Intrusive, annoying, disgusting are just a few of the epithets we give to flies. Their reproduction is so fast that it terrifies us. Flies have millions of microbes on their bodies. And yet these insects are not only a symbol of unsanitary conditions and dirt. It is an important link in food chains and destroyers of organic waste. About the importance of flies in nature and our life, about the life cycle and stages of reproduction of flies and their contribution to the development of scientific thought - we will talk about all this in the article.
Flies are different
Speaking of flies, we mean representatives of the order Diptera, class Insects (Insecta), of which there are about 75,000 species. Some species are harmless, others sting and bite. There are flies whose reproduction goes through several stages, and there are also viviparous.
They live all over the globe. But with 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, they are:
- Room or house fly (Musca domestica).
- Blue (Calliphora vicina) and green (Lucilia sericata) blowflies.
- Fruit fly or fruit fly (Drosophila melanogaster).
Besides these most famous representatives, 5 more species of Stinger 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 zhigals (autumn, horse, sheep) are active bloodsuckers. It is they who sting people and animals at the end of summer and autumn.
And yet, most flies feed on any organic matter. But they prefer sweets more. Moreover, they distinguish sugar from saccharin unmistakably. Although there are specialized types. For example, cheese fly larvae (Piophila casei) feed exclusively on cheese.
A few words about the "sacred cow" of geneticists
Small fruit flies, which invariably appear on rotten fruit, 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 have made these insects a favorite object of experiments.
On his laws of sex-linked inheritancesigns and the phenomenon of crossing over are known to everyone who studied well at school.
Nicknamed "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 genetic counseling, genetic engineering and many other achievements of modern practical geneticists.
General biological characteristics
Despite the diversity of species of these insects, they have similar features of structure, life and reproduction. The house fly is an excellent representative, on the example of which we will consider the features of the biology of real flies.
Massive body, covered with chitinous cover, divided into head, chest and abdomen. On the head are three simple and two compound compound eyes, a pair of antennae (antennae) and a mouth apparatus (proboscis ending in a pad-labella).
On the chest of the fly are two true wings and two h alteres (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. The two wings of a fly allow it to reach speeds of up to 20 km/h in flight.
On the oval abdomen, on the last segments, are the copulatory organs of the male and the ovipositor of the female.
The whole body is covered with hairs, and on the sides of each segment there are spiracles - tracheal openings that provide breathing for the insect. Body hairs and special receptorscones provide the fly with precise coordination.
Life cycle and features
Flies are insects with complete metamorphosis. This means that the reproduction and development of the fly goes through several stages, namely egg, larva, pupa, adult. All stages of the life cycle differ in habitat, feeding method and morphology.
Reproduction of flies (meat, domestic and others) begins from the moment of mating of individuals at the adult stage. Males attract females with the help of sound signals, which they emit with h alteres. Fertilization takes place inside the body of the female.
On average, after 2 days, the female lays up to 200 eggs and is ready to mate again. If all the eggs of one fly survived, then in her entire life, which lasts up to 2 months, the female would give birth to 3 thousand offspring. This is 8-9 generations, which would increase the number of descendants of the first fly to 5 trillion individuals. This is such an amazing reproduction rate for flies.
The full cycle of transformations from egg to adult in flies takes 10-20 days and depends on temperature.
Development stages: brief description
For a general understanding of the development, reproduction of flies and how to deal with them, it is important to know the conditions for the development of all stages.
The first stage of a fly's development is an egg. This is the shortest period of the life cycle (up to 24 hours), but also the most important. Flies nest in our waste products, corpses, garbage pits, rotten food.
A larva comes out of the egg, which looks like a thin white thread. Larva onfor 5-7 days actively eats, increasing its weight by 800 times. Then it turns brown, and the fly moves on to the next stage of its development.
The 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 pupa - a young imago is formed from a shapeless larva.
Meaning in nature
Flies become carriers of diseases involuntarily. And in nature, their importance is enormous. Since these insects and their larvae are an important link in the food chain.
Besides, without flies, our planet would be covered with a layer of rotting organic matter. Repeatedly passing organic waste through themselves, fly larvae return minerals and chemical elements to the cycle of substances in nature.
Many representatives of these Diptera are plant pollinators. And some (for example, ktyrs 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 in the forest 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 intestines 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, eggshelminths and even mites. Stingers 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 it completely unfit for consumption, and simply look unaesthetic in borscht. So always separate the flies from the patties - it's good for your he alth!
And some flies are bred
Fly larvae are an excellent source of protein for food 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 VDNKh exhibition. The author of the development is Igor Istomin, head of the New Technologies company.
The project of his farm to breed fly larvae and produce environmentally friendly and highly effective biofeed 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.
The Fly Farm is an example of waste-free and environmentally friendly production at an agricultural enterprise, when all waste is recycled and returned in the form of bio-additives to animal feed and organic fertilizers.
