Process manual for the establishment of a Black Soldier Fly (Hermetiaillucens) production system Richard Newton Contents . The conditions for this part of the production are the most critical. These issues will be discussed in more detail in the relevant sections of the manual.1. However certain hurdles must be overcome and decisions must be made regarding the nature of the system. . For this to be feasible. an efficient breeding enclosure must be set up which will provide eggs and young larvae which may be grown in a separate vessel. Introduction This process manual offers a simple guide to the setting up of a black soldier fly (BSF) production system. that the larvae are most nutritious before the onset of pupation which poses problems as to their collection at this stage and secondly regarding the optimum use of the feedstock and hence the biofertiliser. to ensure that mating occurs and that ovi-position is performed in a satisfactory manner. The further growing of the larvae is the least difficult to maintain. Firstly. It gives the most basic information on the materials and technical knowhow to establish a working system which can be used for small scale production of BSF larvae and the bio-fertiliser co-product. the feeding action and metabolism of the larvae will generate some heat which allows their culture in colder climates.2. 2.1 Incubation The eggs of the BSF are about 1mm long and a creamy yellow colour in appearance.3 Adult stage. at which point the animal leaves the feed source and searches out a dry. After mating has occurred. many of them will die shortly after reproduction. their primary focus is to mate and lay eggs. Pupation takes around a week at optimum temperatures until emergence occurs.2 Larval and pupal stages BSF larvae are photophobic and will bury themselves in the nearest organic material and start feeding on it. After this. The availability of water can increase their lifespan to around 12 days whereas in absence of water they may only survive for around 6 days. including faeces. Some larvae may take over two months to reach full size if both temperature and feed availability are low. The adult flies are photophilic and require strong daylight spectra as well as temperatures between 25°C and 35°C to encourage mating to occur. larvae will reach full size of around 20 to 25mm in about 4 weeks. although they will drink water or other liquids if available. they take around 4 days to incubate and hatch. All stages take longer at lower temperatures and larvae will take much longer to grow if the availability of feed stocks is low. This is the pre-pupa stage. they become dark and their skin becomes harder. but although growth is somewhat temperature dependent. They will happily feast on most animal matter. At this point they seek out organic matter of either plant or animal origin. they stop feeding. mating and ovi-position After the adults emerge from their pupal cases. 2. dark place in which to pupate and transform into an adult. and the softer less cellulosic plant matter whether decaying or not but they tend only to feed on high cellulose plant matter once it has begun to decay. With optimum temperatures. Large spaces for courtship are preferable but not absolutely essential as successful mating can be encouraged in illuminated boxes of less than 1m3. The optimum temperature for BSF larvae is also in the upper 20s centigrade. In any case. ovi-position may occur up to . Life Cycle of Hermetia illucens 2. They cannot readily feed on plant matter high in lignin or animal bones. At optimum conditions of around 20° to 30° centigrade. However. the range of organic material which they are able to digest is extremely varied and they are voracious feeders which can easily consume their own body weight in a day. They do not feed. dry crevices such as in wood or corrugated cardboard. the continual production of BSF requires two separate containing areas which operate dependently on each other. Black soldier fly breeding in captivity Essentially. BSF are widely reported to not breed in temperatures below 25°C. wood-chips or other dry. therefore. The enclosure should also be in an area where it is protected from other elements such as the wind and rain. Given Figure 3. 3. The breeding area. close to sources of decaying matter are preferred. Flies will emerge from the pupal cases in around two weeks. needs to be placed in a location where strong sunlight will enter for a substantial part of the day to provide both light and heat. The adult flies are housed in side mesh enclosures. supported on metal frames. The most important criteria for successful BSF breeding are a strong source of daylight and a high temperature. The photograph above shows breeding enclosures in Ghana. Some residue from BSF larvae feeding can often act as an attractant to egg laying. absorbent material. The eggs from this are transferred to a larvarium within which the larvae grow to full size and provide pupae for the next generation of broodstock. This can also be achieved in temperate regions using a suitable light bulb. For this. The flies should be supplied with water which will prolong their life.1 BSF breeding enclosures Figure 3.2 days after. which allow adequate space for the flies to perform courtship rituals. A population of adult flies should be maintained by allowing a proportion of larvae to pupate and adding the pupa to a container full of sawdust.2 Female BSF laying eggs in strips of corrugated cardboard . The insectarium maintains a population of adults which act as a broodstock. but is also more labour intensive. a dedicated nursery system can be adopted where eggs are transferred to a small box specifically for the hatching of the eggs.1. This method provides a larger level of control over the breeding and incubation. Alternatively the goal may be to dispose of waste quickly. containing a small amount of feeding medium as shown in fig 4. Figure 4. from which they can be removed periodically. After a couple of days the female flies will seek a dry crevice in which to lay their eggs and can be attracted to lay eggs where desired by supplying a medium such as corrugated cardboard near some food waste and some residue (fras) from the feeding activities of the larvae.e. The larvarium may take several forms. However eggs should be incubated in dry conditions. the flies should mate naturally within a couple of days of emergence. If the goal is to produce fresh larvae. The advantages Figure 4. 4. Holding vessels can be constructed in such a way that pre-pupae will be directed to collection vessels. typically around 4 days after the eggs have been laid. the contents of the box can be transferred to the larvarium. This can be achieved by suspending the cardboard strips above the feedstock so that the larvae will fall into it upon hatching. depending on the goal of the project. The natural tendency for BSF pre-pupae to leave the feed medium and search out a dark. producing pre-pupae and biofertiliser along the way. showing ramps for self of this are that the vessels can be harvesting .enough light and adequate temperature. i. They may then be kept at 4°C for several weeks until such time as they are required. lends itself to selfharvesting. Larval on growing and collection Once sufficient eggs have been laid. Once this has occurred.2 Larvarium box design. when they are fully grown but before pupation has begun. Alternatively. they can be transferred to the larvarium. dry place to pupate.1 Nursery box containing developing eggs the larvarium may take the form of many small vessels which are easy to control and from which the larvae may be separated at the correct stage. 3 shows manual sorting of larvae from Figure 4. Therefore it is desirable to have more than one holding vessel. The downside of this is that they must be collected in some way. so that continuous production can be maintained.larger and less monitoring is required. Typically it will take around 4 to 6 weeks for larvae to fully grow and reach the pre-pupa stage. Residue and fras The quality and quantity of the left over material depends on the nature of the feedstock substrate and how many times it is used. This could be achieved in a similar set up to figure 4. Having said this. Alternatively. which is anti-nutritional. The quality of the residue is sometimes considered to be too high in nutrients for direct use on crops as a biofertiliser. In order to collect large quantities of larvae quickly. Therefore to provide a high quality feed material for livestock. This may be desirable. The pre-pupae and pupae have much tougher skins with high chitin content. Another method might involve adding water to the larvarium vessel. the residue may be used only once. either by hand or an automated system must be used. residue The level of labour intensity is very high. 5. The water could be reused and finally used to water crops. which means that it will pass through the guts of several generations of BSF larvae. adds complexity to the process because they will not typically self-harvest. some raw materials are not readily ingested such as woody materials. if the goal is to produce optimum nutritional quality of the larvae. Harvesting the BSF larvae. One method which may be used is to use a rotating drum with a mesh screen. the larvae must be collected before pupation occurs. Figure 4. At this time newly hatched larvae may be added for a further few weeks. Feed stock may be added and pre-pupae collected continuously until such time as the vessel is full.2. Substrate may be left inside the larvarium vessel for several weeks or months before it is finally removed. other techniques need to be employed which have yet to be established.3 Manually sorting BSF larvae from the feed larvarium production boxes in Ghana. prior to pupation. however. Some dilution of the residue may be required and some evidence . using manual sorting. depending on the objectives of the operation. therefore the addition of new larvae should be halted around 2 months prior to cleaning out the residue feed and fras. BSF larvae will naturally crawl out of the feed medium if the amount of water is sufficient. has suggested that further treatment can be beneficial. Regulations 8. Constraints . Higher nitrogen tends to lead to venting of ammonia and other nitrogen gases where as poor oxygen availability leads to anaerobic processes and the release of methane. Some vermi-culture trials have proven positive using the red worm. which BSF larvae do not. 6. The nature of the BSF residue is that it is naturally high in nitrogen and may require bulking out with high carbon materials to compost efficiently. Foetida spp. Ideal composting conditions require a C:N ratio of around 30:1 and sufficient oxygen exchange. This may include composting or vermi-composting. The red worm helps to break down the organic material further and make it more bio-available to plant species. but both require further management to be viable. The use of BSF as a livestock feed 7.
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