toad stalking black soldier fly larva

In my previous post I described how a person can develop something like affection for a colony of black soldier fly larvae (Hermetia illucens). If that’s the case then why do i enjoy feeding the grubs (larvae) to other animals? A big part of it is the same pleasure I mentioned that you get from feeding animals in general. There is just something satisfying about watching animals eat, especially when you provide the food. I don’t feel like I’m being hypocritical, let me explain…

Maintaining a natural balance

Black soldier flies lay from 500 – 900 eggs in the few days they live as adults. In nature the vast majority of these eggs don’t live to reproduce, if they did it would lead to an unbalanced population. Assuming that there is one female BSF for each male, then the proper balance would be maintained if two of the several hundred eggs survived to reproduce. That’s a high rate of loss, just as nature intended.

In an uncontrolled setting the BSF would be heavily preyed on by frogs, toads, birds, lizards, little furry things, etc. Protecting the grubs in a container serves us because we can employ them to process our food waste, but it does result in a much larger number of larvae surviving to the prepupal (last larval) stage. By feeding most of these larvae to pets, pond fish or wildlife we maintain a more natural balance.

toad eating black soldier fly larva

Enjoy feeding local wildlife

By keeping a BSFL bio-composting unit you convert what would have been nasty landfill into a nutritious, and I assume delicious, source of food for your local wildlife. As in nature you can allow a small number of larvae to pupate, but you also have a great opportunity to enjoy feeding critters.

There is a long list of birds that love to eat BSF grubs, and there are feeders that make it relatively simple. You can search for information about feeding mealworms to wild birds and simply use black soldier fly larvae in place of the mealworms. Check the link below for more information.

Web search: “feeding birds mealworms”

As you might guess from the photos in this post I often feed the local toad population with BSF grubs. One nice thing about feeding the toads is that they’ll eat while you’re fairly close to them. I’m sure it’s serious business to the toads, but it’s still fun to watch the way they “stalk” the larvae. Keep in mind that some of the larvae I offer to the toads and other wildlife will escape and survive.

[youtube width=”400″ height=”325″][/youtube]

feeding, black soldier fly, larvae, flies, toads, frogs, pet, lizard, wildlife, hermetia illucens,

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34 thoughts on “Up the food chain – feeding black soldier fly larvae to other animals

  • July 4, 2008 at 1:05 pm

    I can’t believe that 1) this site exists and 2) that I found it!

    I own and our chickens LOVE to eat BSF larvae!!

    I linked to this blog in my thread here where I have a picture and a video.

    Oh, related to this food chain post by Scott: I made a new game involving BSF larvae:

    Keep up the good work Scott!

  • July 4, 2008 at 1:23 pm

    Thanks! I’ll spend some time on your site when I get a chance. I appreciate you including a link to my blog on your forum. I added your site to my Friends and Colleagues section.

    Please let me know if you get a good quality video of your chickens eating BSF larvae, I’ll add it to my videos.

  • September 23, 2008 at 12:29 am

    Bizarre – today, checking over my worm farm, I found a heap of what I now assume were BSF pupae. I’ve seen them before, but assumed they were generic fly pupae, and I’m ashamed to admit that I biffed all I could find out onto the drive for the blackbirds to eat (oh well, they’re nesting, so at least it went to a good cause).

    And now I find this site! I shall definitely be checking back regularly – growing extra protein sources for my chooks is becoming a source of fascination.

    Although I don’t think importing a Biopod to New Zealand is going to be happening any time soon …

  • September 23, 2008 at 11:53 am

    Hello ChookeNZ,

    I’m sure your chooks (chickens to us :) ) will appreciate the larvae. If you’re even a little bit handy you can make something to raise BSF with. Also there are BioPods in AU so maybe you can get a unit without the shipping costs being too high.

    You may find some good info in this thread at BackYardChickens: LINK My member name is “bsflarva”.

  • June 22, 2009 at 2:25 pm

    I bought a BioPod several weeks ago and stocked it with a few hundred BSF larvae. Several have migrated out of the Pod and into the collection bucket. I’ve been collecting the prepupal larvae and placing them in a saucer about 15 feet from the Pod in the hope they will emerge as black soldier flies and lay eggs in the Pod. So far none of the larvae have emerged as flies. I’ve seen no shed “skins” and I’ve seen no egg clusters inside the Pod.

    How long does it take for the larvae to metamorphose into flies? I’m in Southern California and the weather is usually mild day and night.

    If I left the prepupal larvae in the collection bucket would they metamorphose into flies and find their way from the collection bucket back up into the Pod?


  • June 25, 2009 at 6:42 am

    Hi Gary,

    My main concern is the prepupal larvae (mature grubs) that are in the saucer. I’m worried that they will either be eaten by wild animals or that they will dry out and die. I recommend putting them in a bucket or some other container with a lid and keeping them out of direct sunlight, just like with a BioPod. Naturally the container must have vent holes for air and for providing an escape route for the newly emerged adults. I vent the bucket I use on the sides so that any rain that hits the bucket won’t be as likely to flood the grubs. I put one or two inches of sawdust in the bucket which seems to encourage the grubs to pupate.

    I don’t recommend leaving the mature grubs in the collection bucket. Most likely they will emerge but they will not find their way out. Of course you could open the collection bucket everyday to let them out, but being trapped for up to 24 hours would be stressful on a creature that only lives for a few days.

    One thing about observing eggs in the BioPod is that the BSF females don’t always lay in the egg disc. Often they will lay their eggs randomly on the inside walls of the BioPod. Here’s a photo of eggs laid in the eggs disc:

    Black soldier fly eggs on egg disc

    I once timed the pupation process of BSF and found that it took over three weeks for those grubs to pupate and emerge as adults. I’m sure that the timing will vary depending on several factors including the condition of the grubs, humidity, temperature, etc. I created a post about it which you can find here.

    I hope that helps, good luck.

  • July 30, 2009 at 8:32 am

    I am confused about feeding animals waste to the BSF grubs . THe biopod site says NOT to use pet waste and then feed the grubs to other animals. But everysite I see , including the research done by NCSTATE uses them for just that purpose. Using BSF to process poulty waste and then feed the grubs back to the chickens. I raise rabbits and want to process the pellets( poop) with the BSFgrubs and then feed the prepupea to my chickens? Are they concerned about cats and dogs only? I hope some one can help my confucion.

  • July 31, 2009 at 8:11 am

    Hi sonya,

    The reason ProtaCulture says not to process pet waste is because of liability issues. Handling feces is more risky than handling kitchen scraps and in our society lawsuits are very common.

    When feeding manure-raised BSF grubs to animals there is a basic rule that Robert from ProtaCulture (BioPod company) has given. BSF raised on manure from one type of animal (mammal, reptile, fowl, fish, etc) should not be feed back to that same type of animal. Accordingly you should be fine feeding BSF raised on rabbit manure to your chickens.

    The information above is based on feeding live or unprocessed BSF to animals. I believe that if you process the BSF sufficiently, as was probably done in the studies you cited, it’s acceptable to feed them back to the same animals that produced the manure that fed the BSF. The issue is most likely about pathogens like parasites, bacteria and viruses, so by sterilizing the BSF the risk is eliminated and they may be feed to the same animals that helped produce them.

    I’m not a biologist so please don’t take my comments as fact. (Yes, that was a disclaimer 😉 )

  • July 31, 2009 at 11:08 am

    I stumbled on the BSF under my rabbit hutches and then in a huge palstic bin that I had raised chicks in and put outside. They seem to be thriving in the bin. But it is getting liquidy and I need to know what to do. I have ordered a Bio Pod but don’t want to lose this colony before it gets here. I really don’t want to cut a hole in the bin to drain it. Would a layer of pine shavings work to keep it dry. I put some corrigated plastic in and there are already eggs. Any ideas of how to keep them going like this a few weeks?

  • July 31, 2009 at 6:07 pm


    Since you have BSF laying eggs you have little to worry about. If you don’t like the consistency of the waste in your temporary BSF bin then you can simply move the eggs to a new container and start fresh.

    In general avoid overfeeding the colony, especially in the beginning. Anything you feed the BSF grubs should be gone in a day or two assuming it’s soft enough for them to eat.

    If you want to dry the waste in your current bin you can add old flour mixes, dry cereals, and stale or moldy bread if you have them. I’ve even added a small amount of sawdust before, but not from pressure treated lumber because it’s toxic to insects. If you have a lid on this bin you can leave it off during the afternoons to aid evaporation. Of course you don’t want to let any rain get in. If it begins to get stinky it’s an indication that you have some anaerobic bacteria which isn’t desirable. If it were me I would add some dry cornmeal in that case. I hate to feed good food to creatures that thrive on waste but I would do it to prevent the colony from becoming more unbalanced. As you work more with the BSF you’ll learn how to prevent imbalances like this.

    The latest thing we’ve learned about draining liquids in a BioPod is the use of coconut fiber (coir) as a pre-filter of sorts. Lining the bottom of the BioPod with an inch or two of coir will help keep the filter medium in the drain from clogging. I had already started my colony this year when I learned this but I think I’m going to remove the compost from my unit, install some coir, and then put the compost. Coir is available in large discs for lining wire hanging baskets, or in bricks which can be shredded. I’m not sure which is the best one to use but I’ll write a post about it when I find out.

    Thanks for sharing, please keep us posted. :)

  • August 5, 2009 at 12:22 am

    I am very new to BSFL. In fact, I stumbled on to them by accident while going through my composting worm bin. After researching them, I am now very interested in feeding them and learning about them. I know that they like starchy items, but what should I feed to my composting worms so that the BSF doesn’t lay eggs around my compost worm bins. I think I answered my own question! I think I should concentrate on cardboard and grass clippings for the worms and kitchen waste for the BSFL. Doing this will cause the small amount of Larvae in my worm bins to decrease and eventually go away while keeping up the population of Larvae in the BSFL bin. I will eventually invest the money for the Biopod that is being marketed online. Do they come in different colors than grey? I live in Tyler Tx. glad I found this blog!! Thanks for any input!!

  • August 5, 2009 at 10:23 am

    Your answer is correct Bill, the BSF won’t target high cellulose items like grass, leaves and paper. Also, your worms will do very well digesting the BSF castings you collect.

    I just want to clarify your comment about starchy items being the preferred food of BSF. Grains, fruits and vegetables are the favorite foods for BSF, but they can also consume meat and dairy products as well as most types of manure. Animal products should be given on a limited basis though as indicated in a study by BioSystems Design:

    “While the larvae consumed all types of vegetable foods (both natural and processed) they had a limited ability to remove animal products (meat and fat) even when these represented less than 10 percent of the food available in the laboratory.” (1)

    Confirmed: A BioSystems Design Study with Universidad de la Salle and Victoria Gutierrez Baron and Natalia Sanchez confirmed that optimum feed for BSF was comprised of 50% vegetable matter and 50% fruit matter, even when compared to a feed of 47.5% vegetable matter, 47.5% fruit matter, and 5% animal products (meat/fat).


    This year I’ve been feeding my colony a large percentage of fresh whole fish and it seems that fish might be an exception to the rule above. Perhaps the lower fat content of fish or the speed at which it breaks down is a factor making the result different than that from mammals and birds.

    BioPods don’t come in more than one color at this time but I’m sure there are paints that will adhere to them. I think a camo colored unit might be popular. Now that I think about it I may write a post in the future titled “Pimp my BioPod”. :)

    Anyway, thanks for the great comment and please keep us posted.

  • August 5, 2009 at 10:46 pm

    I just pimped my ‘pod to look like the “Mister Fusion” from Back to the Future.

  • August 6, 2009 at 8:17 pm

    Pics or it didn’t happen. 😀

  • August 11, 2009 at 11:04 pm

    I’m calling the ProtaCulture law firm. 😛

  • August 29, 2009 at 1:20 am

    Funny I should stumble across this page. I’ve actually been thinking about composting, though haven’t started yet. Unfortunately for me it seems I’ve got my steps all backwards! I think I have an invasion of BSF in my house. A few days ago I found two large flies at my kitchen window. Could not identify them at the time, but thought it curious because I never saw them fly in the door. Today I found one “maggot” then three more as the night went on. I collected the second specimen as I realized this may be an invasion upon my kitchen, and did some online research. What I found are actually the Puparium. As I researched it all fit together. The big, unfamiliar black flies and the weird maggots…it’s the growth process of the BSF happening right before my eyes and inside my house. I can’t figure it out.

    I can’t pinpoint an environment that would be conducive to the eggs & larvae except possibly one location. We just brought a new dishwasher into our home. It was sitting in a friends garage for a few months. Could it be that the BSF laid eggs under it or within the disposal components of it? We do not keep decomposing food or feces in our home, so…where could the larvae have survived? Should I expect 500 mature BSF to fill my house within the next few days and then have more eggs laid in my home?! Any knowledge on this topic would be helpful! Thank You.

    Very enthusiastic about composting after reading through the posts! Thanks.

    • August 29, 2009 at 6:50 am

      Hi Patricia,

      Neat story. No, I don’t think you’re looking at an invasion of 500 BSF. I takes a lot of food to grow a BSF larvae and doubt that they developed in the dishwasher, but I agree that the pupae probably came in that way. After maturing on a food source BSF grubs can crawl up to 300 feet in search of a dry, protected pupation site. I think the dishwasher which had been stored in your friends garage served that purpose for the BSF you’re seeing. If by chance a male and a female BSF emerge from pupation in your house I doubt they would mate inside, and if they did I doubt the female would lay eggs in your house (no decomposing food or feces). It’s more likely that the adult BSF would spend their short lives against a window pane trying to get out unless you catch them and release them. :)

      It’s good to know that BSF are present in your area if you do decide to culture them. I should point out that “composting” isn’t a completely accurate term for processing waste with BSF. Traditionally, composting refers to allowing vegetable matter to decompose with bacteria as the main agent in the process. I use the term “biocomposting” to signify the difference when using BSF, but an even better term is “bioconversion”. When you use BSF to consume waste you’re actually converting food waste into BSF larvae (which I often refer to as grubs).

      I’m glad you learned about BSF and I hope you try working with these beautiful bugs.

  • September 4, 2009 at 9:43 pm

    I raise roaches for my lizards to eat and today I found these strange looking larvae in my roach bin which I think are BSF grubs, I also found a fly which looks like the one on this site. Now to my question , are these grubs called by another name like phoenix worms.

  • January 16, 2010 at 8:52 am

    Wow, this is quite unusual. At this stage I don’t think I’m about to start breeding maggots! (Feeling nauseous at the prospect!) I was actually researching fly traps to get rid of the buggers, as the moment one of my chooks does a dropping, boom, the flies descend for a feed.
    This is a whole new world….!

    • January 16, 2010 at 11:17 am

      Hi Aimee,

      Feeling repulsed by flies and maggots is natural, but usually people loose that feeling about black soldier fly larvae as they work with them. There are over 100,000 species of flies and while many spread human diseases BSF do not. The reason BSF aren’t vectors of human diseases is due to their life cycle and habits which are different from pest flies. Black soldier fly adults (winged stage) don’t feed, they only live a few days to mate and lay eggs. Since the adults have such short lives and don’t eat it’s relatively rare to see one. The flies that you see so quickly on the chicken manure are probably another species. The good news for people who have BSF in their area is that when waste is inhabited by harmless BSF they typically limit or completely eliminate pest fly reproduction in that particular waste. In other words, the more BSF larvae there are on your property, the less pest fly species you will have to contend with.

      Since you keep chickens you have a very good reason to encourage BSF larvae production; the chooks love to eat them and the larvae are very nutritious.

      Thanks for commenting and I wish you well with your birds and bugs. :)

  • January 30, 2011 at 12:17 pm

    Hi Jerry,
    My sister who lives up north would like me to ship up some BFS grubs for her to feed her lizards ,but what kind of subtrate should I use in the shipping process. I was thinking maybe oat bran or corn meal.Do you think this could work or should I try something else

  • May 9, 2011 at 1:07 pm

    please, what can be done to reduce the invasion of maggot in a poultry farm?

  • June 30, 2012 at 8:56 am

    How do I harvest the BSF castings to feed to my worm population?

  • August 10, 2012 at 10:39 am

    I am interested in growing black soldier fly for fish in an aquaponic system. If I get fruits and vegetables from someone and I don’t know where they originally came from, is there any worry about pesticides and herbicides contained in the larvae. If there’s a possibility I am not going to want to feed them to my fish.

  • August 25, 2012 at 8:48 pm

    I am doing some research to find out more about BSFL use in composting a large amount of culled fish. These fish will come from a highly eutrophic water body laden with Cyanobacteria (blue-green algae) and may have high concentrations of the toxin in their flesh. I have done some reading about the ability of BSFL to neutralize bacteria and viruses but haven’t found anything to determine if they are good for this purpose as well. Any info or links would be appreciated.

  • November 14, 2012 at 2:59 pm

    my name is juan carlos urzola, i live in colombia south america,
    i was tryin to catch black soldier flies to start a poultry exploitation,
    so i put to rottening a batch of grinded corn inside a bucket as black soldier flies farmers do in north america,
    after a few weeks i ended up with a LOT of yummy larvae.
    so i isolated a few in a closed plastic box, to see the adult of this larvae
    , and then i discovered that i didnt got black soldier fly but a green fly
    im not a scientist but i think is a calliforidae,

    what do you think about growing them instead of the black soldier fly?
    is that calliforidae larvae bad for the digestive system of the chicken?
    do they transport diseases to the final human consumer?

    i know the caliphoridae adults are a vector for diseases.
    what do you say about larvaes,
    do you know any study about using them as chicken food?

    than you so much for your time!

    • November 14, 2012 at 3:09 pm

      Hola Juan Carlos,

      I don’t know about this other species, but in general I’ve read that no other fly has the same properties that make BSF good to culture. It would be nice if there was another fly that was good for this type of process. If you learn something please share it with us.


  • November 14, 2012 at 6:33 pm

    this guys from sud africa are radical , they are using the domestic fly
    they raise on human poo, and blood. they have a huge industry

    read the article they affirm that you can give shit fed larvae to chickens ,
    so i think my green metallic fly grew on rotten corn won `t be harmful neither
    i saw another video on japan about the domestic fly, they have them in a enclosed cubicles
    they dry the larvae and grind it to sell it,

    im gonna search for this japanese vid and post it here…

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    I as well am an aspiring blog writer but I’m still new to the whole thing. Do you have any recommendations for rookie blog writers? I’d genuinely appreciate it.

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