The black soldier fly (BSF) Hermetia illucens is a native non-pest fly with a very short life as an adult. The main objective of the adult fly is to breed and lay eggs. It does not feed (no mouth parts), is totally harmless, docile, does not have a stinger, and is rarely seen. When the adult is observed, it is often mistaken for a mud dobber (wasp), but the white feet and slow flight pattern will give it away as a fly. After mating, the gravid female will lay eggs (approximately 300-500) in crevices above or adjacent to the food waste, but will never actually touch the waste herself. This is one of the reasons these flies are non-pathogen vectors – they never touch the waste nor are they interested in your food. When the eggs hatch, the larvae will fall into the waste. These larvae are detritivors and as such they will consume almost anything we would, including meat and dairy. They are voracious and can devour food waste within 24 to 36 hours! Much faster than worms in vemicomposting and compost bins. Not to mention, BSF can bio-convert a wider variety of food waste than either worms or compost piles. Studies have shown that a colony of BSF can convert 100 lbs of kitchen scraps into 5 lbs of friable compost (good worm food or soil amendment), a few quarts of nutritious compost-like tea, and approx. 15-20 lbs of self-harvesting prepupa (grubs). Needless to say, the end product of this process are the grubs and not compost.
When the larvae have completed their larval development through six instars (growth stages), they enter a stage called “prepupa”. At this point, the BSF will cease to eat, empty their guts, their mouth parts change to an appendage that aids climbing, and they seek a dry, sheltered area to pupate. It is this prepupal migration instinct which causes the grubs to self-harvest up the ramp provided and then drop into a collection container. This is the most nutritious stage within the BSF life cycle. The larva have been storing protein, fat, calcium and other nutrients to insure the adult will survive to mate and lay viable eggs. Thus making them a very nutritious food for songbirds, chickens, fish, pigs, herps, and “you”!