CATDOLL : CATDOLL: Morphological characteristics of flies

Flies belong to the order Diptera, and are small to medium in size. Their antennae are shorter than the total length of their head and thorax, with only three segments. The last segment has a whip at the end or a feathery bristle on the back of the last segment, called an antennal awn (arista). There are two compound eyes and three simple round eyes. The mouthparts are of the licking and sucking type. The forewings are membranous and used for flying. The hind wings degenerate into halters, which are hidden under the wing petals at the base of the forewings. Flies are holometabolous insects. Their life cycle goes through four stages: egg, larva (maggot), pupa, and adult. The morphology of each stage is completely different. The female lays eggs on decaying organic matter such as carrion or feces, and the larvae feed on these decaying matter after hatching. Some species of flies are ovoviviparous, such as the flesh fly. Eggs

The eggs are milky white, banana-shaped or oval, and about 1mm long. There are two ridges on the back of the eggshell, and the membrane between the ridges is the thinnest. The larvae will 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℃, and will die below 8℃ or above 42℃. Within the following range, the incubation time of the eggs will shorten with the increase of temperature: 20 hours at 22℃; 16 to 18 hours at 25℃; 14 hours at 28℃; and only 8 to 10 hours at 35℃. 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%.

larva

Larvae are commonly known as fly maggots, and there are three instars: the first instar larvae are 1 to 3 mm long and have only the posterior spiracles. After molting, they become the second instar, 3 to 5 mm long, with anterior spiracles and 2-lobed posterior spiracles. After molting again, they become the third instar, 5 to 13 mm long, with 3-lobed posterior spiracles. The body color of fly maggots changes from transparent and milky white to milky yellow from the first to the third instars until they mature and pupate. The third instar larvae are long conical, with a pointed front end and a truncated rear end, without eyes or legs. The life characteristics of fly maggots are that they like to drill holes, fear strong light, and live in dark places away from light 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 larvae have pharyngeal bones, posterior spiracles, posterior spiracles, and small processes at the end of the abdomen. The third-instar larvae have small heads, hooked claw-like mouths, and are asymmetrical.

pupa

Pupa is the third metamorphosis in the life history of flies. It is barrel-shaped, i.e., the 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.

Adult

The body is 5 to 8 mm long, gray-brown, with hairless, dark red compound eyes. The forehead width of male flies is 1/4 to 2/5 of the eye width; the forehead width of female flies is almost equal to the width of one side of the compound eyes. The antennae are gray-black, short and flat, with short antennae and thick base. There are feathery hairs on both sides of the dorsal and ventral sides, all the way to the tip of the awn, and the lower whiskers are brown-black. The mouthparts are licking and sucking. A thick and short beak can be seen from the outside. It consists of three parts. The base beak is inverted cone shape, the middle beak is thick and short and tubular, and the terminal beak is developed and divided into two petals, which are called labia; the beak can be freely extended. There are 4 black longitudinal stripes on the mesothorax shield, and there are cilia in the central depression of the pronotum side plate. There are no tufts of setae in front and behind the ribs on the axillary petals, and the lower side pieces are hairy in front of and below the posterior valve. The wings are transparent, the wing veins are brown-yellow, the base scales of the front edge veins are yellow-white, and the end of the fourth longitudinal vein is sharply bent forward to form an angle, and its end is close to the end of the third longitudinal vein. The legs are black with grayish-yellow powder. The abdomen is oval and yellow, especially on both sides of the base. There is a wide black vertical stripe in the middle of the abdomen, and the first abdominal plate has cilia. Flies have 6 legs (3 pairs). The front pair is equivalent to the forelimbs of mammals such as humans, kangaroos, monkeys, bears, and pandas. The back two pairs are supporting and exerting power thighs, which are equivalent to the hind limbs of mammals such as humans, kangaroos, monkeys, bears, and pandas.

After the 3rd instar flies mature, they tend to pupate in a slightly lower temperature environment. However, when the temperature is below 12℃, the pupae stop developing; when the temperature is above 45℃, the pupae will die. Within the suitable range, as the temperature rises, the pupal period shortens accordingly. At 16℃, it takes 17 to 19 days; at 20℃, it takes 10 to 11 days; at 25℃, it takes 6 to 7 days; at 30℃, it takes 4 to 5 days; at 35℃, it only takes 3 to 4 days, which is the best 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℃ and an environmental humidity of 85% for 4 days and then returned to normal room temperature. The eclosion period was only one day later than the normal pupal period; refrigeration for 3 days in the above environment did not reduce its eclosion rate. Humidity: The suitable environmental humidity for 1st to 2nd instar fly maggots is 61 to 80%, and the optimal humidity is 71 to 80%. The suitable environmental humidity for the 3rd instar maggots is 61-70%. If it exceeds 80%, they cannot develop normally. 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 65-70%; below 40%, the development of maggots stagnates, pupation is extremely rare, and even leads to the death of maggots.

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 1.5O tons 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 3rd 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.

Ventilation: Air circulation is conducive to the growth and development of fly maggots. In garbage dumps, fly maggots are often distributed in corners and bases with large gaps. Mastering the growth characteristics of the above fly maggots and using them to guide production practice will be of great benefit to improving the efficiency of fly maggot breeding. Humidity: According to experiments, the optimal culture medium humidity for pupal development is 45-55%. Higher than 70% or lower than 15% will significantly affect the normal emergence of pupae. If the 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 these adult flies are males, which only eat food and do not lay eggs, and all die in about 10 days. Therefore, the fly maggots used for seed pupation must be raised with sufficient nutrients to make them fatter, and the greater their female proportion. Only when there are more female seed flies can the egg-laying capacity be guaranteed and the yield be stable.

Adult flies: Adult flies that have emerged from pupae need to go through several stages of "resting - crawling - stretching the body - spreading wings - hardening of the body wall" before they can develop into adult flies with 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, the wings have not yet spread, and the frontal sac has not retracted. Later, the wings will stretch, 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.

Flies belong to the order Diptera, and are small to medium in size. Their antennae are shorter than the total length of their head and thorax, with only three segments. The last segment has a whip at the end or a feathery bristle on the back of the last segment, called an arista. There are two compound eyes and three simple eyes. The mouthparts are of the licking and sucking type. The forewings are membranous and used for flying. The hind wings degenerate into halters, which are hidden under the wing petals at the base of the forewings. Flies are holometabolous insects. Their life cycle goes through four stages: eggs, larvae (maggots), pupae, and adults. The morphology of each stage is completely different. The female lays eggs on decaying organic matter such as carrion or feces, and the larvae feed on these decaying matter after hatching. Some species of flies are ovoviviparous, such as the flesh fly. Eggs

The eggs are milky white, banana-shaped or oval, and about 1mm long. There are two ridges on the back of the eggshell, and the membrane between the ridges is the thinnest. The larvae will 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℃, and will die below 8℃ or above 42℃. Within the following range, the incubation time of the eggs will shorten with the increase of temperature: 20 hours at 22℃; 16 to 18 hours at 25℃; 14 hours at 28℃; and only 8 to 10 hours at 35℃. 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%.

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Larvae are commonly known as fly maggots, and there are three instars: the first instar larvae are 1 to 3 mm long and have only the posterior spiracles. After molting, they become the second instar, 3 to 5 mm long, with anterior spiracles and 2-lobed posterior spiracles. After molting again, they become the third instar, 5 to 13 mm long, with 3-lobed posterior spiracles. The body color of fly maggots changes from transparent and milky white to milky yellow from the first to the third instars until they mature and pupate. The third instar larvae are long conical, with a pointed front end and a truncated rear end, without eyes or legs. The life characteristics of fly maggots are that they like to drill holes, fear strong light, and live in dark places away from light 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 larvae have pharyngeal bones, posterior spiracles, posterior spiracles, and a small process at the end of the abdomen. The third instar larvae have a small head, a hooked mouth, and are asymmetrical.

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, and 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.

Adult

Flies belong to the order Diptera, and are small to medium in size. Their antennae are shorter than the total length of their head and thorax, with only three segments. The last segment has a whip at the end or a feathery bristle on the back of the last segment, called an antennal awn (arista). There are two compound eyes and three simple eyes. The mouthparts are of the licking and sucking type. The forewings are membranous and used for flying. The hind wings degenerate into halters, which are hidden under the wing petals at the base of the forewings. Flies are completely metamorphosed insects. Their life cycle goes through four stages: eggs, larvae (maggots), pupae, and adults, and the morphology of each stage is completely different. The female lays eggs on decaying organic matter such as carrion or feces, and the larvae feed on these decaying matter after hatching. Some species of flies are ovoviviparous, such as the flesh fly. Eggs

The eggs are milky white, banana-shaped or oval, and about 1mm long. There are two ridges on the back of the eggshell, 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℃, and will die below 8℃ or above 42℃. Within the following range, the incubation time of the eggs shortens with the increase of temperature: at 22℃, 20 hours; at 25℃, 16 to 18 hours; at 28℃, 14 hours; at 35℃, only 8 to 10 hours. The humidity of the growth medium also affects the hatching rate of the eggs: the hatching rate is the highest when the relative humidity is 75-80%; the hatching rate is significantly reduced when it is below 65% or above 85%.

larva

The whole body is gray and has a mental illness.