Black Soldier Fly Larvae

As promised, here's an article on Black Soldier Fly Larvae, (BSFL).  Rather than go into a long and drawn out "how to", I will refer you to what I consider the best online source for learning all about BSFL, Jerry's Black Soldier Fly Blog.  I met Jerry online a few years ago on a fishing forum when he was just getting started with BSFL.  Glad to see he stuck with it.

My experiences with BSFL started about thirteen years ago at my work place.  Some bags of dog food at the city kennels had gotten wet when a trash can lid blew off during a storm and a few weeks later while cleaning up flood debris I discovered one of the bags crawling with BSFL but did not know at the time what they were.  My only thought was "the biggest maggots I ever saw"!

Since that time with online vermiculture, meeting Jerry with his BSFL projects and other composting and gardening activities I have come to learn quite alot about them and the Black Soldier Fly, parent to the BSFL.

Now I have raised fly larvae and I have raised BSFL and can assure anyone they are two totally different creatures entirely. The pest fly larvae or maggots are some nasty creatures but have their place in nature.  BSFL on the other hand are larvae of a fly but it is not a pest fly to humans and does not feed during its life as a fly, nor does it even have any mouth parts like a pest fly.  Its only purpose during its seven or eight day life as a fly is to mate and lay eggs.  It poses no threat to humans in any way and does not transmit any disease as do pest flies.

Some things I particularly like about BSFL versus pest fly larvae is the fact that they can be raised on a variety of feed sources, like fruit and vegetable wastes or grain products.  They will eat just about anything that once lived except cellulose and bone.  They do not stink like pest fly larvae, depending of course on what they are fed and a well maintained rearing system. They purge their gut and secrete a self disinfecting enzyme when leaving the food pile in search of a place to pupate which lends to various devices of clean "self harvesting".  These traits, as well as their high protein, calcium, fat content and mass reproduction make them a perfect candidate for the fishbait & reptile feed trade as well as Entomophagy in my opinion.

Today I needed a break from building mealworm enclosures so I decided to play with a coroplast design of a BSFL bin.  Here's the base, built entirely from one 4' x 4' coroplast sheet, 4mm thick.  All geometric cuts and folds from one piece so it's not patchwork from smaller pieces which helps with the sturdiness, except the center brace that's heat welded to the inside walls as well as all seams where flaps overlap being heat welded...

Kind of looks like a really short boat haha!  Will construct a lid and add a few more vent holes that also serve as adult fly entry points to lay eggs and we'll be ready for BSFL season. 

That's the drawback to raising BSFL.  To my knowledge the adult fly does not do well in captivity situations so if one has winter time there is a BSFL season and that being summer of course.  Still, a plus to this is that BSFL will delay pupating during cold weather and survive as larvae, continuing to process foodstuffs if in an insulated enclosure, even in very cold conditions.  This allows for continuing the colony from season to season once a colony is established and nature takes its course.

Starting a BSFL colony can be tough, especially if one has little or no native population.  In this case, one can purchase BSFL from a variety of online sources to start a bin.  The same chemical signals given off by an active BSFL that repel gnats and pest flies also serves as an attractant to adult Black Soldier Flies in the area.  If there are none in the area, one needs to then allow their purchased larvae to pupate and turn into adult flies near a wooded area where they will gather and mate among the trees and bushes.  Having your bin close by and ready with offerings of spent coffee grounds which they love will assure a good start to your colony and allowing some to escape will ensure there will always be adults around.

Having learned alot about BSFL over the years, I see no difference in raising them on leftover human foods to cook and eat as human food, just as if I were to raise, cook and eat a mealworm.  The BSFL might actually even be a cleaner bug on its own merit than any we could produce through all our efforts.

Updated pics of the almost finished coroplast BSFL bin...

Sliding removable access door on top and hanging larvae catch basin.  Just a few minor details to do but for all practical purposes it's complete. 

The plan for this is to set it up over a composting worm bin.  BSFL generate quite alot of liquid the worms can utilize, as well as the BSFL frass.  A simple layer of aluminum screen will separate the two.  Since worms and BSFL commonly inhabit the same compost pile, I don't have a problem if some mingle.  The BSFL likely will not be interested in the cardboard worm bedding and stay topside where their food pile is while some of the small worms may migrate upward and probably be eaten.  Liquid should soak into the worm bedding through the mesh and worms can pick away at the frass which pokes through.  Will just have to try it and see how it goes.

Here's a link to a DIY BSFL bin using an old 55 gallon plastic drum and some lumber...

  http://gardenpool.org/beneficial-insects/black-soldier-fly-composter-automatic-chicken-feeder

Here's another BSFL bin I started put together yesterday, 3/14/12. Not sure about what to do with the bottom yet. Might try agricultural capillary mat for reverse capillary action as a way of controlling moisture in the bin.  I'm not sure but don't see why it wouldn't work.  A slit for the mat to protrude out from the sides should act like a wick, drawing moisture from the bottom of the bin to the outside air to evaporate.  Worth a try.