refreshing the colony

restarting the colony 2009

Starting my third year with the black soldier fly

I’m going into this season with a small colony made up of grubs that were laid last fall. Where I live the winters are mild so it was fairly easy to maintain the colony through the cool months. At the end of last summer my BioPod was full of compost and I should have harvested it.  As a result of that neglect my beautiful compost became anaerobic, dense and a bit smelly. What can I say? It’s been a hectic year. :) I think early fall may be a good time for removing the BSF compost because the grubs are likely to be less active on average in winter versus the warm months. I believe the churning action of an very active colony (summer) is an important factor in keeping the compost aerated and “fresh”. I said early fall for compost harvesting because I’m afraid that if you wait too long in the season you won’t have time to rebuild the colony to near maximum size in preparation for the winter when BSF breeding stops (unless you’re in the tropics).

Spring cleaning

first BSF of 2009

BSF don’t normally land on people,
but this one had just emerged from it’s pupa so I was able to handle it.

I removed all of the compost and washed my BioPod. I hand picked a few hundred of the light colored juvenile grubs from the old compost and added them to the unit along with some fresh food scraps. I didn’t clean the grubs themselves so a small amount of the old compost was transferred along with them. This old material will act as a great attractant to BSF adults who have now started the mating season. A healthy and balanced BSF colony doesn’t have a strong or bad odor, but the females will always be attracted to the faint scent of an established colony. As I mentioned previously, my compost is anaerobic now and therefore smelly, but the typical mild smelling compost from a balanced culture would work just as well.

BioPod-spring cleaning

A new drain

As you can see from the first photo in this post I have replaced the BioPod’s liquid collection jar with a straight drain into the ground. (I hope you won’t be too disappointed with me Dr. Olivier.) I haven’t been gardening and to date I haven’t done anything productive with the liquid (also called “tea”). For that reason I’m opting for the convenience of the straight drain for now. To see how I set up the drain you can go to my “Tips and Tweaks” page.

The pond

You can also see my pond in the photo. I moved the BioPod near the pond because I’ll be feeding fish scraps and culls to my BSF colony this year. I don’t enjoy killing fish, but to maintain the population in a healthy balance I will be removing some of them. I’ll have some help from birds, turtles, and snakes, but the pond is fairly close to the house and wild predators are limited. With the BioPod I’ll be able to convert the excess fish into nutritious black soldier fly grubs and return them to the pond as fish feed. I have a post about my philosophy regarding feeding BSF grubs to other animals here.

Black soldier fly grubs are also fantastic fish bait, so having the BioPod near the pond will be very convenient for fishing. I’ve created a page about BSF as bait which you can find here.

Winter BSF culturing

As I mentioned earlier I did keep the colony going through the winter, but I didn’t keep any records. The one thing I can confirm is that the BSF grubs will interrupt their usual development during the cold season. I had very few BSF laying eggs by October and the last one I observed laid her eggs late in that month. By November I stopped seeing any smaller grubs in my colony. I assume then, that the grubs that  currently make up my colony are at least five months old. During the summer this stage would only last 2-3 weeks. Next winter I want to be better prepared to test cold weather bio-composting and I hope that some of you will participate in it with me. At the end of this summer we should start a thread about this at the BioPod forum to share strategies and results.

Logging this year’s results

My goal this year is to keep a log of all the food I add to the colony and the weight of the grubs produced. I’ll be fairly general about recording the composition of the food scraps so this won’t be a controlled experiment. The fact that I’ll be adding a large amount of whole fish and fish scraps will certainly effect my results. My goal is to provide a general outline of what you might expect. You can find the log in the column on the right of this page under Black Soldier Fly Pages, or simply click here.

Appreciating Bug Guide.net

An interesting and informative site.

Visit BugGuide.net

bug-guide-about-page

Black solidier fly larvae-variation in growth rate

I recently collected a newly laid clutch of black soldier fly eggs for a photographic study of their development and I isolated three of them for the photos. I placed the three individuals and the remaining few hundred BSF from that clutch into identical containers. I didn’t keep detailed records, but there is an interesting comparison that I believe illustrates the flexibility of BSF development.

larval-growth-variance-w

Temperature and humidity were approximately the same for both batches of larvae. The large larvae is one of the three that was separated for the photos and all three are similar in size. The small larvae is from the more crowded container which held the bulk of the larvae. The same type of food was available to both groups, but I can’t attest to the quality of the food in the more crowded environment that produced the smaller larvae. From casual observation it appeared that there was always food available to both groups. The most obvious difference between the two containers was the density of larvae. The small larvae where moved into a larger container six days after hatching and seem to be healthy and growing, but are still relatively small.

I imagine any properly educated researcher would not be surprised by this difference in development, but to this layman it’s very interesting.

Mythbusting black soldier flies

bsf-magnifying-glass-b

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 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.

To be continued… larvae, biopod, composting, black soldier fly, flies, composter

Black soldier fly composting in the frigid north

frigid north

Black soldier flies are common in tropical and subtropical regions, but their range extends to the most northern states of the continental U.S. You can easily operate a BSF bio-composting unit in northern states during the warm months, but you can also maintain the colony through the colder months with a little extra effort.

A black soldier fly colony generates its own heat

Maintaining a BSF unit in cold weather is possible because the metabolic action of the larvae eating creates heat as a byproduct. Under cold conditions keeping the colony at the optimal temperature range of 85° - 100°F (30°-38°C) is as simple as consistently feeding them and placing an insulating material directly on top of the pile. Simply remove the insulating material, add the food scraps, and then replace it. It’s important to feed the colony consistently in cold weather because without food the temperature will drop and the colony will become dormant. If the larvae are exposed to freezing temperatures they will die. Also, any insulation on top of the colony needs to have an air gap between it and the BioPod.

Maintaining a BSF colony during extended periods of sub-freezing weather is possible, but it may be more than you wish to get involved with. In that case you can enjoy BSF culturing up to the point where the weather in your area makes it difficult and then resume in the spring.

Process more food scraps, harvest less larvae

In cold weather the time it takes BSF larvae to mature increases from the usual few weeks to a period of up to several months. The colony has little or no crawl-off of mature larvae and that enables you to continue bio-composting without the need to replenish the larvae via visiting females.

In warm weather the colony has a tendency to overheat, so in cool weather the larvae are able to consume even more food scraps.

How adventurous are you?

I don’t recommend bringing the BSF unit into your living room, but why not try keeping it in the garage or a shed when the temperature drops? Sure, a few larvae might get out, but so what? The adult fly will just emerge from it’s pupae in the spring and then you’ll have the pleasure of gently capturing it and releasing it outdoors. They are harmless creatures after all. I don’t think a heated space would be the best choice though, because it might trick the larvae into developing too quickly. I would guess that 40° - 60°F (5°-15°C) is a good range to try testing this theory, and of course you would need an insulating disc of some sort to keep the colony warm. The degree of insulation would depend on the ambient temperature in the space.

I’m cursed with living in an area that rarely gets cold so if you try this experiment please let me know how it goes. I would love to post photos of your set up (if it works :) ).

Mike made a comment below reminding me of a presentation by ESR about BSF culturing in winter. Here is a link to that article: http://www.esrla.com/winter/frame.htm

Black Soldier Fly cultivation - “nuts and bolts”

nuts and bolts 4

The purpose of this post is to feature a blog that is valuable to anyone researching black soldier flies. It’s called BioSystems Design and below is an excerpt from their “about” page.

About BioSystems Design.

BioSystems Design LLC. is dedicated to the transformation of what was previously considered waste into valuable products.  Our institutional knowledge and designs are based on nature, as nature is the premier designer of BioSystems that use waste as production inputs.

A US company founded by Grant Canary in Portland, Oregon, our studies of nature and biosystems are conducted in Bogotá, Colombia, at our two research laboratories, with our prestigious partner organizations, La Universidad Nacional de Colombia and La Universidad de La Salle.

BioSystems Design LLC.  maintains close partnerships with ESR International and Otterwasser Gmbh.   Our commitment to ESR International is the design, construction, and operation of an industrial production process that feeds crop and food waste to larvae, harvests that larvae, cooks it, pulverizes it, and sells the high protein larvae-meal to animal feed producers.

Our commitment to the German wastewater consultancy, Otterwasser Gmbh, is to sell, build, and operate their innovative energy generation and wastewater treatment systems in the United States.

From the BioSystems Design blog:

A Primer on Black Soldier Fly

The following represents the “nuts and bolts” facts relevant to Black Soldier Fly cultivation which were found buried inside of research texts. The key distinguishing factor is that they are organized by environmental considerations (in bold). Where inconsistencies are found they are noted. Assistance, suggestions, along the lines of additional sources, inconsistencies, and added environmental considerations are highly welcome. I hope to make this a very active post.

Take 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.  BSF aren’t magic but it’s hard to imagine a much more efficient solution to a growing problem.

adult bsf

Bio-conversion

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 or paper.
  • Larvae reduce the volume of household food waste by up to 95%.
  • A 2 foot (60cm) container of larvae can process several pounds 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.
  • BSF grubs can be processed to create bio-fuels and other valuable products

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?

b

Collecting the immature larvae

This method doesn’t involve the dark, prepupal larvae which are self-harvesting

The coffee colored BSF larvae (prepupae) are the final stage before pupation into adult BSF. To our advantage they are programmed by nature to crawl away from the food source in search of a suitable pupation site. In a properly designed BSF unit these larvae crawl up a ramp and drop into a collection bucket where they will live for weeks without any maintenance.

The method described below is for harvesting the earlier stages when the larvae are actively feeding and growing. It doesn’t work for the mature larvae because they don’t eat therefore aren’t attracted to the bait in the collection container. It works very well for the light colored immature larvae.

The Immature Larvae Collection Device or ILCD (old butter tub)

Take a cheap container and cut some small holes around the bottom edge.

immature larvae collector with fish pellets

(click on images to enlarge)

Add something delicious (any food scraps will do), and simply place it on the surface of the compost. I used moistened fish food because I’m training my fish to eat it and this is a good way to introduce them to the flavor (I feed the larvae to the fish). Just about anything will work, but fresher items will make handling the collected larvae more pleasant.

The photo below was taken 2 minutes after placing the tub on top of the compost.

immature larvae collector after 2 min

This is after 11 minutes.

immature larvae collector after 11 min

The photo below was taken 40 minutes after adding the container.

immature larvae collector after 40 min

This quick harvest totaled about 2 cups (.5 litre) of small to medium larvae. I don’t have many large larvae at this time due to the crash I caused in the colony a few weeks back. I do have a lot of larvae, just not large ones yet.

fishing, bait,

Feeding black soldier fly larvae to Redear Sunfish

redear sunfish preparing for supper

I’ve been feeding BSF larvae to my redear sunfish (shellcrackers) everyday for about a week and they are taking them with enthusiasm. They have a preference for the immature larvae over the dark prepupal larvae, but they still eat the dark ones pretty well. I think the prepupal larvae might be more foreign to them than the light colored larvae, but I think with some conditioning they will eventually accept  them just as well. There are some individual fish that already take the prepupae well which is why I suspect it isn’t a taste issue or something like that.

(Wow. That video quality is terrible. I’m open to suggestions if anyone would like to offer some advice about uploading video. I’ll leave this up for now, but I have to do something! I tried blip.tv and PhotoBucket which were better quality, but the embedded players for these sites ruined the xhtml validation for my blog, the YouTube videos don’t.)

Here’s a link to a better quality version of the same video at Blip.tv - VIDEO

Update - August 14

These fish are in a pond that was built in January 2008 and I only stocked 24 adult redears. (I also stocked 110 very small redears in late March and you can see a few of them feeding with the larger fish in the video) At first when I began feeding them BSF larvae the fish were concentrated in one area of the pond because they were on spawning beds. This made it very convenient to hand feed them, but I assumed they would disperse once the spawning season passed. Well, the spawning seems to be over and they’re still concentrated in the same spot, and I’m pretty sure it has something to do with the daily offerings of black soldier fly larvae. Lately when I walk up to the feeding area I see the fish lining up just off the bank of the pond about one meter from the water’s edge. All fish are oriented on me as they wait for the rain of tender BSF morsels. They will swim into water that is only a few inches deep to snatch up the larvae. Previously I was unaware of the popularity of fly larvae as fish bait, but now I can understand why they are so effective.

If you’re a sensative person you may hesitate at the idea of sacrificing the larvae to fish this way but there is another way to look at it. In nature fly larvae have a high mortality rate and the balance of the population is based on the vast majority of them not surviving to reproduce. Two BSF can produce between 500 and 900 eggs depending on which report you read, and to maintain the normal population only 2 of those several hundred will survive to lay more eggs. I address this issue in more detail here: Feeding black soldier fly larvae to other animals

My new (ESR/ProtaCulture) BIOPOD™

My first BioPod

After working with and blogging about black soldier fly larvae for over a year I finally have one of the first BioPods. For the past year I’ve been getting by with my homemade unit and I’m looking forward to testing this product. With that previous experience I’m pretty familiar with the shortcomings of my unit and from what I can tell by looking, the BioPod addresses those problems.

I’m starting this colony from scratch

I already have a colony of BSF larvae established, but I want to take this opportunity to start a BioPod from scratch. On one hand it seems like I’ll have an advantage starting this new colony because I have an established BSF population on my property, but that may not be an advantage. My existing colony which is 200 feet (60 meters) from my new BioPod is a powerful attraction to any female BSF looking to lay their eggs. BSF larvae do not have a strong or unpleasant odor, but their scent is easily picked up by the adult females.

The bait

The BioPod user’s guide recommends starting your colony with normal household food scraps except for meat or fish. It’s not a problem to feed meats or fish to an established colony, but before that stage those items will attract too many unwanted critters. I started my first colony using assorted scraps, but for this unit I’m using only dry dog food. I added 2 cups (.5 liters) of it, slightly moistened. The humidity where I live is usually 50% or higher so I don’t think I’ll need to wet it further. The purpose of wetting it in the first place is to enhance the smell and it may not even be necessary. The reason I’m testing with the dog food is because some types of food scraps start to look nasty after a few weeks and the dog food is fairly stable. In the end it probably doesn’t make much difference, but it’s hard for me to follow instructions sometimes. :)

JULY 10

This is the day my BioPod arrived. I set it up in about 20 minutes, added the bait, and so far that’s all I’ve done. It’s important to deter ants from entering the BioPod so I’m going to treat the legs of the stand with a small amount of Bug Stop.

JULY 15

It’s been raining a lot lately and that seems to slow down the BSF adults. I haven’t observed any BSF or seen any eggs on the new BioPod yet. This morning when I checked it there were a few house flies on the lid and I could smell the dog food from outside. Inside there were a few fruit flies and nothing else.

JULY 20

Still no sign of black soldier flies in the BioPod, even though they’re active only a few hundred feet away.  I guess this reinforces the idea that if you maintain a BSF colony that you won’t have them all over your property. I’ve seen a few house flies on the BioPod lid but none inside. This may be because they aren’t willing to enter the small opening in the BioPod. My homemade unit had a fair amount of house flies entering it at this stage.

The dog food I used as an attractant is beginning to mold and I don’t think it was necessary to moisten it. Still not bad for 10 days in the summer though. :)

It can be frustrating waiting for the BSF to show up at your BioPod. I think the key is getting that first female  to lay her eggs in your BioPod. Once that happens I think the others will quickly follow.

JULY 24

Still no luck in the new BioPod and I may have a clue why it’s taking this long, even with the healthy BSF population on my property.

frog on the BioPod lid

I’m sure this one frog isn’t the only reason it’s taking a while and it may be the other colony I have on the property is getting all of the attention. Still, that is one well fed frog. :)

JULY 27

Okay, first of all, the frog was back! The frog from the photo has some unique markings and I believe the one I saw today was the same frog. The first time I moved it about 50 feet, this time I tried 100. :)

Other than that I want to say UEREKA! I now have BSF eggs in my new BioPod. I’m surprised how long it took, but as I mentioned earlier I believe my other colony was attracting most of the females.

It won’t be long now!

Black soldier fly eggs on egg disc

(egg disc removed from BioPod for photo)

AUGUST 1

I have a few different types of larvae feeding in the BioPod now which are too large to have come from the eggs in the photo above. I think I’ve seen one of these species in the past when starting a BSF colony, and I think it may be one of the other soldier fly variaties. Here’s a photo of that fly:

possible soldier fly - not bsf

(unidentified fly - not bsf)

There are over 200 members of the soldier fly family (Stratiomyidae) in North American, but I assume the other soldier flies won’t work well for bio-composting.

I’m fairly certain some of the larger larvae feeding in the BioPod are black soldier fly larvae, so it shouldn’t be long before they become the dominant species.

Frog removal is becoming a daily chore. :/

AUGUST 2

I may have been too conservative with the food scraps added to the Pod so far. I’ve limited the food source to the original few cups of dry dog food put in at the beginning. Since there are larvae now present I decided to add more food today. When I removed the BioPod lid I was happily surprised to see 4 female BSF laying eggs. If they all survive that could be a few thousand larvae.  Two of them kept laying will I poured the sloppy scraps in.

AUGUST 10

Today there were prepupae in the collection bucket. Prepupal larvae (prepupae) are simply the mature, dark colored larvae that are in the final stage before they pupate and change into adult black soldier flies. Although the light colored immature larvae sometimes migrate out of the BioPod the majority are these prepupal larvae.

prepupal black soldier fly larvae

Above: The BioPod collection bucket

The number of larvae actively feeding in my new pod is steadily increasing as is to be expected. I’m short on food scraps so I’ve been feeding this colony a type of hog feed that is made from cornmeal. Ideally I’ll find a source of food waste to use but for now I don’t have the time to find it or fetch it. : /

bsf colony on August 10, 2008

SEPTEMBER 24

I haven’t had much to report since the past several weeks have been business (BSF composting) as usual. I add scraps every 2 or 3 days and I occasionally empty the collection bucket and liquid jar. I’m spending about 5 minutes per day with this unit on average. Most of the grubs have been fed to my pond fish, and some of them have been sent to my BioPod customers in seeding kits.

As the weather gets cooler I’ll monitor the activity of the female black soldier flies that visit the unit to lay eggs. I’ll probably start a new post to record the end of season information.

composter, compost, larvae, fly, flies, biopod