I think I spent over six hours shooting video to capture this five second long event. I’m not really sure what value it has other than general coolness. :)

After exiting the pupa it ran to the outside of the bowl and spent about 10 minutes inflating it’s wings. Soon I hope to record that process and speed the video up.

hermetia illucens, black soldier flies, larvae, composting

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30 thoughts on “black soldier fly emerging from it’s pupa

  • July 8, 2008 at 5:05 am

    Still pretty cool :) If anyone else is watching, look at the pupae towards the bottom right-hand corner! They’re surprisingly fast!

  • July 8, 2008 at 10:48 am

    Wow, that’s super! I was expecting a time lapse video (since everything that I’ve seen emerge from a cocoon or pupa takes a while).

    I was surprised to see the little fly exit the pupa and get outa dodge so quickly. I guess if you’ve got only a few days to live, and in that time you need to find a boyfriend, mate, and lay eggs then there’s no time to dilly dally. Great video!

  • July 8, 2008 at 11:18 am

    As soon as the new BSF got to a “safer” spot it paused for about 10 minutes to inflate it’s wings before flying away. :)

  • July 11, 2008 at 3:25 pm

    @Nifty-Chicken: I know what you mean! I thought it would be one of those time-lapse videos as well, but the sounds of the birds chirping made me realise it wasn’t!

  • October 19, 2008 at 11:35 pm

    I have become fascinated by the BSF larvae that appeared in my worm bin. They can eat everything! I have a few pet chickens and they adore/willkillfor the larvae and so I decided to separate the BSFs from the worms—not an easy task—so that I could harvest them a little better. I have the BSFs in a 5 gallon bucket for now (the bio thing is on my Christmas wish list) and I am feeling sort of stupid about something. I rarely see the BSF flying around and I have never had them fly out of the worm bin or the bucket and yet I constantly have a new crop of larvae. I assume they are somehow managing to hatch, mate and lay eggs in the container and die without me ever noticing? The worm bin is a Can-o-Worms and the bucket has a decent lid.

  • October 20, 2008 at 8:52 am

    Hi Marilyn, congratulations on your BSF colony!

    I’m pretty sure that the BSF life cycle is not occurring within your containers. Most likely you’re having BSF females lay eggs on the outside of your bin. When the larvae hatch they are very tiny and can enter the bin through any small opening.

    Here’s a photo of an egg and the larvae are of course that size or smaller at first:

    bsf egg

    If you keep the larvae contained long enough you will probably see adult flies emerge from the containers.

    I’m not surprised you rarely see the adults because I’ve released 10’s of thousands of larvae on my property and sightings of adults is still relatively rare. The males don’t come around people or garbage, they’re only interested in mating. The females mate, find a food source, lay their eggs and then leave. You have to make an effort to see them coming to your bins.

    This post might be helpful:

    Thanks and good luck.

  • January 29, 2009 at 1:42 am

    I want to more about BSF. Thanks You.

  • January 30, 2009 at 10:11 am

    Hi Kunlachat,

    I hope to start some new experiments in the spring. :)

  • January 30, 2009 at 1:59 pm

    I would like to have a functioning BSF colony to process the my kitchen scraps and the entrails from backyard meat rabbits.

    Here’s the problem: I live in Eastern Oregon where the winters are quite cold. We can get down as low as 0 degrees F in the winter.

    1. Can I raise BSF’s in the summer and then somehow overwinter enough larvae to start a new colony the following spring?

    2. Does the BioPod have a entrance for the adults to come in and lay eggs?

    3. I have a basement that rarely falls below 40 degrees. Would that be useful in any way?

    Thanks for your help. I would really love to be able to grow and use these critters.

  • January 30, 2009 at 8:00 pm

    Hi Sue,

    With a little extra effort you can maintain a colony through the winter. The BSF will survive and process food as long as they are fed regularly and insulated sufficiently for the conditions. The temperature in your basement would make winter composting simpler. You could expect a few escapees, which wouln’t bother me, but might be an issue for some people.

    Yes, the BioPod has vents that allow heat to escape and female BSF to enter for egg laying.

  • January 30, 2009 at 9:39 pm

    thanks for the info Jerry.
    If you keep the colony going by insulating and feeding won’t the larvae reach maturity eventually during the winter? We’re talking cold temps from Oct to April or May. Can I refrigerate the ones that mature and keep them to start the new colony the following spring? If so, how long can they withstand refrigeration?

  • January 31, 2009 at 9:27 am


    You may have some number of larvae that mature, but the process is much slower in the winter. BSF mating stopped in my area almost four months ago, and only a small percentage of my colony has matured. Normally the larvae I’ve had for four months now would have matured in about 3 – 4 weeks. With enough insulation and food the larve could survive very cold temps, but it would require regular attention. I’m in warm southern Georgia and most of the time I can get be with very little insulation. On rare occassions it gets down into the teens though, and when that happens I’ve been covering the BioPod with a large garbage bag and I put an incondescent light under it. WARNING: I first put a 150 watt halogen light and I melted the plastic jar that collects the liquid from the unit. Also, it’s best to find a solution that doesn’t require electricity, especially if your goal is to be as Green as possible.

    I’ve been told that you can hold the larvae in a refrigerator, but it takes some effort because that enviroment tends to be too dry and the larvae need to breath. The basement you mentioned probably has more potential than a refrigerator.

  • January 31, 2009 at 12:36 pm

    I appreciate all your help, Jerry.
    In one conversation on your blog I saw a reference to putting an insulating disk on top of the colony inside the biopod. What do you recommend making this disk out of that would be okay for the colony? Do you think it would be enough to just insulate the top like that or would the whole unit require insulating in my 40 degree basement?

    How strong is the odor from the unit?

    How much do the larvae consume in the cooler months compared to the summer months?

    Once the unit is back outside in the spring/summer can I be reasonably sure that the flies will mate and lay more eggs in my climate? I’m pretty sure they are not native here.

    thanks again for all the help. I’m hoping the biopod can really work for me. Since it’s a pretty big investment I want to get as much info before hand as possible.

  • February 5, 2009 at 10:09 am


    I haven’t experimented much with an insulating disc for BioPods yet. Believe it or not I’m currently using a Tupperware cookie container filled with insulation. I live in Georgia only about 10 miles from Florida so insulation isn’t a huge issue for me. Any insulating material can be used, but it should be something the larvae can’t break up. Styrofoam works very well except that the larvae will dig into it eventually destroying it. Covering Styrofoam with a thin coating of fiberglass seems like it would be ideal.

    “Do you think it would be enough to just insulate the top like that or would the whole unit require insulating in my 40 degree basement?”

    I think an insulating disc would be sufficient if the larvae were fed regularly. Food is the fuel that generates the heat in the first place. If the colony goes more than a few days without a feeding the temperature will drop and the colony will begin to go dormant.

    “How strong is the odor from the unit?”

    The odor of a BSF colony is very mild and not offensive, assuming the colony is in balance. Once a colony is established it’s very easy to keep it in balance and in fact the only time I had problems was from an extreme test involving pond fish that had been dead for several days. Don’t try that at home! :) Here’s a link to my post about that experience:

    “How much do the larvae consume in the cooler months compared to the summer months?”

    The rate of consumption will be related to the temperature of the colony. The more food (fuel) you add the higher the temperature of the colony. The higher the temperature of the colony the more food they can process. I think momentum is the key in cold weather. Dr. Olivier, the inventor of the BioPod, has stated that the larvae can even consume more scraps in cold conditions because they are less prone to overheating than in summer weather.

    “Once the unit is back outside in the spring/summer can I be reasonably sure that the flies will mate and lay more eggs in my climate? I’m pretty sure they are not native here.”

    Yes. I believe the primary reasons BSF would not be found in a given area are low humidity first, and extended periods of cold weather second. A BioPod or similar device compensates for the these influences by protecting the colony. High humidity is vital to the larvae and the regular addition of food scraps supplies it. The part of the cycle that happens outside of the unit (pupation and mating) don’t seem to be as dependent on high humidity. We already addressed cold conditions and you always have the option of restarting a colony in the spring if you don’t want to maintain one through the winter.

    I hope that helps, please let me know if you have more questions.

  • September 6, 2009 at 11:35 pm

    1. Can you please tell me if bsf larvae turn into flies even if they cannot leave the bsf bin. I have a colony in a plastic cowfeed container and have no provided ramps so the ones about to pupate can escape and burrow in the ground.

    2. Since I assume females are not laying eggs during the winter, is a colony able to overwinter because the growth of larvae is retarded by the cold?

    Really appreciate any comments on these questions.

    • September 7, 2009 at 9:55 am


      1. The bin doesn’t represent an idea pupation site but I think many or even most of the pupae should survive to emerge as adults. I haven’t tested that so I can’t say with any authority what percentage will make it.

      2. Yes. The larvae will remain in the juvenile stage and continue to eat until the weather begins to warm. Last winter I had larvae that spent 5 months in the juvenile stage until spring.

      You’re welcome!

  • September 7, 2009 at 8:17 pm

    Thanks, Jerry, for your help. On another issue, please tell me what is happening here. It seemed my colony was slowing in activity. With a shovel, I dug down 4 or 5 inches deep. It was quite damp and in the muck were a lot of totally inert larvae…actually they looked dead. I picked out about 10 of the biggest ones, plopped them in a shallow pan, and left them in my carport. After some time they began to move. I gave them a couple of ounces of damp coffee grounds and the next day they were actively crawling around the pan and they had swollen up to about double the size they were when I put them in.

    Why did they look dead in the bin? Am I not feeding enough…or is it too damp because I’m feeding too much? I don’t know what’s going on.

    • September 8, 2009 at 8:31 am

      Jim, it sounds like temperature was the main factor in what you described. BSF larvae will slow down in proportion to the decrease in temperature of their environment. I think that when you moved a few to your carport they simply warmed up and resumed activity. As the nights are progressively becoming cooler you’ll see the BSF tend to slow down, but there are steps you can take to counter that trend.

      The temp of the outside air isn’t the primary issue because the larvae generate heat as they metabolize food. If there is something insulating the larvae then the temp of the colony can be significantly higher than ambient temps. In a compost heap, or a specialized BSF unit, the accumulated compost serves as insulation and by covering the colony with additional insulation you can keep the larvae active in cold weather. I have and old post that touches on this and I’ll be involved in keeping my colony active through this winter. Here’s that old post:

      Insulation will help contain the generated heat, but food is needed to “fuel” the activity of the BSF. I’ll guess that when you found the sluggish BSF there wasn’t a significant amount of ready-to-eat material available to them (foods soft by nature or from decomposition). I think that if you had added fresh waste to the colony on the previous day that when you dug down you would have found a concentration of actively feeding larvae. A BSF unit is a biological engine and without a steady supply of fuel (food waste) it will stall.

      Dampness isn’t an issue for BSF larvae as long as they aren’t drowning in built up liquids. Even with liquid in the bottom of a container the BSF will be fine if there is material above the liquid level. The main problem with accumulated liquids is that the larvae can’t effectively process waste that is submerged. The constant churning action of a BSF colony is what keeps a waste pile aerated (aerobic) which is why odors are minimal and sometimes even pleasant in a properly balanced colony. Waste that is submerged is deprived of air (anaerobic) which leads to growth of problematic anaerobic bacteria which cause foul odors.

  • September 8, 2009 at 8:57 pm

    Thank you, Jerry. I am going with your second possibility — that perhaps the bsf grubs had slowed down from lack of abundant food. The bin is in the sun and covered with a sheet of corrugated tin positioned about a foot above the container…so I think the ones I put in the pan actually cooled off a bit by coming into the carport. Of course this raises another question…were they too hot in the bin? Duh. This is Mississippi…perhaps the heat causes dormancy.

    Okay…a question about your video above. I noticed none of the larvae are moving. So…when these flies are about to hatch from the pupa, are they immobile? Thanks again.

    • September 9, 2009 at 9:56 am

      The bin is in the sun and covered with a sheet of corrugated tin positioned about a foot above the container…so I think the ones I put in the pan actually cooled off a bit by coming into the carport.

      Jim, not to be argumentative, but I still think temperature was the main reason for the sluggish behavior of your BSF. I live 30 miles north of Tallahassee, FL and I’ve recently been observing the same behavior you described. I checked the recent weather in MS and found that the evening lows have been in the mid sixties. Under those circumstances your bin could certainly cool down to below 70º and at that temperature BSF larvae will slow down significantly. The shade that you have over the bin would allow it to remain cool well into the day. Of course the air will warm much more quickly than compost so that might explain why the BSF you moved to the carport could have been warming up. You can easily test this theory with an inexpensive meat thermometer inserted into the compost. Cool temperatures and a lack of food (fuel) would result in semi-dormancy.

      Last week I saw firsthand what happens to BSF grubs as the temperature gradually increases. I removed about a cup of grubs from my BioPod to use as bait to harvest fish from my pond. I had them in a black plastic container and the temperature was in the mid 80’s. Since BSF larvae can survive up to 116º I didn’t believe they were at risk of overheating. I returned to the container every few minutes and I noticed that the activity level of the grubs was increasing gradually as they warmed up. I didn’t realize it but the temperature in the black container was approaching the upper limit that BSF can tolerate and a one point I returned and found that every grub had died. I had observed a very high level of activity just a few minutes before finding the dead grubs. They still provided the service of nourishing my pond fish, but in the process I learned that more heat equals more activity, right up until the point where the limit is reached.

      About the video; what you see there are not larvae, they’re pupae. They look just like the final stage larvae but they are relatively stiff and they don’t crawl even when disturbed. After the mature larvae pupate it takes two weeks or more for them to transform into adults depending on the ambient temperature.

  • September 9, 2009 at 11:22 pm

    Thank you, Jerry. I see what you mean about the temperature. I was assuming the temp in the bin was way over what it apparently was.

    Thanks for the larvae-pupae difference. I am really hurting for vocabulary as I am new in the bsf world.

    A question about practical use. I am maintaining these bugs out of fascination. Secondarily they are probably doing something for the soil in my cow feed container. I do some container growing in the summer. I also do not fish or have any fish or chickens.

    So here is a strange question. I read that the larvae are about 60% protein, 40 % fat and bacteriostatic. Do you know of any instances in the world of human consumption? I am not personally ready to eat bugs, but have thought about it…well, hypothetically. :) I have an interest in wild edible plants, etc. I had a student from Liberia who told me she ate a species of termite there.

    For me, what do you think the practical potential for these larvae would be? Many thanks.

    • September 10, 2009 at 9:26 am

      You’re welcome Jim,

      It’s very possible I’m wrong about your case, but that’s the best assessment I can make from a distance. I would be interested in a temperature reading if you’re inclined to take a measurement.

      For the record; the nutritional data I’ve seen on BSF puts the protein/fat at 42/35% for dried larvae and 17/9% for fresh larvae. Insects and insect larvae are consumed on a daily basis around the world, and an objective person wouldn’t have an issue eating them. It’s true that BSF larvae are scavengers but so are shrimp, lobsters, and some of the fish we eat. If you’ve ever eaten “peel and eat” shrimp you’ve eaten a scavenger, and probably also the contents of it’s digestive tract (shrimp poo). Our bodies can easily process items that our minds cannot. It’s difficult to imagine eating a larva that was raised on a diet of manure, but what if it had been raised on fresh grains or fruit and under sanitary conditions? In that case the only issue left would be cultural. If you raised BSF on pineapple and then dipped them in chocolate I think you’d have real crowd pleaser (if they didn’t know what they were eating). :)

  • September 10, 2009 at 10:29 pm

    Thank you, Jerry. I am presently too much of a chicken, but if you ever get “objective” enough to sprinkle a few of these critters on your cereal, please let me know how it turns out! :)

    I guess my main use for them is the improvement of container soil. But do you think that vermiculture is best for that…as worms leave more soil amendment in terms of volume?

    Another issue… my bin is in the sun. Can I take the galvanized metal from over the container and let sun and rain hit it? I have the original top for this cow feed container also and can use that if necessary. I was afraid the larvae would get too hot if I put this top on. This particular container is too heavy for me to move into the shade. How should I maintain it as far as coverings are concerned?

  • November 1, 2009 at 10:40 pm

    Jerry, is anybody home?

  • January 27, 2010 at 11:52 pm

    I’m try to study about BSF in Thailand but now I have problem with them. This problem are the BSF not matting and laid, I used nylon cage 30x45x20 cm and pineapple peel 1 kg for rearing 5 pairs of them but not laying eggs .could you can show how to make them laid eggs , Thank you very much.Oh,and I study BSF in seasonal distribution,rearing by fruit peel and nutritional value from them. Thank you again.

    • February 6, 2010 at 9:22 pm

      Hello Kunlachat,

      BSF mate while in flight and the space you are providing them is not large enough. I have read that the space should be a minimum of 3m X 3m. It is also best if they have much natural sunlight and also to keep the environment warm.

      Optimum for Mating: “Adults typically mated and oviposited at temperatures of 24 C (75.2 F) up to 40 C (104 F) or more. Booth and Sheppard (1984) reported that 99.6% of oviposition in the field occurred at 27.5 C to 37.5 C (81.5 F to 99.5 f)” (10).

      (The information above was found at BioSystem Design)

      I have never raised BSF in any type of enclosure. I live in a place with an indigenous BSF population and I’m happy to let mating occur naturally in the wild.

      Good luck!

  • February 4, 2010 at 12:54 pm

    Hi Jim,

    I didn’t mean to ignore your question from so long ago, I thought I had typed a reply but I guess I didn’t…

    “I guess my main use for them is the improvement of container soil. But do you think that vermiculture is best for that…as worms leave more soil amendment in terms of volume?”

    Short answer; yes, worms are best for producing large amounts of soil amendment. BSF shine in their usefulness to drastically reduced the volume of waste and as a high quality feed for animals (and in theory, people :) )

    “Another issue… my bin is in the sun. Can I take the galvanized metal from over the container and let sun and rain hit it?”

    In terms of temperatures, you can do anything as long as the colony remains in a safe range. In some northern areas I’m suggesting that people keep their units in the sun because of overall cool conditions. A good example of this is Seattle and Vancouver. In the summer in the southern US it would probably cause the BSF to crawl away. BSF can survive up to 115º F (46 C) so it’s best to aim for 100º (38 C) or lower.

    “This particular container is too heavy for me to move into the shade. How should I maintain it as far as coverings are concerned?”

    It’s hard for me to say and I think you might need to experiment. Each container and situation is unique. Rain itself won’t harm the colony, but you must have good drainage in any BSF colony. One factor with rain/humidity is that BSF can scale a vertical surface if condensation is present. Part of maintaining a dense colony is containing the larvae and if your unit allows them to easily escape you will not reach a very and consistent efficiency level.

  • April 25, 2010 at 3:49 pm

    We have been using BSF for fish bait here in the Philippines for decades without knowing its name or where it come from.What we observed is that BSF loves coconut meat and free range chickens loves to scratch the ground and eat the larvae.

    • April 25, 2010 at 7:17 pm

      Hi nopi,

      The same is true in the southeastern US where I live, except for the coconuts. Here it is more about corn, but the idea is the same. :)

  • September 27, 2010 at 9:55 pm

    Thank you, Jerry. I realized, of course, the delay was an oversight, so no problem. Just good to get the information. I have a healthy colony this summer and have had a lot of females laying eggs. Fun and interesting to see them.

    By the way, do you know of any humans eating the larvae…anywhere in the world, that is? People eat everything else. Someone’s got to be eating this, too! :)
    Thanks again.

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