Of course

In biology, flies are typical "completely metamorphosed insects". Its life goes through four stages: egg, larva (maggot), pupa and adult, and the morphology of each stage is completely different. The breakdown is as follows:

1. Eggs: Eggs are milky white, banana-shaped or oval, and about 1 mm long. There are two ridges on the back of the egg shell, and the membrane between the ridges is the thinnest, from which the larvae emerge when hatching. The development time of the egg stage is 8 ~ 24 hours, which is related to the environmental temperature and humidity. The egg does not develop below 13℃, and dies below 8℃ or above 42℃. In the following range, the incubation time of eggs is shortened with the increase of temperature: 21 hours at 22℃; At 25℃, it takes 16 ~ 18 hours; At 28℃, it takes 14 hours; At 35℃, it only takes 8 ~ 11 hours. The humidity of growth substrate also affects the hatching rate of eggs: when the relative humidity is 75% ~ 81%, the hatching rate is the highest; When it is lower than 65% or higher than 85%, the hatching rate is obviously reduced. 2. Larvae: Larvae of flies, commonly known as maggots, has three ages: the 1-year-old larva has a body length of 1 ~ 3 mm and only a rear valve. After molting, it becomes 2 years old, 3 ~ 5 mm long, with front valve and 2 cracks in rear valve. Molting again is the third instar, 5 ~ 13 mm long, and the rear valve is 3 cracks. The body color of fly maggots changes from transparent and milky white to milky yellow at 1 ~ 3 years old until they mature and pupate. The 3rd instar larvae are oblong and conical, with a tapering front end and a truncated rear end, with no eyes and no feet. The life characteristics of fly maggots are that they like drilling holes, are afraid of strong light, and live in seclusion in the dark and dark places of breeding materials all day long. It has a variety of food habits, and all kinds of rotten fermented organic matter are its delicious food. Larval stage is a key period in the life of flies, and its growth and development is directly related to the individual size and reproductive efficiency of breeding flies. The main factors affecting the growth and development of fly maggots are as follows: ① Temperature: its level is directly related to the development time of fly maggots. The optimum environmental temperature (medium temperature) is 34 ~ 41℃, and the development period can be shortened to 3 ~ 3.5 days. When the temperature is 25 ~ 31℃, the development period is 4 ~ 6 days; When the temperature is 21 ~ 25℃, the development period is 5 ~ 9 days; When the temperature is 16℃, the development period is as long as 17 ~ 19 days. The lowest temperature during development is 8 ~ 12℃, and when it is higher than 48℃, it will die. ② Humidity: The suitable environmental humidity of 1 ~ 2 instar fly maggots is 61% ~ 81%, and the optimum humidity is 71% ~ 81%. The suitable humidity of the third instar fly maggot is 61% ~ 71%, and it will not develop normally if it exceeds 81%. It can be seen that the development of fly maggots needs a certain degree of humidity, but the higher the better. In production practice, the suitable humidity is 65% ~ 71%; When it is less than 41%, the development of fly maggots is stagnant, pupation is rare, and even the fly maggots die. ③ Food: One of the important ecology of fly maggots is omnivorousness, and they feed on the spot in their habitats. Someone once found 76,411 maggots and pupae in 1.5 square meters of pig manure! Animal feed, plant feed and even protein in microorganisms are all nutrients that fly maggots like to ingest. The quantity, quality, fermentation temperature and even water content of food are directly related to the development effect of fly maggots. The 3rd instar fly maggots stop eating when they are mature, and often leave the breeding ground at low temperature of 15 ~ 21℃ and low humidity, and drill to the nearby loose soil to pupate. Someone once found thousands of pupae of houseflies in the cracks of the damaged cement floor at the root of the wall in a winery. ④ Ventilation: Ventilation is beneficial to the growth and development of fly maggots. In garbage dumps, fly maggots are often distributed in corners and walls with large gaps. Mastering the growth characteristics of the above-mentioned fly maggots can be used to guide the production practice and is of great benefit to improve the breeding efficiency of fly maggots. 3. Pupa: Pupa is the third metamorphosis in the life history of flies. It is barrel-shaped, that is, it surrounds pupae. Its body color changed from light to dark, and finally turned into chestnut brown, with a length of 5 ~ 8 mm. The pupa shell is constantly metamorphosed, and once the embryonic form of the fly is formed, it enters the eclosion stage. During eclosion, the fly alternately expands and contracts by the frontal sac of the head, squeezing out the head end of the pupa shell and crawling out, and reaching the ground surface through loose sand or other culture materials. From pupa to emergence, it is called pupa stage. The external factors that affect the growth and development of pupae are as follows: ① Temperature: After the third instar flies mature, they tend to pupate in a slightly lower temperature environment. But when the temperature is lower than 12℃, the pupa stops developing; When the temperature is higher than 45℃, the pupa will die. In a suitable range, with the increase of temperature, the pupal period is shortened accordingly. At 16℃, it takes 17 ~ 19 days; At 21℃, it takes 11 ~ 11 days; At 25℃, it takes 6 ~ 7 days; At 31℃, it takes 4 ~ 5 days; At 35℃, it only takes 3 ~ 4 days, which is the best development temperature. The characteristics of pupae are relatively cold-resistant. According to the experiment, the pupa of housefly returned to normal room temperature after 4 days of cold storage in the refrigerator with the temperature of 1℃ and the environmental humidity of 85%, and the emergence period was only delayed by 1 days compared with the normal pupa period. Cold storage for 3 days in the above environment will not reduce the eclosion rate. (2) Humidity: According to the experiment, the humidity of the optimum culture medium suitable for pupa development is 45% ~ 55%, which is higher than 71% or lower than 15%, which will obviously affect the normal emergence of pupa. If the pupae are soaked in water, the longer the time, the lower the pupation rate of fly maggots and the lower the emergence rate of pupae. Someone once fished 1,111 pupae from liquid garbage, and after being transferred to a dry environment, none of them emerged as adults. It is worth mentioning that if the nutrients in the culture of fly maggots are insufficient and the maggots barely pupate without full development, the pupae can also hatch into flies, but more than 95% of the adult flies are male, only eat food and do not lay eggs, and all die in about a week. Therefore, the maggots used for seed storage and pupation must be fattened with sufficient nutrients, and the greater the proportion of females. Only when there are more female flies, the amount of eggs laid will be guaranteed and the yield will be stable. 4. Adult flies: Adult flies emerging from pupae need to go through several stages of "static-crawling-stretching-spreading wings-body wall hardening" before they can develop into adult flies with the ability of flying, feeding and reproduction. Musca domestica, which just emerged from pupa, has a soft and light gray body wall, its wings have not been unfolded and its frontal sac has not been retracted. Later, the wings spread, the epidermis hardened and the color deepened. After 1 ~ 1.5 hours, the wings could fly. Under the condition of 27℃, adult flies began to move and eat 2 ~ 24 hours after emergence. Its ecological habits are as follows. (1) Feeding habits and longevity The feeding habits of flies depend on their species. There are those who specialize in sucking nectar and plant juice, and those who specialize in cannibalism, animal blood or animal wound blood and eye and nose secretions. The common houseflies, Chrysomya megacephala, Lucilia sericata, Calliphora, and Hemp flies belong to omnivorous flies, that is, they widely eat human food, excretions and excretions of livestock and poultry, kitchen scraps and organic substances in garbage. They have a strong tendency to the taste and fishy smell of sugar, vinegar, ammonia. According to the research, if the female flies are simply supplied with water, sugar and carbohydrates, although they can grow, their ovaries cannot develop and lay eggs; Only by feeding protein food or a variety of amino acids can normal spawning be achieved. If female houseflies are fed with royal jelly, the prophase of oviposition can be shortened and the amount of oviposition can be increased. The factors that affect the life span of flies are temperature, humidity, food and water. The optimum temperature is 25℃ ~ 33℃ and air humidity is 61% ~ 71. Female flies live longer than male flies, with a life span of 31 ~ 61 days; Under laboratory conditions, it can be as long as 112 days. Flies can live for half a year under low temperature wintering conditions. The adaptability of flies is very strong. The breeding of flies can be roughly divided into human excrement, livestock excrement, corrupt animals, corrupt plants, garbage and sewage. Fly maggots have strong adaptability, and can breed in almost all the above six types, especially in livestock manure and fermented plants, and secondly in human manure and corrupt animals. ⑵ Active and perched flies are insects that are active in the daytime and have obvious phototaxis. At night, it stays still. Activities and habitats depend on fly species, season, temperature and region. In some seasons, stable rot flies, summer flies and city flies will also invade the house. Chrysomya megacephala, Lucilia sericata, Calliphora, Bactrocera, Hemp Fly, etc. are mainly active and live outdoors. The activity of flies is greatly influenced by temperature. It can only crawl at 4 ~ 7℃, fly at 11 ~ 15℃, feed, mate and lay eggs above 21℃, especially active at 31 ~ 35℃, stop moving at 35 ~ 41℃ due to overheating, and die at 45 ~ 47℃. Flies are good at flying The flight speed can reach 6 ~ 8 kilometers per hour, and the highest flight speed is 8 ~ 18 kilometers per day and night. However, it usually moves within the radius of 111 ~ 211 meters of the breeding ground, and most of them do not exceed 1 ~ 2 kilometers. The way flies overwinter is quite complicated. It can overwinter not only in pupa state, but also in the form of fly maggots and adults. In the northern cold zone and temperate zone, there are no active houseflies in nature, but there are still adult flies in artificially heated rooms, and vegetable greenhouses often become the birthplace of a large number of flies in the next spring. In the south of the Yangtze River and parts of North China, the average temperature in winter is below 1℃, so flies can spend the winter in pupa state skillfully, and maggots of dormant female flies covered with livestock manure can also be found in a few areas. In the subtropical region of South China, the average temperature is above 5℃, and flies can continue to breed without dormancy. ⑶ Male and female are respectively 1. From their individuals, the smaller individuals in the group are generally males, while the larger individuals are generally males and females; Look at their bellies: the bellies of male flies are small and flat, while those of female flies are large and round; 3. Look at their asses. They are divided into females: the asses of male flies are round, while those of female flies are pointed. (4) Mating and reproduction At a suitable temperature, the male housefly can be sexually mature and mated at 18-24 hours after emergence and 31 hours after emergence of the female housefly. The mating time is usually from 5: 11 to 7: 11 in the morning. Sensitive sense of smell, sex pheromone and vision are all important factors to promote the mating of male and female flies. A pair of mating houseflies can stay in one place for a long time, crawl together and fly together, and the effective mating time is as long as 1 hours. Most houseflies mate only once in their lives. The semen of a male fly can be stored in the fertilization sac of a female fly for a long time, which stimulates oviposition, and continues to fertilize the fly eggs for 2-3 weeks without mating with another male fly. This is rare among other insects. This is the important reason why flies are prolific. The peak of spawning is from 17: 11 to 19: 11 every day. The length of the pre-spawning period of female flies (that is, the time from emergence to first spawning) is closely related to the environmental temperature: 9 days on average at 15℃, only 1.8 days at 35℃, and no eggs can be laid below 15℃. After mating, the female flies often climb into the breeding gaps such as human and animal feces, and extend the ovipositor tube to lay eggs in the depths of the breeding, so as to fully protect the eggs. Flies have amazing fertility. According to the observation, the houseflies in the laboratory lay about 111 eggs in each batch, and 1 female flies can finally lay 11-21 batches, with a total of 611-1111 eggs. In nature, every female fly can lay eggs in 4 ~ 6 batches in her lifetime, with an interval of 3 ~ 4 days. Each batch lays about 111 eggs and 411 ~ 611 eggs in her lifetime. Even in North China, houseflies can breed 11 ~ 12 generations a year. According to the most conservative estimate, each female fly can produce 211 offspring, so it takes only 11 generations for 111 female flies to breed, and the total number of flies will reach 2 trillion! 5. Although the natural enemy flies have strong reproductive ability and prosperous families, 51% ~ 61% of future generations died prematurely due to natural enemy attacks and other disasters. There are three kinds of natural enemies of flies: first, predatory natural enemies, including frogs, dragonflies, spiders, mantis, ants, lizards, geckos, insect-eating flies and birds. Chicken manure is the breeding ground of domestic flies and stable flies, but there are often vicious giant mites and salamanders, which will prey on fly eggs and maggots in the manure. Second, parasitic natural enemies, such as wasps, wasps and other parasitic bees, often lay eggs in maggots or pupae, and then feed on maggots and pupae after hatching larvae. It was found that 61.4% of the pupae of the wasp were invaded by parasitic bees and died prematurely. The third is the natural enemy of microorganisms. Japanese scholars have found that Bacillus Morita can inhibit the breeding of flies, and Chinese scholars have also found that if the spores of "Tricholoma flies" fall on flies, they will infect flies with Tricholoma flies. All these are worthy of the attention of fly maggot breeders.

Cage-net breeding of flies in ordinary houses is a widely used technology in fly farms in China in recent years. This technology requires heating facilities in the room, otherwise, when the indoor temperature is less than 27℃ in autumn, winter and spring, the fecundity of flies will be seriously reduced. When the room heating temperature is low, especially in the north, flies have to be pupated to protect insects in winter, which leads to the interruption of fly breeding and a significant decline in economic benefits. Breeding flies in plastic greenhouse successfully solved this problem, which can make flies produce continuously all year round, and improve the breeding benefit several times, thus becoming a very promising technology.

Flies have the following requirements in terms of temperature, humidity and illumination:

The most suitable temperature for flies is 27℃ ~ 31℃. At 8 ~ 12℃, flies can move, but they can't mate or stand on food. They can only land on the ceiling and wall and don't move. At MINUS 5℃, they die in 3 ~ 5 days. The temperature required by fly larvae is higher than that of adults. The optimum temperature for its fastest development is 35℃, and it stops moving at minus 1 ~ 2℃ and dies at minus 5 ~ 6℃. When the temperature is too high, its increasing speed is reduced by half compared with the normal temperature. It is suitable for fly larvae to require food temperature of 31 ~ 35℃. In terms of humidity, adults require indoor humidity of 55% ~ 61%. When the humidity is too high, fly legs and bodies are easy to get wet and hinder activities. The humidity required by the larval growth period is 65% ~ 71%. Flies like to move in bright places, and the greater the brightness, the greater the activity. Artificial breeding flies should have a lighting device in the room, and the light should be more than 11 hours a day.

Harm of flies. Flies are harmful to human beings because they carry a variety of pathogenic microorganisms. The body surface of flies is hairy, and the foot pads can secrete mucus. They like to crawl in feces, urine, vomit and corpses of human beings or livestock for food, and it is very easy to attach a large number of pathogens, such as Vibrio cholerae, Salmonella typhi, Shigella dysenteriae, Hepatitis B, Polio, Ascaris eggs, etc. It often stays on human body, food and tableware, and has the habit of rubbing its feet and brushing its body when it stops. The pathogens attached to it will soon pollute the food and tableware. When flies eat, they first spit out crop fluid and dissolve the food before inhaling, and they will eat, spit and pull. In this way, the pathogens originally eaten in the digestive juice will be spit out together, polluting the food it has eaten, and people will get sick if they eat these foods again and use contaminated tableware. The epidemic of cholera, dysentery and bacterial food poisoning are directly related to the spread of flies. < P > Prevention and control of flies

1. Domestic garbage is packed in discarded plastic bags, and it is clear every day, so don't let flies contact and lay eggs.

2. When taking out the garbage, it must be put into the bucket (box, car) and covered, and removed in time.

3. Eliminate garbage and sanitary dead ends in front of and behind residents' houses, inside and outside units.

4. Restaurants and stalls should have fly prevention and extermination facilities, and garbage should be put into barrels and covered in time.

the life span of flies. A fly can live for about 1 months in midsummer. But at a relatively low temperature