The Black Soldier Fly Challenge


I believe black soldier fly larvae represent the most logical method for dealing with the constant stream of putrescent waste that humans create. Putrescent waste is anything that gets putrid (rots) and is mostly wasted food. Like all skeptics I immediately started looking for the negative aspects of processing this waste with BSF, and while they aren’t magic it’s hard to imagine a much more efficient solution to a growing problem.

adult bsf


The process of feeding organic wastes to black soldier fly larvae is called bio-conversion. That’s because the process doesn’t exactly eliminate the garbage, it converts it into BSF larvae. Rotting garbage is a liability and BSF larvae are a valuable asset. You can read more about bio-conversion HERE.

BSF prepupal larvae

Generally accepted data about black soldier flies and larvae

  • They are not associated with the transmission of diseases
  • They don’t bite or sting and they avoid human habitats
  • Their presence in waste deters or even eliminates house fly reproduction in that waste
  • Larvae rapidly consume almost any organic waste except for high cellulose items like yard waste
  • Larvae reduce the volume of household food waste by up to 95%
  • A 2 foot (60cm) container of larvae can process 5 lbs. (2.3kg) or more of household food waste in 24 hours
  • When larvae mature they will self harvest using a simple ramp system
  • Live larvae are very nutritious and are readily consumed by many different animals (pigs, chickens, reptiles, fish, etc)
  • Meal made from dried larvae is roughly equal to Menhaden fish meal, a valuable and widely used ingredient in animal feeds.

The challenge

I’m making the claim that bio-conversion of putrescent waste with BSF larvae is the best way to deal with the constant stream of rotting waste that goes into landfill. The challenge is simple, state any significant problem that might be caused by using BSF to convert our organic garbage into nutritious animal feed or high quality products for industry such as bio-fuels.

Let’s not wait

Burying our food waste in giant rotting mounds is ridiculous given the elegant solution represented by bio-conversion with black soldier fly larvae. The technology already exits and represents the essence of sustainablity. What in the world are we waiting for?

  •  Posted by at 8:53 am

  17 Responses to “The Black Soldier Fly Challenge”

  1. The only question I have about using the self-harvesting BSF composters is about the effect this harvesting has on the wild BSF population levels. I’m interested in BSF larvae as chicken feed. I compost with red wiggler worms and much prefer the idea of self-harvesting feed. Does giving the wild BSF females a place to lay their eggs, catching the mature larvae, and then using them as feed reduce the levels of helpful BSF in the ecosystem? I don’t see how it couldn’t since the females are choosing to lay eggs in the composters which will ultimately feed their larvae to my chickens instead of them laying their eggs in a dung pile somewhere to make more helpful flies for the next generation.

    Any thoughts on this would be helpful. I don’t want to feed generations of helpful insects to my hens to the detriment of my farm’s ecosystem.

  2. Hi Jesse,

    I do not believe that maintaining a BSF colony in this fashion will have a detrimental impact on your wild population. In fact, since the systems I blog about here rely on reproduction by free ranging adults it’s in your best interest to increase the wild population. These systems contain the larvae, but the adults remain wild.

    I’ve been told that the male/female ratio for BSF is roughly 1 to 1. Estimates for egg production from a single female are 500-900, or an average of 700. If each pair of BSF adults produces 700 offspring then to maintain a stable population (no increase in size) 698 of the 700 eggs produced must not survive to reproduce. Only two adult BSF need to survive and reproduce for each 700 larvae to maintain the population. I have always promoted the practice of allowing a small percentage of larvae to pupate and emerge as adults. I usually suggest that while people are initially building up their colony that they minimize the amount of larvae that are used as feed. Once the colony is the proper size for your goals I recommend allowing 5 or 10% of the larvae to survive to adulthood. The actual numbers will vary for each situation, but with experience you’ll get a feel for what size colony is necessary to support the amount of feed you wish to produce. As the estimates above indicate; in nature the survival rate to adulthood is much less than 5-10%.

    My brain isn’t functioning very well this morning so if you still have questions please feel free to ask.

  3. Hi,

    I am looking into BSF for a larger scale production on our ranch, for feeding a couple hundered chickens and about 10 pigs. I was wondering if there is any research ,you know about, for this larger scale? Is it possible, how would I go about starting an operation like this? Any info you can give me would be great.


  4. Hi I agree with everything Jerry says except for the ratio of males to females. From a couple studies I looked at, it appears in one study that males out number females 2 to 1. In another study they divided them into Male:female:sexless. I have also seen a study that said females were 11% larger than males on average. What that means to me is that there are more males/sexless than females. I chop up the larvae for my fish and so I usually pick out the larger ones to spare assuming these are the one that are likely female. I also gather a random hand full to spare as well… I would hate the females not to have any suiters :) . The only thing I don’t know is if a male can mate more times than one. I have not seen anything on this.

    My operation is small scale. I only harvest between 100 and 300 larvae a day right now. Most of my input is fruit scraps from a fruit stand. My system gets a lot of water, but it seems to work.

  5. [...] soldier fly larvae are welcome residents of compost piles designed for bioconversion, the process of turning decomposing matter into [...]

  6. the digestor and the breeding are two different aspects
    the digestor does not work without insects, insects need organic matter to develop and live.
    one should have both elements to close the cycle

  7. Our compost got invaded (no better word) with black soldier fly larvae. Our initial reaction was, “what the heck are these?” They seemed to be eating the garbage so we let them be. There’ll be millions (approximate number) of them around next year from our compost. I hope they lay in our compost again; maybe I’ll try fishing with them. Thanks for the article.

  8. charles where are you located?

  9. I am a pretty new compost-y pal and recently noticed a large number of these larvae in my compost. Their arrival coincided with my mini tumbler ceasing to smell (too much green and not enough brown) which I am thrilled about. My kids are fascinated and love to feed our little” Grubbies” kitchen scraps. My youngest daughter thinks they look like little armadillos. My oldest is conducting some experiments to see if they might be a valuable addition to our school composting program. I must say I am completely grossed out by maggots but these little dudes are really charming and the way they eat is amazing!! Thanks for this super helpful blog.

  10. Hello. I am pleased to report that I purchased a Pod this spring. Currently I am producing a pint of larvae a day for my chickens. It has been somewhat of a learning curve to maintain production, just as keeping any kind of animal involves a challenge.

    The larvae that I purchased with the Biopod soon died, so I had a dead Pod. I was disappointed but didn’t have the time to figure out what to do about it. One day walking in the woods, I spied a dead raccoon that was infested with maggots. The stench was overwhelming. I looked closely and saw soldier flies crawling on the ground near the carcass. I walked home, thinking about the possibilities, took a deep breath to rev up my courage. I had a 5 gallon bucket with a lid, found a small shovel, and put them in my car. I went back and shoveled the carcass into the bucket. At home I emptied the bucket contents into my Biopod.

    In the next few hours, the stench of carrion was becoming intolerable, and I knew my neighbors would complain. Something had to be done. I picked up the Pod and dragged it up a ladder to the top of an old tree house used by my kids when they were growing up. I had dreams that night of things crawling all over me, and was seriously afraid that I had gotten mites or lice or something from contact with the Pod filled with raccoon carcass. However, I didn’t die, and didn’t get sick. I kept the operation a secret from my husband

    Three days later I went up to check the Pod and found to my utter delight, a good number of grubs in the collection bin. Furthermore, the stench was almost gone! I didn’t move fast enough to replenish the Pod with new organic matter for the larvae to feed on, so the Pod dried up, after providing me with grubs for two days. However, I soon found soldier flies around my compost bucket, so emptied the bucket into the Pod, instead of onto the compost pile. I added 2-3 lbs. of alpaca manure on the top to cover the waste and keep odors to a minimum. I have had a steady supply of around a pint of grubs a day for the last two weeks.

    I do think that soldier flies are a great solution for noxious waste, but learning how to cultivate them takes some time and experimentation. It also takes nerve.

  11. Thanks for the interesting observations Sarah,

    While it was brave of you to handle the dead raccoon, it really wasn’t necessary. If it was me, and I wanted to jump start a BioPod I would have only taken some larvae, not the raccoon. BSF larvae give off a very subtle scent that attracts BSF females looking for a food source to lay their eggs near. You could have simply added the larvae to some “clean” waste like kitchen scraps and started that way. At any rate I admire your determination and I’m glad you got the desired result. You seem like someone who could add something to the discussion at our forum and I would be happy if you joined. If you’re interested just click the forum icon on the top right of this page.

    Thanks again and good luck!

  12. This is so awesome!
    I suppose i kinda made my own “bio pod” a couple of months ago and at first i wanted to gather compost for the garden when i noticed the whole thing just creeping and crawling with maggots and it gave me the heeeeeebie jeeeebies mainly because I had no clue what they were.
    After just googling larvae and checking out pictures I found your blog here and I have also spied a soldier fly.
    I basically just took a storage bin and started throwing my organic scrap in it and leaves and fireplace ashes. I also juiced for a little while which gave some good pulp. I have yet to notice a horde of flies or anything, but i also live near the woods. i sometimes leave the lid off so i’m sure the birds come and grab a tasty treat. These little suckers sure do eat through a lot of matter and i had no clue i could use them for fishing bait.
    I’m too chicken to touch them.
    I am all for composting and keeping as much out of landfill as possible. I also recycle some so it really keeps the waste to a minimum and it’s just me so it saves me 20bucks a month for waste pick up just to separate my organics and take the plastics to the recycle which is free.

    Soldier Flies are my new little heros! :)

    Thanks again for the blog!

  13. Hi Tanja,

    Thanks for sharing that. You might enjoy the forum:

  14. I got a raccoon carcass from the woods and put it in my biopod. It was so smelly, I had to put it i a tree. 3 days later it didn’t smell, so I took it down, and found several handfuls of juicy grubs which my chickens gobbled up. Then, nothing for two weeks. I saw several soldier flys in my house trying to get out the windows of my kitchen. I fondly carried them outside.

    I happened to inspect looked in an outdoor 50 gallon worm bin that was filled with alpaca manure. It was filled with soldier fly grubs! Now my chickens are happy, and one of my most popular gifts to friends in my chicken farming community is a quart of soldier fly grubs.

  15. Hi Sarah,

    I like your spirit (gathering dead critters) but I wouldn’t recommend it for most people. I would also like to say that finding BSF in your house is a little unusual. I bred hundreds of thousands of them over a four year period and only found a few in my house. Anyway, thanks for sharing with us; you might enjoy the forum.

  16. I have a worm farm, up here in tropical NT, and have been wondering what these strange creatures were, they appear in the worm tea, am interested in finding out more about these creatures.
    I am a 78 yo bloke working with the local JAWOYN and WAGIMAN people on growing “BUSH TUCKER”, am just wondering the benefits of these flies on my project, would like suggestions.

  17. Hi Kenneth,

    One of the most attractive attributes of BSF larvae is their nutritional value. They’ve been used as feed for poultry, fish, reptiles, amphibians, and some mammals. We have some information on this site and you will find a large BSF community in Australia. You might also consider joining our forum for more specific questions and answers. Enjoy!