There are more than 100,000 species of flies, but in most people’s minds a fly is a fly, period. The species most people automatically think of are the house flies, blow flies, and bottle flies. Our disdain for these pests is understandable because they are known transmitters of human diseases, but non-pest black soldier flies (Hermetia illucens) are different in several ways. The most important difference is that BSF are not vectors of human pathogens. Black soldier flies rarely go into human habitats or land on people, and the adult black soldier fly doesn’t even eat during it’s short lifespan. Now that I’ve gotten that out of the way, on to the mythbusting. :)

Swarms of black soldier flies = myth

I’m convinced that most people imagine a swarm of black soldier flies hovering around a BSF composting unit such as a BioPod. They would be wrong. I’ve been culturing black soldier fly larvae for one and a half years and the greatest number of winged adults I’ve seen at any one time is less than 10. Most of the time when I check my BioPod there are no flies near it. I don’t think I’ve ever seen one before noon (apparently they sleep in), and you don’t see them when the sun is low or at night.

In case I haven’t made my point, BSF adults (winged stage) are relatively rare. One reason is that the adults only live a few days, just long enough to breed and lay eggs, and then they die. Contrast this with house flies that live 30 days or more. In the short period that BSF spend as adult flies there just isn’t enough time for big social gatherings such as swarms.

Black soldier flies pester people = myth

Black soldier flies can’t bite or sting and they don’t eat so they have no interest in people. As mentioned above you probably won’t see many BSF adults and if you do they will usually ignore you. On the rare occasions when a BSF adult lands on me it’s most often when I’ve been handling larvae and I have their scent on my hands. They land then because the subtle scent of BSF larvae is a powerful attractant to BSF females and if one lands on me I always pause to admire this beautiful beneficial insect. To be honest, I usually refer to any BSF adults I see around the BioPod as “the girls”, because males are not attracted to the unit. All of the BSF near the BioPod will be females looking for a good site to lay eggs.

BSF larvae are pests in honey bee hives = myth

I believe the BSF page at Wikipedia was the main source of this myth. Earlier versions of Wikipedia’s page about BSF stated that “The larvae can be destructive pests in honeybee hives”. There was no reference cited (that I could see) for that statement. I’ve searched the web for evidence that this is a true statement but I have found none. Perhaps the error happened because of reports that BSF larvae have been found in abandoned beehives. That is very likely since no self respecting BSF larvae would let perfectly good beehive waste go to…. waste! This is a very different scenario than the larvae being pests.

Today I spoke with Ellen Hudson, a previous head of the Apalachee Beekeepers Association, and she was unaware of any issues caused by BSF. If there really was an issue with beehives it would surely be a concern in this region where tupelo honey is a big business and BSF are plentiful.

To be continued… solider

Tagged on:     

33 thoughts on “Mythbusting black soldier flies

  • December 6, 2008 at 8:37 pm

    As the distributor for the BioPod in Australia (we will also ship regionally) I am happy to say that BSF are alive and well in Australia. Murray’s utube clip shows a unit in operation.

    Did you know that a residential BioPod will convert 1 tonne of food wast peryear, and that a commercial unit will convert 5 tonnes of waste a year into usable protein?

    Contact us to get your units up and producing. We encourage commercial growers of larvae and are happy to work with you to get to a tonnage output stage.

  • December 18, 2008 at 10:45 pm

    do you sell biopods in australia, how much are they and do you also send the seeding kit

  • December 18, 2008 at 10:59 pm

    Hi ben,

    I don’t personally sell BioPods in Australia but David Watson of Circle Three Group does. You can find him at or phone him at 1300-76-77-78 or 61733744188. I don’t know about the availability of starter kits, but if you have BSF in your area they aren’t essential.

  • January 2, 2009 at 4:08 am

    Hello Jerry!

    Wow! I have spent all day, and I mean ALL day, reading every possible thing I could find about BSFL. The majority of it was from you!

    Thank you! Thank you! Thank you!

    We are currently in the process of purchasing a farm and are looking at sustainable, environmentally sustainable practices, with as little work from us as possible. I worried most about feeding the pigs, chickens, ducks, turkeys and geese through the winter as I’m in Canada.

    We obviously need to develope some type of breeding enclosure and keep the habitat indoors to produce the amount of BSFL we will need but I’m thinking! For now we are going to try it in our very large bearded dragon habitat. I haven’t read of anyone trying this particular set up before so I’ll keep you posted.

    You can read a bit about us on our brand new plog at

    Thanks again, Carol-Anne

  • January 6, 2009 at 11:10 am

    Your project sounds very interesting Carol-Anne. I’m sure BSF can be beneficial in some way, but I don’t think you’ll be able to use them as feed through the winter.

    There have been several attempts to breed BSF indoors and to my knowledge no one has succeeded. BSF require natural sunlight to mate, and the length of the day is important. Simply giving them a warm environment with natural light hasn’t led to successful indoor breeding in the winter months. I did hear a rumor that someone had found a type of artificial light that the BSF accept, but so far there’s no documentation of it.

    Good luck and keep us posted if you work with BSF.

  • January 6, 2009 at 12:34 pm

    Thanks Jerry. I did do a bit more research and came across the studies relating to this. There seems to be limited research. The successful indoor operations seem to be in rather large greenhouses because of the mating habits of the BSF. If I could get some BSF larvae I would be happy to experiment in the environment I do have.

    The habitat isn’t simply a warm environment. We also have a full spectrum light (replicates full natural sunlight). It’s not the average light that people have for lizards. It’s actually one used for indoor growing operations. Not a necessary thing for our beardies but one we felt they had a right to.

    However, it’s significantly more expensive, requires more electricity and is a little more fragile (will break if water is splashed on it). So, I would imagine most that are just looking to have a few BSFL as feeders would not go to the trouble, or expense. But, since we are already doing both ;}, I thought I would like to give it a try. It’s not like the BSFL would really cost me that much so why not?

    Alas, finding them seems to be the problem now so we may well need to wait until spring.

  • January 6, 2009 at 2:40 pm

    I’ve often wondered about the supply of “Phoenix worms” in the winter. I know that Dr. Sheppard of is in the southeastern US and even here the BSF just don’t breed this time of year. I suppose it’s possible he builds up a surplus in the summer and slows their development by keeping them cool.

  • January 6, 2009 at 7:54 pm

    Hi Jerry & Carol-Anne,

    I can’t speak for SE USA, but in Australia, at least from Brisbane (Nimbin for Aussies :-) ) north, we have year round breeding of wild BSF. They do slow down but continue to fly and lay eggs, even on the shortest day of the year.

    While there have been green house trials (see ~ PDF Links ~ Green House mating – factors ) that speak to captive breeding, the eggs have been sterile. They used small cages to breed the flies. Control groups outside the green house had fertile eggs, while ones inside did not.

    I understand a breeder outside the USA has created a successful artificial light in a controlled indoor environment. I would be interested to hear if you have luck with grow lights. What model and brand, intensity do you use?

  • January 6, 2009 at 8:47 pm

    David, I’m very far south in the US, just a few miles north of Florida, and I haven’t observed any egg laying in my BioPod for several months. One exception was a single female that I saw on November 11. Naturally I may have missed a few, but I also haven’t observed any small larva. We just had a few days with relatively warm temperatures so I’ll check for new larvae in 5 or 6 days.

    I’ve read that people have successfully bred BSF in enclosures that measure approximately 3m square. I’ll see if I can find a source.

  • September 22, 2009 at 4:17 am

    Found these creepy looking larvae crawling around my Northern California compost can which hasn’t been emptied in quite a while.

    Never seeing them in my area before I was nervous to touch them but left the larvae there to see what they grew into. A few days ago I was surprised to observe a large wasp-like adult fly away from the can. Its appearance made me wrongly assume it would sting or bite if aggravated.

    Glad I found your site and will definitely keep the compost can poorly maintained for these beneficial little creatures. 😉

    • September 22, 2009 at 7:13 am

      Thanks Bruce, and I hope you enjoy your BSF!

  • May 22, 2010 at 4:40 pm

    Hi there,
    Thanks for your blog! I started my first compost bin in Houston a month ago and was freaked out when found thousands of giant wriggling larvae squelching around like a scene from a horror movie. I was so relieved to find your blog and to know that they are beneficial and harmless!

    • May 23, 2010 at 3:30 pm

      Hi Adrienne,

      Welcome the BSF club! :)

  • August 15, 2010 at 1:15 am

    From Sacramento, California, USA: I’m so amazed. My impression has changed from thinking it was bad to realizing how beneficial this insect is to world! I did what I thought was composting as a child; Really, I was just burying food scraps in various parts of the yard. As an adult, I started a compost bin by just drilling some holes in an old plant bin. I started last fall and around mid-July, right after I had composted excess apricot and peach remnants, I started seeing this long black fly sitting on the side of the bin. Someone told me that he’d seen it sitting on cowdung piles growing up in India and that it was associated with “yucky” areas. So, I unfortunately stunned one to look at it. Thinking it was some sort of “yucky” bug, I buried it in the compost bin. I increased the proportion of dry leaves and soil in the bin. I continued seeing females laying eggs for 1/2 hour at a time through the side of the bin. I wanted to find more information. I watched videos on the maggots eating fish. Then I found a professor talking about how beneficial the insects are. Your blog is wonderful, how you explain that they are not going to “take over” the area or pester animals or humans. Now, I view the larvae and adults as a wonderful part of the ecology. I just wish I had a chicken!

    • August 15, 2010 at 10:45 am

      Hi Ava,

      I’m glad you discovered BSF and were able to learn about them. I have doubts that the insect seen on cow piles were BSF. I don’t believe that cow dung is a preferred food source for BSF, but more importantly, BSF females don’t normally land on waste or lay eggs directly on the waste. I’m sure there are exceptions and those could have been BSF, but there are over 100,000 species of flies so they could easily have been some other type of fly. If you can ever confirm that they were BSF or even confirm that BSF are in India I would appreciate it. I don’t recall hearing about BSF in India even though I expect they are there. A photo of a black soldier fly from India would be great.

  • September 13, 2010 at 7:49 pm

    Southern California here – I was wondering what these casing were in my compost bin. We have cut worms and I did not know if what I saw were these. Then one day – EHHH GADS!! The inside of my composter was slithering with armoured larva!!!! I am so relieved to find out that those guys are OK and not going to hurt anything. Thanks a lot –

  • September 22, 2010 at 8:08 pm

    I started a outdoor compost bin at the beginning of spring with the hopes of earthworms working their way up through the bottom of the container and eating all the fruit & veggie scraps from the garden. I guess because the sprinkler sprayed into the vent holes through the sides of the compost bin, the bin was too damp for worms so instead of worms I discovered I had BSF larvae in my bin. I had never heard of Soldier flies before but I had noticed long black flying insects around the bin. With some research on the internet I discovered they were BSF. My bin is constantly full of larvae. I live in central California where the temps are very warm. My bin is in the shade for most of the day. Thanks for your website as now my questions have been answered from reading your posts. I just wanted to add that on the Q&A section of the site there was mention that BSF don’t eat paper. I have been putting our Saturday newspaper in the bin every weekend as well as shredded cardboard & the maggots go through that stuff like crazy. The newspaper is usually gone within two to three days. I had been putting the paper & cardboard in to absorb the moisture from the sprinkler but they eat it so fast the bin is still very moist. I do have one question, as the weather starts cooling do the maggots die and decompose? I won’t be using my compost until next spring in my veggie garden.
    Thanks, Viki

  • April 24, 2011 at 8:40 pm

    Hi there. I am trying to buy one or more commercial biopods but the circle 3 website phone numbers are disconnected. I am located in Australia. If someone can help please let me know.

  • July 15, 2011 at 3:02 pm

    I set up a home made BSF Unit with a barrel in Guadaljara Mexico, I’ve harvested a couple hand fulls of larvae but what is bugging me is the fact that there are tons of other flies, and most of what is coming out from my unit are house flies and gnats and the system has been going for close to 3 months now, i’ve looked at all the picutres and am very certain that there are lots of small larvae in there but the adult harvest is minimal compared to all the other flies and beattles growing in there, what could I be doing wrong?

  • July 15, 2011 at 4:49 pm

    Hey Josh –
    Usually if your “green-waste” food material is covered enough (so you can’t see it), you will not get the other flies. I do not use the system you have, so it may a bit different, but as long as the food material is moist (not wet) and covered, the other flies are usually not there. Beetles and pillbugs, yes….

  • July 15, 2011 at 11:04 pm

    ah….what should I cover it with? and what are pillbugs? and thank you Francene, I’m actually thinking of redoing my bin or maybe purchasing a used one from biopod, buy my problem is the transportation and ridiculous cost of import taxes here, is there a model you recommend on the DIY?

  • July 16, 2011 at 2:36 pm

    Hi Josh-
    I use a completely different method. I have BSFL in a compost bin, with other compost critters. I cover the “food” material with grass (dry or freshly cut) and leaves and brown dry plant matter – but too dry and the BSFL will not survive… The air-exposed food attracts other flies and bugs. Pillbugs are “rolly-pollies” – the only crustacean that lives on land… Google “pill bug” on Wikipedia to see a picture. I do not raise BSFL for sale but only to break down my own green waste.

  • July 20, 2011 at 12:07 am

    I’ve been checking this blog from time to time for a number of months, very intrigued by this idea of the black soldier fly. Well, I noticed what looked like BSF larvae in my compost last week, and today I saw a female entering the compost, presumably to lay eggs! Very cool.

    Los Angeles County, CA

  • Pingback: Timbah Rooftop Heb Garden: Part 2 “Set up the cycles” « Urban GreenSpace

  • October 9, 2011 at 11:31 pm

    Thank you to all those you provided enlightened (and interesting) comments on the BSF. I recently added several kilos of high protein dried dog biscuits/feed to the rotating bin as our pet dog had died and the biscuits had become out-of-date. So, much like one (several?) of your readers when I opened my rotating bin yesterday I thought I had a problem when I saw the larvae. Having pondered a number of ‘solutions’ (quicklime?) I resorted to the internet and was relieved to find out that far from having a waste-management problem I had a solution. Thank you.

  • October 27, 2011 at 7:04 pm

    I believe the myth about black soldier fly larva may have occured due to a confusion with the Wax Worm. The larva from the wax worm, a grub-like larva, make their living within the beehive and consume honey. They metamorphisize into a moth.

  • October 28, 2011 at 6:26 pm

    BSF certainly aren’t pests in honey bee hives… I’m a beekeeper and recently collected a nest of bees that had set themselves up in somebody’s BSF box! Who’s pestering who? 😛

  • November 4, 2011 at 9:18 am

    hi i wanna bred this fly at home is there a way to breed this fly at home in a small space ?

  • November 9, 2011 at 1:34 pm

    oscar we have a topic about small scale systems in the forums (link). There are examples of a few systems there.

  • November 27, 2011 at 7:47 pm

    I tried the link, doesn’t work. I have a small starter group of a few thousand in a 1-gallon bucket, got them over a month ago while in Florida from a fellow BSF’er. I water the bread (food) every week, and check on them once every day or 2 to give them air. This spring most should be fully grown pupae, and I plan to buy a cheap tent to keep them once they “harvest” themselves. I’ll have a biopod with the ramp leading to a tray of soft dirt. Once they emerge as adults, the tent should (hopefully) give them a large enough place to breed. Strips of corrugated cardboard will (hopefully) hive the females suitable places to lay eggs. The tent will need to be in the sun. This is my first attempt, so we will see.

  • January 8, 2013 at 5:36 pm


    Successful Artificial Breeding !! To Carol and Jerry, regarding breeding of BSF within an artificial environment. I have just completed and confirmed a full life cycle breeding through the months of December and January of 2012/2013 in my basement. At present I will not be releasing the details as I hope to continue the research and further improvements but here is what I can share.

    The breeding cycle (including actual flight mating, egg laying and larvae grow-out bin) are all done within a 40 cubic foot enclosure located in my basement. Only artificial light is being used. Specific humidity and temperature are kept. A customized home-built larvae grow-out bin is being used. Five cardboard pads are being used for egg laying. Appx 1500 larvae were purchased to begin the process in late November 2012. As of late December 2012, the first mating was noted. As of the beginning of January 2013 the 1st signs of egg clusters appeared. As of January 8th 2013, I confirmed a very healthy population of BSF larvae that exceeds the original ‘start’ population. The BSF larvae are being feed a simple diet of table scraps. More coming at a later date.

  • January 8, 2013 at 6:10 pm

    One last note, there is snow outside while this breeding experiment is going.

Comments are closed.