What are the breeding methods for houseflies? Detailed introduction to breeding methods

    At present, there are two methods for breeding houseflies in China, namely cage rearing and room rearing. Each of the two breeding methods has its own advantages. Cage rearing provides better isolation and is more hygienic, and can create suitable rearing conditions, but the utilization rate of the housing is not high; room rearing can improve the utilization rate, and the equipment is simple, saving labor and cost, and is more suitable for large-scale continuous production, but management is inconvenient, and adult flies easily escape.
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    (1) Room rearing. Fly room design and rearing room construction: Generally, for a single-story house with an area of 15 to 20 sq m, iron gauze netting and glass windows are installed on the house, and exhaust fans are installed on the windows. Indoors there is a heating fire wall or stove to keep the temperature between 25 and 30 °C, and the relative humidity of the air is adjusted to about 70%. Iron gauze netting is installed on the door and covered with a black cloth curtain to prevent flies from escaping. A newly built fly room should be a row of single-row flat-roofed housing facing south. A closed corridor is set on the north side, with an operation room in the middle, with doors at the front and back. The fly rooms on both sides have doors on the north side, and entry is through the corridor from the back door of the work room. On the south side there are 1.7 m × 1.8 m glass windows, and each room has an area of 38.5 sq m (2.5 m × 5.5 m  × 2.8 m), equipped with screen doors, screen windows, exhaust fans and an underground flue. This kind of fly room has a suitable bay size, high utilization rate, abundant sunlight, and good ventilation. The closed corridor on the north side can effectively prevent adult flies from escaping, and in winter it can also buffer the invasion of the north wind and help with indoor heat preservation. According to local specific conditions, it can also be designed as a simple combined greenhouse and housing for breeding adult flies. A cement tank is built outdoors, and livestock and poultry manure and human excrement are poured into the tank to attract flies to lay eggs, which hatch into maggots; feed is added regularly and maggots are scooped out for use. This method is the simplest and most economical, but the yield is relatively low and it is greatly affected by the environment. When rearing adult flies in a room, after culling the adult flies, the floor and surrounding walls should also be thoroughly cleaned and disinfected with ultraviolet light for 2-3 hours.

    (2) Cage rearing. The equipment used for rearing is relatively simple, mainly including: fly cages, egg-laying jars, drinking jars, feed trays and cage racks. Fly cage: The size is determined according to the scale of housefly rearing. For example, it can be sewn from white rubberized plastic window screening (preferably mosquito netting), with specifications of 50 cm × 50 cm × 50 cm. The 8 corners of the cage are fixed to a wooden or iron frame with straps or iron rings so that the fly cage is fixed into a certain shape. A cage of this size is suitable for rearing 10,000 to 12,000 adult houseflies. A round hole with a diameter of about 20 cm is opened on one side of the cage, one end of a cloth sleeve is sewn onto the round hole, and the other end serves as the operation opening. Usually the cloth sleeve is tied shut with a rubber band or tied in a knot. During operation, the hand is inserted through the cloth sleeve to change water, add feed, and so on. A rectangular frame of 65 cm × 80 cm × 90 cm can also be made from wooden strips or 6.5 mm steel bars, and then plastic gauze, iron gauze or fine-mesh copper gauze is covered around it. Similarly, a cloth sleeve opening is installed at the lower corner on one side of the fly cage for feeding, watering, and taking and placing egg-laying pads (Figure 24). Fly cages should be placed indoors in a place with ample light but not direct sunlight. Each fly cage should also be equipped with a feed tray and 1 drinking jar, and when egg laying begins, an egg-laying jar needs to be added at the appropriate time. Feed tray: Various plates (enamel plates, disposable plastic plates, etc.) can be used with milk powder and brown sugar (food for adult flies) placed on them, allowing most adult flies to feed. Drinking jar: Place 1-2 dishes or bowls with a diameter of about 13 cm in each fly cage, with a piece of water-soaked sponge inside for houseflies to drink. Egg-laying jar: After the pupae emerge as adult flies, the egg-laying jar can be placed on the fourth day. The egg-laying jar can be the same as the drinking jar and needs a certain height. Generally 3 to 4 cm is good. This can maintain the humidity of the culture medium. Place 1-2 per cage. Cage rack: Design the cage rack yourself according to the size of the fly cage, the rearing quantity and the size of the fly-rearing room (Figure 25). The cage rack can be made of wood, or welded from steel bars or angle iron. The size only needs to be enough to hold the fly cages. To save space, several layers are generally stacked, as long as it is convenient for the operator. Taking a 50 cm × 50 cm × 50 cm fly cage as an example, the cage rack can be designed as follows: total height about 180 cm, divided into 3 layers, each layer higher than 50 cm and longer than 100 cm. Each layer holds 3 cages, for a total of 6 cages. The lower legs are 20 to 30 cm high. Because the temperature near the ground is lower, the space more than 30 cm above the ground should be used as much as possible.   

    The fly-rearing room required for cage rearing must have constant-temperature equipment to allow rearing and reproduction in all four seasons. The roof is about 2.5 m high, and the walls and roof should preferably have insulating material to help with heat preservation. A simple heat preservation method is to use a 1,000-watt heating electric furnace or electric heater connected to a temperature controller. Where conditions permit, an air conditioner can be installed to maintain the temperature. The temperature is best controlled at 24 to 30 °C, and must not be lower than 20 °C or higher than 35 °C. The indoor humidity is best controlled at 50%-70%. A 40-watt fluorescent lamp or a 100-watt light bulb should be installed in the middle of the room.