By Faith Maiyo
Introduction
Black soldier fly (Hermetia illucens) is from Stratiomyidae family in the Diptera order. It is one of the most beneficial and most widespread form of insect farming in the world. The larvae are an excellent source of food for many animals like poultry, bait for fish and pigs. At different stages of their life cycle, especially at larvae stage, the following activities are observed; they consume large quantities of food wastes, agricultural waste products are decomposed and eventually converted into manure which restores soil fertility besides the maintenance of a healthy environment. As an essential decomposer, the black soldier fly reduces the volume and weights of any waste obtained, reduce potential pollutants such as organic chemicals in manure, prevent houseflies from laying eggs in the waste, cause a significant reduction of E. coli and Salmonella enterica in chicken manure and are not attracted to human habitation and foods. They inhibit flies and houseflies from flying around.
Life cycle of black soldier flies
BSF has five growth stages in its lifecycle: egg, larvae, prepupal, pupae and adult. The larval stage is further divided into phases called instars. An instar is defined as the period between each molting of their exoskeleton. BSF has five instar stages. All the adult fly’s nutritional requirements are obtained during its larval stage and adult flies survive on their fat reserves obtained as maggots. BSF, have an estimated life cycle of 38 – 40 days from egg to adult. Once they hatch, they migrate down into the fresh rearing substrate (chicken manure, cow dung, rabbit dung, pig manure, market waste, kitchen waste etc.). Waste consumption rates appear to depend on the larvae size and stage as larvae in the first and second instar feed more.
The 1st instar is white in colour and its segment is not clear.
The 2nd instar the segment is visible.
The 3rd instar is off white in colour, but the segments are not clear.
The 4th instar is white cream in colour, segments are well visible, and the larvae has a protein content of between 42-47%.
The 5th instar is beige in colour and the larvae has a protein content of between 42-50%.
The prepupal stage
This is a breeding stage, and the pupa is black in colour. At this stage, the pupa does not feed and does not moult.
The Pupae stage
During this stage, the pupae is rigid and dormant.
After the adult emerges from the pupal case, mating can occur. At this stage, the adult does not feed on anything they survive on the fat reserves, and they suck water which facilitates successful flying and mating process and enough light and preferably sunlight is required. Egg laying usually occurs 3-4 days after mating at a temperature of between 28-30 ℃. Females have a long and sharp tail that aids in laying eggs and seeks out an area that is secure and close to a food source to deposit their fertilized eggs. Thus, farmers are required to provide the adult cages with containers holding the egg laying devices (concrete pipes or wooden materials which are commercially available) with odour producing substance to attract females BSF to laying there.
BSF adults have a lifespan of between 14-16days. A single female BSF would deposit a mass or cluster of about 1000 to 1500 bunch of eggs. In absence of good lighting there will be low egg production. The laying mediums is usually positioned vertically over an oviposition attractant, to prevent the laying mediums from getting soaked in the substrate, such as wet kitchen waste or well-moistened poultry layer mash for wild trapping as well as in laboratory colony. They are also provided with clean drinking water soaked on cotton wool to prevent them from drowning.
Breeding cage for mating process
Black soldier flies require well-lit cages. The best cage made of the mesh is important since it allows proper ventilation and protects the flies from predators. For lighting purposes, it is advised to be reared in a greenhouse to mimic a natural source of light.
Procedure for harvesting eggs
Eggs collection can be done daily. However, the traps can be checked regularly or weekly if not collected daily until sufficient numbers of BSF larvae are found feeding inside the containers.
- Untie the net
- Shake the net to prevent flies hoovering around not to escape
- Enter your head onto the net
- Start by removing the water trough and remove flies that are on the through
- Remove the feeding trough, and make sure there are no flies hoovering around it or which are tuck inside the troughs.
After harvesting the eggs, they are weighed in analytical scale(g) and sold or transferred to hatching trays that are labelled date of egg collection and hatch date and contains moist feed. Eggs take about 4 days to hatch, and then the larvae will take roughly 21 days to pupate. Pupae take 14 days to emerge as adult BSF’s.Larvae formed starts feeding on the moist feeds by sucking the substrate, the moisture content of the resource is important as it affects BSF development. Moisture contents outside the optimum range will cause adverse effects. The larvae require approximately 12 – 14 days to complete development. They happen to feed on any waste until they reach the 5th instar. At the 5th instar, the pupa is harvested and moved into the adult cages.
Harvesting of larvae
The adult BSF lays its eggs in rotting fruits, vegetables, manure or other agricultural waste. Within two weeks, the eggs hatch and turn into mature larvae. Once the larvae have developed completely, through the six stages, they enter a stage called the prepupa. While this stage, they stop to eat, empty their stomachs and their mouth parts change to an attachment that helps in climbing. During this period, they prefer dry sheltered area to pupate. More often, such dry places are in compost bins where self-harvest of the mature larvae can be done. These containers have holes on the sides to allow the prepupae to climb out of the compost bin and drop into a collection area.
Black soldier fly value addition.
Black soldier fly larvae (BSFL) are used to compost waste or convert the waste intoanimal feed. Fly larvae are among the most efficient animals at converting biomass into feed. Black soldier fly can also be formulated into feeds for poultry, pig, and fish.