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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 a 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.

solider

Posted 03 May 2009 † Jerry § Raising black soldier fly larvae § The BioPod § Vermiculture and BSF composting ‡ Comments (9) ° Tagged: , , , , , ,

Appreciating Bug Guide.net

An interesting and informative site.

Visit BugGuide.net

bug-guide-about-page

Posted 26 September 2008 † Jerry § Understanding black soldier flies ‡ Comments (4) ° Tagged: ,

Black solidier fly larvae-variation in growth rate

I recently collected a newly laid clutch of black soldier fly (Hermetia illucens)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.

solider

Posted 24 September 2008 † Jerry § My first year raising BSF § Raising black soldier fly larvae § Understanding black soldier flies § Vermiculture and BSF composting ‡ Comments (0) ° Tagged: , , ,

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 (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

Posted 15 September 2008 † Jerry § Understanding black soldier flies § Utilizing black soldier fly larvae ‡ Comments (11) ° Tagged: ,

Black soldier fly composting in the frigid north

frigid north

Black soldier flies (Hermetia illucens) are common in tropical and subtropical regions, but their range extends into many 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 without heating it is possible because the churning action and digestion of the black soldier fly grubs 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. You can think of it like a diesel engine, if it gets cold then it’s hard to get it started again.

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 will probably be a challenge for a novice, but it’s worth tying because at worst you’ll learn more about this fascinating creature. If you aren’t up to the challenge just yet then you can enjoy BSF culturing up to the point where the weather in your area makes it difficult and then resume in the spring. If you can store some or all of the compost through the winter it should make attracting the BSF easier in the spring.

Process more food scraps, harvest less grubs

The time it takes BSF larvae to mature increases in cold weather from the usual few weeks to a period of up to several months. I’ve maintained BSF grubs in the juvenile stage (light color, actively feeding) for five months through winter keeping the unit outdoors with some insulation. The same individual grubs will eat all winter which enables you to continue bio-composting without the need to replenish the colony with visiting females.

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

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

solider

Posted 16 August 2008 † Jerry § Raising black soldier fly larvae § The BioPod § Understanding black soldier flies ‡ Comments (46) ° Tagged: , ,