Black Soldier Fly Larva Harvester

Black soldier fly larva are voracious decomposers. Here’s a video of a some larva completely devouring a hamburger over the course of five hours. And here’s a video of some chickens completely devouring some black soldier fly larva.

Black soldier flies have some curious qualities that make them particularly well suiting for cultivating their larva as fodder for your feathered friends:

  1. As stated before black soldier fly larva are voracious. They will eat fish and meat scraps that you would not typically put in your compost pile for fear of attracting larger vermin. They break down organic material into usable compost extremely rapidly.
  2. As an added bonus black soldier fly larva eat the eggs of other fly species who foolishly lay their eggs in rotting organic material. This severely diminishes your population of house flies and fruit flies. I had a compost pile that was beset with fruit flies until the black soldier fly larva moved in.
  3. When a black soldier fly larva is ready to pupate(turn its adult form) it attempts to crawl away from its brethren/feeding frenzy to a place where it can pupate in peace lest it be devoured while it is indisposed.
  4. A black solider fly adult doesn’t have a mouth which means it won’t be buzzing around splitting time between stealing bites off of your picnic lunch and sampling that juicy pile of manure nearby. Black soldier fly only live long enough to mate and lay eggs. They do have a sense of smell to find some rotting organic matter near which(not in which) to lay their eggs.

You can harness these curious qualities to create a system where black soldier fly larva will prosper and self harvest when the time is right. If you do a web search there are loads of diy black soldier fly harvester designs. Here’s one I made based on several videos and websites I researched.

Main materials include the storage container, 1″ PVC pipe, (2) PVC elbow, PVC cap, (2)pipe brackets, Machine bolts and nuts, Velcro and vinyl corner trim.

Cutting slots in the drain pipe. This will allow some air to get into the bottom of the compost

Cutting a drain hole in the storage bin

Inserting drain pipe

The vertical drain pipe helps get air into the bottom of the compost pile.

Lots of things going on here. The bottom half of the bin will be filled with rotting organic mater and black soldier fly larva. When a larva is ready to pupate it will attempt to exit. The Velcro around the top breaks any surface tension stopping any attempts to climb the walls. Eventually the larva will climb the ramp (corner trim) and fall into the PVC pipe. Underneath the outlet of the PVC pipe will be a bucket.

To allow/encourage adult black soldier flies to lay their eggs in the bin I drilled small entrance holes in the bin above the Velcro. I then attached a piece of corrugated cardboard to the lid of the bin. Those holes are a prefect size for a lady black soldier fly to lay her eggs.

So, I’ll put some fragrant compostables in the harvester and hope some black soldier flys wander by. Black soldier flies are warm weather creatures so it may a little late in the year. I will let you know how it goes.