CATDOLL : CATDOLL: Are maggots insects? Flies are insects, are larvae?

The most standard insect, things with six legs are 90% insects

Introduction:

fly

【Introduction to Flies】According to statistics from the late 1970s, there are more than 120,000 species of Diptera insects in 132 families worldwide, of which there are more than 34,000 species of flies in 64 families. In Fuzhou city, there are 74 species in 4 families, 38 genera. The main fly species are houseflies (right), city flies, silkworm green flies, and big-headed golden flies.

Flies have the physiological characteristic of laying eggs for life after mating once. A female fly can lay eggs 5-6 times in her lifetime, with about 100-150 eggs laid each time, and up to 300 eggs at most. It can reproduce 10-12 generations in a year.

[Life History] In biology, flies are typical "complete metamorphosis insects". Their life cycle goes through four stages: egg, larva (maggot), pupa, and adult, and the morphology of each stage is completely different. The details are as follows:

1. Eggs: The 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. The larvae drill out from here when hatching. The development time of the egg stage is 8 to 24 hours, which is related to the ambient temperature and humidity. The eggs will not develop below 13°C, and will die below 8°C or above 42°C. Within the following range, the incubation time of the eggs shortens with the increase of temperature: 20 hours at 22°C; 16 to 18 hours at 25°C; 14 hours at 28°C; and only 8 to 10 hours at 35°C. The humidity of the growth medium also affects the hatching rate of the eggs: the hatching rate is highest when the relative humidity is 75% to 80%; the hatching rate is significantly reduced when it is below 65% or above 85%.

2. Larvae: The larvae of flies are commonly known as maggots, and there are three stages: the first-stage larvae are 1 to 3 mm long and have only the posterior spiracles. After molting, they become the second-stage larvae, 3 to 5 mm long, with anterior spiracles and 2-cleft posterior spiracles. After molting again, they become the third-stage larvae, 5 to 13 mm long, with 3-cleft posterior spiracles. The body color of maggots changes from transparent and milky white to milky yellow from the first to the third stage until they mature and pupate. The third-stage larvae are long conical, with a pointed front end and a truncated rear end, without eyes or feet. The life characteristics of maggots are that they like to drill holes, fear strong light, and live in dark places where they breed all day long. They are polyphagous, and all kinds of corrupt and fermented organic matter are their delicious food. The larval stage is a critical period in the life of flies. The quality of their growth and development is directly related to the individual size and reproductive efficiency of the fly.

The main factors affecting the growth and development of maggots are as follows:

① Temperature: Its level is directly related to the length of the development time of fly maggots. The optimum environmental temperature (culture medium temperature) is 34-40℃, and the development period can be shortened to 3-3.5 days; when the temperature is 25-30℃, the development period is 4-6 days; when the temperature is 20-25℃, 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 the development period is 8-12℃, and it will die if it is higher than 48℃.

② Humidity: The suitable humidity for 1st to 2nd instar maggots is 61% to 80%, and the best humidity is 71% to 80%. The suitable humidity for 3rd instar maggots is 61% to 70%, and they cannot develop normally if it exceeds 80%. It can be seen that the development of maggots requires a certain humidity, but the higher the better. In production practice, the suitable humidity is 65% to 70%; below 40%, the development of maggots stagnates, pupation is extremely rare, and even leads to the death of maggots.

③ Food: One of the important ecological features of fly maggots is that they are omnivorous and they feed locally in their habitats. Someone once found as many as 76,400 fly 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 consume. The quantity, quality, fermentation temperature and even water content of food are directly related to the development effect of fly maggots. After the third-instar fly maggots mature, they stop eating. Under low temperature of 15-20℃ and low humidity, they often leave the breeding place and drill into the nearby loose soil to pupate. Someone once found thousands of housefly pupae in the cracks of the damaged cement floor at the base of the wall in a winery.

④ Ventilation: Air circulation is conducive to the growth and development of maggots. In garbage dumps, maggots are often distributed in corners and bases with large gaps.

??Mastering the growth characteristics of the above-mentioned fly maggots and using them to guide actual production will be of great benefit to improving the efficiency of fly maggot farming.

??3. Pupa: Pupa is the third metamorphosis in the life history of flies. It is barrel-shaped, i.e., the peri-pupa. Its body color changes from light to dark, and finally turns into chestnut brown, 5 to 8 mm long. Metamorphosis continues inside the pupa shell. Once the prototype of the fly is formed, it enters the eclosion stage. During eclosion, the fly relies on the alternating expansion and contraction of the frontal sac on its head to push open the head end of the pupa shell and crawl out, passing through loose sand or other culture materials to reach the ground surface. From pupation to eclosion is called the pupal stage.

??The external factors that affect the growth and development of pupae mainly include:

① Temperature: After the third-instar flies mature, they tend to pupate in a slightly lower temperature environment. However, when the temperature is below 12°C, the pupae stop developing; when the temperature is above 45°C, the pupae will die. Within the appropriate range, as the temperature rises, the pupal period shortens accordingly. At 16°C, it takes 17 to 19 days; at 20°C, it takes 10 to 11 days; at 25°C, it takes 6 to 7 days; at 30°C, it takes 4 to 5 days; at 35°C, it only takes 3 to 4 days, which is the optimal development temperature. The characteristic of pupae is that they are relatively cold-resistant. According to experiments, housefly pupae were refrigerated in a refrigerator at a temperature of 1°C and an ambient humidity of 85% for 4 days and then returned to normal room temperature. The emergence period was only delayed by 1 day compared to the normal pupal period; refrigeration for 3 days in the above environment did not reduce its emergence rate.

② Humidity: According to experiments, the best culture medium humidity for pupae development is 45% to 55%. Higher than 70% or lower than 15% will significantly affect the normal emergence of pupae. If pupae are soaked in water, the longer the time, the lower the pupation rate of fly maggots, and the emergence rate of pupae also decreases. Someone once fished out 1,000 fly pupae from liquid garbage, and after transferring them to a dry environment, none of them emerged as adult flies.

??It is worth mentioning that if the nutrients for cultivating fly maggots are insufficient, the fly maggots will pupate without fully developing. Such pupae can also hatch into adult flies, but more than 95% of such adult flies are males, which only eat food and do not lay eggs, and all die in about a week. Therefore, fly maggots used for seed pupation must be raised with sufficient nutrients to make them fatter, and the proportion of females will be greater. Only when there are more female seed flies can the egg-laying capacity be guaranteed and the yield be stable.

? 4. Adult flies: Adult flies that have emerged from pupae need to go through several stages of resting, crawling, stretching, spreading wings, and hardening of the body wall before they can develop into adult flies that have the ability to fly, feed, and reproduce. The body wall of a housefly that has just emerged from a pupa is soft and light gray, with its wings not yet spread and its frontal sac not retracted. Later, the wings will be extended, the epidermis will harden and the color will deepen. After 1 to 1.5 hours, the wings will be able to fly. Under the condition of 27℃, adult flies will start to move and feed 2 to 24 hours after emergence. Its ecological habits are as follows.

? (1) Diet and lifespan

??The feeding habits of flies depend on their species. Some specialize in sucking nectar and plant juices, while others specialize in eating human and animal blood or blood from animal wounds and secretions from the eyes and nose. The common houseflies, golden flies, silky green flies, blowflies, and flesh flies are omnivorous flies, which means they widely feed on human food, livestock and poultry secretions and excrement, kitchen scraps, and organic matter in garbage. They have a strong tendency to sugar, vinegar, ammonia, and fishy smells. According to research, if female flies are simply supplied with water, sugar, and carbohydrates, they can grow, but they cannot develop or lay eggs; only by adding protein food or multiple amino acids can they lay eggs normally. If royal jelly is used to feed female houseflies, the early egg-laying period can be shortened and the egg-laying amount can be increased.