Aquaponics and Black Soldier Fly Larva
Black Soldier Fly (credit to Dave's Garden)
Black Soldier Fly larvae (BSF) are the juvenile grub of the BSF, and fish and chickens find them DELICIOUS. While the notion of cultivating fly larva (uh, don’t you mean maggots?) seems pretty nuts, ends up BSF are very different than your ordinary housefly. First, they don’t carry diseases, they cannot bite or sting, and, the experts claim, they won’t annoy you at picnics. They are
voracious eaters of compost scraps (including pet waste), eliminating most food scraps in 24 – 36 hours.
Some very fun guys at a company called ProtaCulture have developed a product that has been specifically designed to attract, grow and harvest BSF and their yummy young. It is called the BioPod Plus, was over 8 years in development on 3 different continents, and can process up to 5 pounds of kitchen waste and pet feces a day! Here is a video clip of our friend Murray Hallam from his Aquaponics Made Easy video describing how he uses the BioPod to grow food for his fish.
Last fall when I was starting to think through a product line for The Aquaponic Source, I had a fascinating email exchange with Karl, one of the founders at ProtaCulture. At one point I asked him about the difference between using red worms for composting and BSF larva. After assuring me that he has nothing personally against red worms, here was his response:
- Red wigglers are not efficient for processing meats, dairy products, oily foods or grains. Black soldier fly larvae readily consume all of these food types. Worms also don’t process citrus, and large food needs to be chopped. BSFL do process citrus and chopping isn’t necessary.
- With worms it’s recommended that you bury the food scraps to avoid odor and pest problems. With BSFL the scraps can be put on top of the pile because they don’t last long enough to spoil and smell bad. BSFL give off an info-chemical that repels other flies and it’s relatively rare to see another species in the container.
- Worms require periodic harvesting because their castings are toxic to them, and this has to be done manually. BSFL will self harvest when they are mature. In their last stage as larvae their mouth is replaced by an appendage that helps them crawl out of the container. They empty their gut and excrete an antibiotic in preparation for pupation. The container has been designed so that the prepupal larvae drop into a bucket when they exit the container, and they can live in the collection bucket for
Black Soldier Fly Larva (credit Black Soldier Fly Blog.com)
several days, maybe even weeks before being collected. At this stage they don’t eat. From here, it is a simple matter to collect them and feed them to your fish.
- Worms require a fairly specific environment with regards to moisture, ph, and temperature. Different sources recommend keeping worms at a minimum of 54 and up to 70-84 degrees depending on the source of the information. BSFL are much more tolerant. Once a BSFL was tested by being submerged in isopropyl alcohol for two hours and it survived. They can survive between just above freezing and about 100 degrees.
- Worms process about three times their weight in food scraps per week. I assume five pounds of worms would be a substantial quantity and would consume 15 pounds of food per week. A BSFL colony in a 2 foot diameter container can process 11 pounds of food every day. Even with 10 pounds of worms you would still be limited to 30 pounds of scraps per week.
- Most kitchen scraps are converted into BSFL at a rate of 5 to 1 so 10 pounds of food scraps would yield about 2 pounds of larvae, i.e. delicious fish food, per day.
Sure convinced me, but tragically we don’t have BSF in Colorado! Ends up you need to be in zones 7 – 10 (sometimes 6) to have BSF, and because they are winged creatures having a native supply is a requirement. So there is a plus for the redworms – they won’t fly off on you!
The BioPod Plus
For more information please check out The BioPod Plus at The Aquaponic Source. If you purchase one before June 15th we will pay the shipping.
Happy grubbing!
Aquaponic Gardening Blog 
Do you know of any sources to get a starter population of BSF larva to help kick start the BIO pod?
Hi Aleece,
The guys that make the BioPod have done a great job with their user guide, and hopefully they won’t mind me quoting from it…
Acquisition of BSF. If you have a native colonies of BSF in your area, chances are they
will populate your unit without active intervention. This even happens on patios of
multi-story complexes in highly urbanized areas. Adult females are attracted to
imperceptibly low levels of food odors emitted from your pod and will
instinctively oviposit (lay) eggs under the protective, convenience cap covering
the top ventilation port. The subtle scent of food scraps also serves as a directional
guide to newly hatched larvae. Once a female finds your pod and lays eggs, it usually
takes about 1-2 weeks before you notice the juveniles actively digesting the contents.
If you want to accelerate the formation of your colony, or you reside in an area where few to no
BSF are present, you may inoculate your unit with an egg case or juveniles from an existing pod,
compost pile or worm bin. Adult BSF are relatively slow flyers and are easy to capture from an
existing compost pile or worm bin (that has food scraps), due to their docility while at rest.
Simply net a few adults and place the in the pod, and the females will do the rest. You may also
obtain live juveniles or dormant puparium (ready to hatch into adults) from online sources.
Whatever the method used to artificially introduce soldier grubs into your system, the results will
be the same – quick maturation, and if weather permits, pupation into a breeding population of
adults – ready to continue the lifecycle by laying new eggs in your pod. Keep in mind the liquid
tea mentioned previously is a strong attractant – a small quantity from another pod added to your
pile will draw in any gravid females from the surrounding vicinity, and stimulate them to lay eggs.
Another simple way of establishing a colony fast is to take some of
the egg laying strips from an active unit and place them using Velcro
on the inside of either lid. Such an exchange will not harm the
existing colony or eggs. Fresh clusters of BSF eggs are bright white
in color, whereas empty casings are brownish. Once a year, clean
out and refresh your plastic corrugated poly egg strips with a quick
rinse of mild soap and water. If made from cardboard, simply
discard into your compost pile and cut new ones from an old box.
Order some Phoenix worms (aka BSF Grubs) and let them mature into adults.
There’s a way to make something inexpensively, if someone wants another option, instead of purchasing a “biopod”. It can be made with two garbage cans one smaller, inside the other, think the inside one is lifted up on something like a block and there are holes drilled in..and a hole to the outside that I think the flys go in and out of. I have to look up my notes and get the details. I think it was called a “bio reactor” and it would allow for scraps to be compost fast and is made for breeding BSF.
OK, this is an awesome idea. I have a worm bin and I’m familiar with the downsides of it. But what is to prevent the other flies … bluebottles in our area … from making the bin into THEIR breeding ground? The only way I can see this working is if it’s closed to keep the rest of the insects OUT, but the unit is specifically designed to let local bugs IN. Our worm bin is closed for that reason.
Interesting question, Heather. Here is the response from Karl at ProtaCulture “The BSF produce signature pheromones and other natural chemicals that repel other fly species. You may see an occasional fruit fly or house fly, but that is really only the case with the initial start up – once the BSF take over – that is really all you find – BSF. Unfortunately, that is not the case with redworm bins. One recommendation for WORM bins (not BSF bins so much because it is not relevant) is the have a 1″ topper of shredded long cut, moistened paper to cover all of the worm bin contents – flies don’t normally lay their eggs on paper, only food scraps – so if you cover them, you mitigate flies.”