period…”

Importantly for the focus of this article, the following comment was made re: Black Soldier Fly Larvae conversion of livestock manure as a potential cost-saving solution for farmers under the USDA CNMP:

“…The additional costs for complying with a CNMP would therefore be reduced significantly if black soldier fly manure processing were used.”

Black Soldier Fly Larvae as dietary protein for livestock

According to leading researchers, BSF larvae does possess:

  • relatively high proportions of crude protein & other essential dietary minerals/vitamins for livestock

“…BSF larvae contain high protein levels (from 37 to 63% dry matter; DM), and other macro- and micronutrients important for animal feed…”

Further reading: Nutritional value of the black soldier fly (Hermetia illucens L.) and its suitability as animal feed – a reviewWageningen University & Research

Yet, it is recommended that BSF larvae ought not to entirely replace a commercial livestock diet. Why?

“…because high or complete replacement resulted in reduced performance. This is due to factors such as high fat content (from 7 to 39% DM), ash (from 9 to 28% DM), and consequences of processing…”

Further reading: Nutritional value of the black soldier fly (Hermetia illucens L.) and its suitability as animal feed – a review – Wageningen University & Research

However, in a partial dietary replacement strategy, BSFL (black soldier fly larvae) present significant livestock feed cost savings in countries which commercial feed ingredients are generally imported:

“…Ghanaian feed industry imports over 90% of its protein hence making poultry and fish feed very expensive…”

Further reading: Potential of the black soldier fly (Hermetia illuscens) as a replacement for fish/soybean meal in the diet of broilersUniversity of Energy and Natural Resources, Sunyani, Ghana

Where used as an alternative protein feed source, the relatively lean BSFL farming operational model offers significant cost efficiencies – making BSFL a profitable supplement:

“…BSFL can successfully be used as a replacement of soybean and for partial replacement of fish meal to reduce cost of poultry production…”

Further reading: Potential of the black soldier fly (Hermetia illuscens) as a replacement for fish/soybean meal in the diet of broilersUniversity of Energy and Natural Resources, Sunyani, Ghana

Having said this…

There are some studies which claim the exceptionally high crude protein content of BSFL touted by some studies may be a little inflated according to nitrogen-protein conversion ratio.

In studies, such as this one as published by Chinese Roots Global Impact, results show very little difference in broiler weight and/or musculo-skeletal development when…

Up to 8% of crude protein of diet is substituted with Black Soldier Fly Larvae:

Coq de la race ardennaise
Coq de la race ardennaise – Wikipedia

“…Weekly weights of Ardennaise chickens fed a commercial standard feed in which 8% was substituted with whole de-frozen larvae were slightly higher than those of control chickens. All the other measurements were not statistically different between larvae-fed and control chickens, including fatty acid profiles.”

Further reading: Performances of local poultry breed fed black soldier fly larvae reared on horse manureAnimal Production Department, Faculty of Veterinary Medicine, University of Liege, B-4000 Liege, Belgium

Research consensus would therefore support either supplementing commercial feed rations with a BSFL addition or…

Substituting relatively moderate amounts of crude protein content of livestock feed with BSFL.

Livestock performance should be unaffected at moderate levels of use of BSFL in feed – if not only slightly improved when compared with a commercial feed only ‘control’.

The main farming advantage therefore should be economic (e.g. savings against direct cost of sale, for feed ingredients).

Black Soldier Fly Larvae vs. housefly maggots as a livestock feed?

Whilst both larvae of BSF and housefly seem to convey considerable crude protein & other nutritional (fatty acids, minerals etc.) benefits to livestock, in particular poultry…

Further reading: Utilization of house fly-maggots, a feed supplement in the production of broiler chickensNational Institute of Animal Science, RDA, Suwon – 441 706, South Korea

An important note to add is:

Nutrient levels in both larvae will vary depending on the substrate the feed on.

Whilst on a nutritional value scale – BSF and housefly larvae are nearly inseparable…

They do critically differ in one important area:

The critical difference between the use of BSFL vs. maggots as a livestock feed is:

“…[BSF] larvae of the fly is capable to reduce the microflora of the manual. This special larvae activity reduces the harmful bacteria such as Escherichia coli and Salmonella enterica. It is a natural antibitiotic treatment comparable to the cleaning of wounds by the fly Lucilia sericata…

Whereas with housefly larvae:

“…maggots are the larvae of the housefly Musca domestica. This housefly is widely involved in disease transmission. Therefore, before using maggots as feed, bacteriological and mycological research…”

Further reading: Insects as feed for livestock and fishFAO

Although in many African countries and regions, maggots have always been used as a component of poultry feed to no major detriment…

It is generally advised, because of potential for disease transmission by housefly…

That this approach is thoroughly bacteriologically researched, before considered for commercial adoption.


So to round up…

Black Soldier Fly Larvae is indeed a viable protein substitute for inclusion within a livestock feeding strategy – as verified by leading global scientific research institutions.

There are some mild livestock performance benefits noted against commercial feed, especially in the area of weight gain…

Most notably when blended with fish meal in a poultry farming regimen.

Economic benefits of rearing Black Soldier Fly Larvae…

Especially when used in the context of bio-waste management offer real profit incentives to farmers seeking to reduce feed costs through alternative ingredients.

Also, regions within which farmers are targeted on bio-waste management practices and soil nutrient quotas may also incur cost saving benefits.

Compared with other types of insect larvae, such as maggots (housefly larvae)…

BSFL seem to provide advantage in their riddance of Salmonella, E.Coli and other pathogens from their feed substrate.

Rearing BSFL can be performed relatively cost effectively…

And to great economic advantage to a mixed purpose livestock and crop production farm model.

Whilst there are clear researched plus points to utilising the waste conversion traits of BSFL…

Not every country has immediately embraced the practice of rearing the BSFL…

Many tentatively keeping a guard whilst watching developments for further more persuasive research outcomes.

Research well and consider your steps.

Do you have intentions on rearing BSFL for commercial use and would like further information?

Ask us here.

Are you considering using Black Soldier Fly Larvae as a feed supplement for your livestock?

Get advice on proportions and formula here.

Have experience in BSFL farming? 

Share with us in the comments below.

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