Intrusive, annoying, disgusting - just a few epithets that we give flies. Their reproduction is so fast that it terrifies us. On the body of flies are millions of different microbes. And yet, these insects are not only a symbol of unsanitary conditions and dirt. This is an important link in food chains and organic waste destroyers. The significance of flies in nature and our lives, the life cycle and stages of propagation of flies and their contribution to the development of scientific thought will be discussed in the article.
Flies are different
Speaking of flies, we mean representatives of the order Diptera , class Insects (Insecta), of which there are about 75 thousand species. Some species are harmless, others sting and bite. There are flies, the reproduction of which passes through several stages, and there are also viviparous.
They live all over the globe. But for all their diversity, in the article we will talk about synanthropic species of flies - those who live in close proximity to us. We know them very well, these are:
- Housefly or housefly (Musca domestica).
- Blue (Calliphora vicina) and green (Lucilia sericata) meat flies.
- Fruit fly or Drosophila fruit (Drosophila melanogaster).
In addition to these most famous representatives, another 5 species of giant flies, representatives of the Hippoboscidae family, live on the territory of Russia. In appearance, they are similar to house flies, but the difference is that the lighters (autumn, horse, sheep) are active bloodsuckers. They sting people and animals in late summer and autumn.
And yet most flies feed on any organic matter. But they prefer sweets more. Moreover, they distinguish sugar from saccharin accurately. Although there are specialized species. For example, the larvae of cheese flies (Piophila casei) feed exclusively on cheese.
A few words about the "sacred cow" of geneticists
Small fruit flies that invariably appear on rotten fruits have made a huge contribution to the development of genetics - the science of the laws of inheritance and variability. It was Drosophila that was chosen as the object of research by the great geneticist Thomas Hunt Morgan (1866-1945). The rapid reproduction of Drosophila flies, large 4 chromosomes and pronounced sexual dimorphism made these insects a favorite object of experiments.
Everyone knows who has studied well at school about his laws of sex-linked inheritance of traits and the phenomenon of crossing over.
Called "Lord of the Flies," Thomas Morgan went down in history as one of the founders of practical genetics. And when you get rid of these insects, remember that it is to them that we owe medical and genetic counseling, genetic engineering, and many other achievements of modern practical geneticists.
General biological characterization
Despite the diversity of species of these insects, they have similar features in structure, life and reproduction. The housefly is an excellent representative, on the example of which we will consider the biology features of real flies.
The massive body, covered with chitinous cover, is divided into the head, chest and abdomen. On the head are three simple and two complex facet eyes, a pair of antennas (antennae) and the oral apparatus (proboscis ending in a pillow-labella).
On the chest of the fly there are two true wings and two ground beetles (reduced wings) and 3 pairs of jointed limbs. The paws are covered with small sensitive hairs, and end with a sole with suction cups - that's why they can "walk" on the ceiling. Two wings of the fly allow it to develop a flight speed of up to 20 km / h.
On the abdominal oval shape, in the last segments, there are copulative organs of the male and ovipositor in the female.
The whole body is covered with hairs, and on the sides of each segment there are spiracles - tracheal openings that provide insect respiration. Body hairs and special cone receptors provide the fly with clear coordination.
Life cycle and features
Flies are insects with complete transformation. This means that the reproduction and development of the fly goes through several stages, namely the egg, larva, pupa, and imago. All stages of the life cycle are distinguished by their habitat, mode of nutrition, and morphology.
Reproduction of flies (meat, domestic and others) begins from the moment of mating at the adult stage. Males attract females with the help of sound signals that they emit by hummers. Fertilization occurs inside the body of the female.
On average, after 2 days, the female lays up to 200 eggs and is again ready for mating. If all the eggs of one fly survived, then in her whole life, which lasts up to 2 months, the female would give life to 3 thousand descendants. These are 8-9 generations that would increase the number of descendants of the first fly to 5 trillion individuals. Here is such an amazing speed of breeding flies.
The complete cycle of transformations from egg to imago in flies takes 10-20 days and depends on temperature.
Stages of development: a brief description
For a general understanding of the development, breeding of flies and ways to combat them, it is important to know the conditions for the development of all stages.
The first stage of development of a fly is an egg. This is the shortest period of the life cycle (up to 24 hours), but also the most important. Flies make masonry in the waste of our life, corpses, garbage pits, rotten foods.
A larva emerges from the egg, which looks like a thin white thread. The larva actively eats for 5-7 days, increasing its weight by 800 times. Then it acquires a brown color, and the fly proceeds to the next stage of its development.
Pupa is a passive stage of the life cycle that lasts up to 5 days. At this time, a significant metamorphosis (transformation) occurs inside the chrysalis - a young imago forms from a shapeless larva.
Value in nature
Flies become carriers of diseases involuntarily. And in nature, their value is enormous. Starting with the fact that these insects and their larvae are an important link in the food chain.
In addition, without flies, our planet would be covered with a layer of rotting organic matter. By repeatedly passing through organic waste, the larvae of the fly return mineral substances and chemical elements to the cycle of substances in nature.
Many representatives of these dipterans are pollinators of plants. And some (for example, the kytri of the Asilidae family) are active predators that regulate the number of other insects. And, by the way, they are used as biological weapons against pests of forests and fields.
Dangerous disease vectors
Flies are carriers of pathogens of human infectious diseases. On the surface of their body is up to 6 million, and in the intestine up to 28 million microbes that can retain their pathogenic properties. Anthrax, typhoid fever, dysentery, cholera, tuberculosis, diphtheria - this is just a small list of what flies carry.
Insects can carry parasitic protozoa, fungal spores, helminth eggs, and even ticks. Zhigalki carry 6 types of trypanosomes (causative agents of trypanosomiasis, sleeping sickness) and 3 types of spirochetes (causative agents of syphilis, Lyme disease). They spoil food, making them completely unsuitable for consumption, and simply look unaesthetic in borsch. So always separate flies from cutlets - this is good for your health!
And some flies breed
Fly larvae are a source of excellent feed protein that can compete with bone meal. And there are already examples of the development of such an insect business in Russia. In 2016, such a mini-farm was presented at the exhibition of VDNH. The author of the development is Igor Istomin, the head of the New Technologies company.
The project of his farm for the breeding of larvae of flies and the production of environmentally friendly and highly effective bio-feeds and organic fertilizers from them, is based on the use of what nature has created for millions of years. On the chitinous bristles of the flies there is a disinfecting secret, and the larvae contain pure protein and immunomodulators.
“Mushinaya Farma” is an example of non-waste and environmentally friendly production at an agricultural enterprise, when all the waste is recycled and returned in the form of bioadditives to animal feed and organic fertilizers.