Black Soldier Fly Larvae

Photo from Wikimedia Commons

I hope the title of this post doesn't put anyone off.  If you're not fundamentally squeamish about insects, I promise there's nothing terribly icky about what I've got to say today.

Included in my formal list of goals for this year is the project of trying to feed our laying hens more and more with food we produce ourselves.  We've already got well established routines that provide some of the chickens' food, such as kitchen scraps, trimmings from the garden, feeding them Japanese beetles and squash bugs in the proper seasons, and gleaning acorns for them in the fall.  Still, we end up buying a few 80-pound bags of feed for them each year.  This is grown organically, fairly local to me, and milled by the farmer that grows it, so on that score I feel pretty good about it.  But it's a 45-minute drive to buy the feed, and the price (though much cheaper than the nasty pelletized chicken feed from Tractor Supply) has been nudging up steadily ever since I started buying it.  This feed easily accounts for more than half of the hens' caloric intake over the course of the year.

So I've been looking a bit harder at what we might do to close the gaps in our homestead economy and nutrient cycles.  Worms from our vermicompost are an excellent possibility, but I'm going to leave that project for another post.  Right now I'm going to talk about the Black Soldier Fly, which is probably the coolest idea easily adapted for use by very small scale homesteaders I've come across in a long time.  I have this tendency to think that if I've heard of some cool idea, then everyone else already has too.  But I've gotten comments from time to time that ask for more detail on stuff I mention in an off-hand way.  So I'm going to review what I know about this species and how those with small backyard poultry flocks can partner with it to their advantage.

The Black Soldier Fly is well established in many parts of the world, including most of North America in hardiness zone 7 or warmer.  Though it is a fly, it's a world apart from the common housefly in terms of the nuisance factor.  The adult phase of this insect's life, the only time it can fly, is very brief and devoted solely to reproduction.  The adult BSF doesn't even have a working mouth, so it cannot bite or eat and is not attracted by food, except as a resource for the next generation of BSF.  Even so, the mated female BSF does not land on food.  She seeks to lay her eggs nearby - not on - a food source, where the newly hatched larvae will be able to land on the food and begin feeding.  BSF larvae can consume small amounts of meat, but this is not a species that specializes in carrion.  Mostly what she's looking for is decomposing plant matter.  In fact, they may already be resident in your compost heap.  Once her eggs are laid, the adult fly has accomplished her mission in life, and dies shortly after.  The males also die shortly after mating.  The larvae remain on the food source as they pass through several sub-stages of growth, until they are ready to pupate, at which point they seek to burrow into the earth to complete their development into adults.  So you can see that there is little purpose or opportunity for the BSF to interact with humans in any way, unless we deliberately facilitate such an interaction.  Indeed, even if you live in a region with a BSF population, it's entirely feasible that you have never noticed these insects before, since they have little interest in us, and such short life spans in adult form.

The point at which we would want to intervene in the life cycle of this insect is when the larvae are fully grown and ready to pupate. Clever people have designed a clever contraption for harvesting the mature larvae at just this stage.  Or rather, using the BSF's instincts in order to have it harvest itself.  The BioPod is a custom built bucket system that provides an exit route for the larvae leading to a closed container, which makes feeding them to poultry or other livestock trivially easy.

I'm going to post another piece soon about the knockoff BSF composting buckets I'm working on.  What I want to dwell on a little more at this stage is the idea of partnering with this species.  Although in my formal goals for this year I wrote that I'm not committing to adding another species to our homestead, that was an oversight.  In reality, the Black Soldier Fly is another species I very much plan to work with.  It may not look like livestock, just as our red wriggler worms for the vermicompost bin didn't look like livestock.  Perhaps they're not.  But they will be a new species for us, and partnering with them will involve a learning curve.  I see the cultivation of these insects as one more item in the self-sufficiency toolbox; one more thing that reduces our dependence on fossil fuels.  For without fossil fuels it would be very difficult for the farmer to harvest the grains that make up our purchased feed, and very difficult for us to go and buy them multiple times per year.

It may seem grotesque to call my intended relationship with BSF a "partnership."  After all, it looks pretty exploitative from one perspective.  But in reality, I don't see this as ethically any different than keeping other species for food.  I will be establishing an insect where it doesn't currently exist, and responsible not only for feeding each generation, but also maintaining a "wild" population that survives to adulthood in order to reproduce and create the next generation.   After obtaining a starter colony, I'll need to heavily "seed" our garden soils with ready-to-pupate larvae.  This will reduce my usable harvest in the first year.  But with luck, a good population will take root right in the backyard, and continue to take advantage of the shelter and food the composting buckets will provide for them. From what I've read, I will very much need to actively tend the compost buckets.  I expect to derive both animal feed and a small amount of compost tea from this partnership.  In other words, the BSF will become part of the system of this homestead.  I'm always looking for ways to increase the diversity of species, and the connections between them, on our tiny piece of land.

Sooner or later I'll post more on the buckets themselves.  In the meantime, having read this post, would you humor me please, by participating in my poll on Black Soldier Fly composting?  It's on the sidebar of my blog.  I'm curious how many of you have heard of BSF cultivation before, and what your attitudes towards it might be.