Hermetia illucens, known colloquially as the black soldier fly, is a widespread fly of the family Stratiomyidae. Black soldier fly larvae are commonly utilized in composting systems due to their ability to rapidly break down food waste. In recent years, H. illucens has increasingly been gaining attention because of its hyperaccumulation of protein and fats via consumption of renewable substrates.
Distribution This species is native to the Neotropical realm, but in recent decades has spread across all continents, becoming virtually cosmopolitan.
It is present in parts of North America and Europe, including the Iberian Peninsula, southern France, Italy, Croatia, Malta, the Canary Islands, and Switzerland, and on the Black Sea coast of Russia in Krasnodar.
It can also be found in the Afrotropical realm, the Australasian realm, the east Palaearctic realm, the Nearctic realm, North Africa, Southern Africa, and the Indomalayan realm, including South Asia such as India and Pakistan.
Description
The adults of H. illucens measure about long. These medium-sized flies have a predominantly black body, with metallic reflections ranging from blue to green on the thorax and sometimes with a reddish end of the abdomen. The second abdominal tergite has translucent areas, from which the Latin specific epithet derives. The head is wide, with very developed eyes. The antennae are about twice the length of the head. The legs are black with whitish tarsi. The wings are membranous; at rest, they are folded horizontally on the abdomen and overlapped.
H. illucens is a mimic fly, very close in size, color, and appearance to the organ pipe mud dauber wasp and its relatives. The mimicry of this particular kind of wasp is especially enhanced by the fly's elongated and wasp-like antennae, pale hind tarsi, and the presence of two small, transparent "windows" in the basal abdominal segments that make the fly appear to have a narrow "wasp waist". Black soldier fly larvae can be differentiated from blowfly or housefly larvae by a thin gray-black stripe on their posterior ends.
Lifecycle
An adult female lays approximately 200 to 600 eggs at a time. These eggs are typically deposited in crevices or on surfaces above or adjacent to decaying matter such as manure or compost, and hatch in about 4 days. Freshly emerged larvae are long, being able to reach a length of and weight of by the end of larval stage. The larvae are able to feed on a wide variety of organic matter, adapting to diets with different nutrient content. Studies using artificial diets indicate that larval survival and bioconversion efficiency depend strongly on substrate hydration levels and macronutrient balance. The larval stage lasts from 18 to 36 days, depending on the food substrate provided to the larvae, of which the post-feeding (prepupal) stage lasts around 7 days. The larval stage can be prolonged by months due to low temperature or lack of food. The pupal stage lasts from 1 to 2 weeks. Adults can live typically 47 to 73 days when provided with water and food, such as sugar in captivity or nectar in the wild, or survive for about 8 to 10 days on fat reserves gathered during larval stage when water is provided.
Human relevance and use Neither larvae nor adults are considered to be agricultural pests or disease vectors. Black soldier fly larvae play a role similar to that of redworms as essential decomposers in breaking down organic substrates and returning nutrients to the soil. The larvae have voracious appetites and can be used for composting household food scraps and agricultural waste products.
Additionally, black soldier fly larvae are an alternative source of protein for aquaculture, animal feed, and pet food.
The larvae are produced and processed in industrial-scale insect factories globally by biotechnology companies such as LIVIN farms InnovaFeed, and Protix, the latter operating the world's largest insect factory farm in the Netherlands.Forbes/Davide Banis (14 June 2019): Can Using Insects As Animal Feed Reduce The Climate Impact Of Meat Production?.
As decomposers in composting Black soldier fly larvae (BSFL) are used to compost waste or convert the waste into animal feed. Waste streams include fresh manure and food wastes of both animal and vegetable origin. Fly larvae are among the most efficient animals at converting biomass into feed.
When the larvae have completed their larval development through six instars, they enter a stage called the "prepupa" wherein they cease to eat, and tend to migrate toward cool, dark, and dry substrates to pupate. This prepupal migration instinct is used by grub composting bins to self-harvest the mature larvae. These containers have ramps or holes on the sides to allow the prepupae to climb out of the composter and drop into a collection area.
Black soldier fly larvae are beneficial for use as composters in the following ways:
Their large size relative to houseflies and blowflies allows BSFL to prevent houseflies and blowflies from laying eggs in decaying matter by consuming larvae of other species. This means compost systems inhabited by BSFL may be a more human-friendly way to handle food waste when compared to those inhabited by houseflies and blowflies which typically produce a much worse smell. They are not a pest to humans. Unlike houseflies, adult black soldier flies have greatly reduced sponging mouthparts, meaning they can only consume liquids such as flower nectar, although they typically do not eat at all. Unlike houseflies, which regurgitate food along with digestive enzymes, adult black soldier flies therefore do not spread pathogens or diseases. They are not attracted to human habitation or foods. As a detritivore and coprovore, the egg-bearing females are only attracted to rotting food or manure. Black soldier flies do not fly around as much as houseflies. They have less expendable energy due to their limited ability to consume food as adults. They are very easy to catch and relocate when they get inside a house, as they do not avoid being picked up, they are sanitary, and they neither bite nor sting. Their only defense seems to be hiding. When using a wet grub bin that collects or kills all the pupae, the black soldier fly population is easy to reduce by killing the pupae/prepupae in the collection container, before they become adult flies. They may be killed by freezing, drying, manually feeding to domestic animals, putting the collection container in a chicken coop for automatic feeding, or feeding to wild birds with a mouse/pest-proof feeder. Significant reductions of E. coli O157:H7 and Salmonella enterica were measured in hen manure after larvae were added to the manure. They quickly reclaim would-be pollutants: Nine organic chemicals were greatly reduced or eliminated from manure in 24 hours, making them a potential tool for bioremediation. They quickly reduce the volume and weight of waste: larval colonies break apart their food, churn it, and create heat, increasing compost evaporation. Significant amounts of waste are also converted to carbon dioxide respired by the grubs and symbiotic/mutualistic microorganisms. The use of BSFL in a compost system typically reduces the volume of compost by around 50%.
Aside from protein production, fly larvae also produce frass. Fly larval frass is a granulated and odorless residue that can be used as organic fertilizer directly or through conversion by earthworms.
As feed Black soldier fly larvae are used as feed for pets and livestock animals. The harvested pupae and prepupae are eaten by poultry, fish, pigs, lizards, turtles, and even dogs. The insect is one of the few insect species approved to be used as feed in aquaculture in the EU.Commission Regulation (EU) 2017/893 of 24 May 2017 amending Annexes I and IV to Regulation (EC) No 999/2001 of the European Parliament and of the Council and Annexes X, XIV and XV to Commission Regulation (EU) No 142/2011 as regards the provisions on processed animal protein
At the pupal stage, black soldier flies are at their nutritional peak. They can be stored at room temperature for several weeks, and their longest shelf life is achieved at .
The sector faces financial challenges. In January 2025, Agronutris entered a safeguard procedure to restructure its debts and Ÿnsect was seeking a takeover. In November 2025, the largest insect farm in Northern Europe, Enorm Biofactory, went bankrupt, despite €55 million in funding.
A 2024 analysis indicated that the majority of investment in insect farming had been directed towards companies farming black soldier fly larvae (59% of disclosed investments). However, a significant proportion of these investments (around 36%) have gone to firms that have ceased operations or entered court-supervised restructuring. While investment growth was rapid prior to 2021, recent trends show a 65% decline between 2022 and 2024, reflecting a challenging investment environment.
As human food Records of human consumption of H. illucens are difficult to find.
In 2013, Austrian designer Katharina Unger invented a table-top insect-breeding farm called "Farm 432" in which people can produce edible fly larvae at home. It is a multi-chambered plastic machine that looks like a kitchen appliance and can produce of larvae or two meals in a week.
The taste of the larvae is said to be very distinctive. According to Unger, "when you cook them, they smell a bit like cooked potatoes. The consistency is a bit harder on the outside and like soft meat on the inside. The taste is nutty and a bit meaty.
For producing grease BSFL can be used to produce grease, which is usable in the pharmaceutical industry (e.g. in cosmetics,Insects as an alternative source for the production of fats for cosmetics surfactants for shower gel), thereby replacing vegetable oils such as palm oil. It can also be used in fodder.EOS magazine, February 2020Kempen Insect Valley's Circular Organics
For producing chitin BSFL can be used to produce chitin. Chitin is used in shipping as an agent against biofouling. It is also used in water purification. Chitin also has potential as a soil amendment, to improve soil fertility and plant resilience.
For producing organic plant fertilizer Material left over after the larval waste decomposition process (frass) consists of larval faeces, shed larval exoskeletons, and undigested material. Frass is one of the main products from commercial black soldier fly rearing. The chemical profile of the frass varies with the substrate on which the larvae feed, but in general, it is considered a versatile organic plant fertilizer due to a favorable ratio of three major plant nutrients: nitrogen, phosphorus, and potassium. BSFL frass is commonly applied by direct mixing with soil and considered a long-term fertilizer with slow nutrient release. Plant trials have also found short-term fertilizing effects comparable to fast-acting, synthetic fertilizers. In addition to its nutrient contribution, BSFL frass can carry further components that are beneficial for soil fertility and soil health, such as chitin from the shed exoskeletons of the larvae. Finally, the use of BSFL frass as a fertilizer can effectively alter the soil microbial community composition, which plays a crucial role for soil fertility.
Debate is going on whether the frass from BSFL rearing can be used as a fertilizer in a fresh state or has to undergo further composting before its application. Some assume that further composting would lead to the reduction of potential phytotoxic properties. In the European Union, insect frass has to be treated for one hour at before commercialization for safety reasons, the same as other animal manure products.