Blowflies

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Blowflies
Blue blowfly (Calliphora vicina)

Blue blowfly ( Calliphora vicina )

Systematics
Class : Insects (Insecta)
Order : Fly (Diptera)
Subordination : Flies (Brachycera)
Partial order : Muscomorpha
Superfamily : Oestroidea
Family : Blowflies
Scientific name
Calliphoridae
Brauer & Bergenstamm , 1889
Subfamilies
  • Aphyssurinae
  • Auchmeromyiinae
  • Calliphorinae
  • Chrysomyinae
  • Helicoboscinae
  • Melanomyinae
  • Mesembrinellinae
  • Phumosinae
  • Rhiniinae
  • Toxotarsinae

The blowflies (Calliphoridae) are a family of the flies (Brachycera) within the two-winged (Diptera). Around 1,000 blowfly species are known worldwide, around 45 of them in Germany. The size of the animals varies greatly and can be up to eighteen millimeters in the death fly ( Cynomyia mortuorum ).

The name blowfly describes the predilection of these insects for odor-intensive organic substances. In Old High German , tossing means to smear, spread, sully.

The compact body of these flies is usually metallic blue or green to gold-green shiny in color. Eyes and wings are very well developed, as mouth parts they have a lick trunk.

Way of life

Blowflies on fresh chicken droppings

The blowflies are mainly found on flowers, mostly on umbels . They can be found in almost all biotopes . They feed on nectar and pollen and also on honeydew , whereby the taste organs can be found on the limbs of the feet, as with many flies. To take in juices, the flies often look for decayed organic matter and fly to flowers that smell of carrion (such as the arum ) or mushrooms (such as the stinkhorn ( Phallus impudicus )). The scent phenylacetaldehyde causes the attraction of the stinkhorn. The flies eat the mushroom's slime, which also contains its indigestible spores , and thus also ensure that the mushrooms spread.

In some species ( e.g. Protophormia terraenovae ), the males recognize their partner by feeling the females with their feet and probably recognized by the odor sensors . If the female is not willing to mate, it repels the male by vibrating its wings.

development

The clutches, which contain up to several hundred eggs, are deposited on organic, mostly protein-rich substances. In egg-laying problems, however, egg development can be so advanced that the larvae (maggots) hatch during or shortly after the egg is laid. It is attracted by odorous substances that arise during the decomposition and bacterial breakdown of protein , such as ethyl mercaptan , indole , skatole , ammonium carbonate and various amines . These substances are perceived by specific olfactory organs on the antennae of the flies, whereby different species are attracted by different smells. Ethyl mercaptan has a very strong effect on species of the genus Lucilia , but hardly on Calliphora species. The right mixture of odorous substances is also important, whereby individual odor factors can be attractive depending on the concentration and repulsive at other times. For this reason, different types of blowflies arrive at decaying bodies at different times and lay their eggs. This behavior is used, for example, in forensic entomology to determine the time of death and the length of time corpses have been lying there.

In the first stages the larvae breathe through the skin, from the third stage onwards the foremost and rearmost spiracles of the tracheal system open . In their body shape, they represent the classic headless maggots . Blowfly maggots live in and on plant and animal substances that are decomposing. This also includes corpses ( necrophagy ) and excrement ( coprophagia ). In some species, the digestion of food takes place outside the body ( exogenous digestion) by mixing it with their digestive juices and then ingesting the digested food pulp.

In addition to these species, blowflies also include those that occur as external or internal parasites in various vertebrates , including humans. These either live in open wounds or under the skin ( myiasis ) of the hosts. This group includes representatives of the genera Cordylobia (e.g. the Tumbu fly ), Lucilia and Phormia , whereby the larvae of Lucilia sericata are used as a means of wound healing, as they very specifically eat necrotic tissue and in this way keep the wound clean. The pupation of blowflies usually takes place on or in the ground, but pupae of some species can also be found in the nests of the host animals or in the dead host.

Harmful effect

The metabolic products of blowfly larvae are not healthy for the human organism, and meat that has been infected by them is no longer suitable for human consumption. When they visit the food, they also transmit microorganisms that break down protein , carbohydrates and fats. This vector power makes them dangerous pests of meat, fish and dairy products for humans.

Blowflies as a disease vector

Just like some other flies, blowflies are also potential carriers of pathogenic germs and can thus transmit diseases to animals and humans.

Genera of blowflies

Genus Calliphora - Blue Blowflies

The species of this genus are the best known representatives of blowflies in Germany. There are five species from this genus, including C. vomitoria and C. vicina . They reach heights of 11 to 14 mm. Eggs are usually laid on cadavers , but also in many other protein-rich substrates; they are therefore also referred to as blue meat flies . They also occasionally appear on wounds in animals and humans.

Genus Cochliomyia

New World screwworm fly ( Cochliomyia hominivorax )

Genus Lucilia - Goldflies

Nine species of these metallic gold-green to blue shiny flies live in Germany. They can often be found on flowers , rotting materials and stink morels . The eggs are laid on rotting materials, sometimes on the skin of vertebrates or on wounds .

For example, the golden toad fly ( Lucilia bufonivora ) lays its eggs on the dorsal skin of living amphibians , especially those of toads . The larvae migrate in via the nostrils and then begin to eat away at first the soft parts of the head and later the entire body of their host (compare: common toad ).

The species Lucilia sericata lays its eggs regionally on sheep , especially in the shoulder, back and hind legs. The larvae penetrate the skin and migrate through the connective tissue, eating. If nothing is done about it, the sheep will become paralyzed by excreted toxins and death will occur. Occasionally they also live in wounds of other vertebrates, including humans , and feed on dead tissue there. Germ -free maggots grown in laboratories can therefore also be used in human medicine for maggot therapy .

Genus Melinda

In these flies, such as M. caerulea , the eggs are deposited individually or in groups of three at most in the mantle cavity of various snails . The larvae are parasitoids in the snails, which means that they eat the snails and grow in the process. The host dies shortly before pupation.

Genus Protocalliphora - avian blood flies

Three species of blood flies live in Germany, such as P. falcozi . The larvae of these flies live in bird nests and especially draw blood from the young birds. The larvae of some species live under the skin of the host animals, for which the infestation can sometimes be fatal.

Systematics

There are over 100 species in Europe:

gallery

  • Calliphora vicina

  • New World screwworm fly ( Cochliomyia hominivorax )

  • Goldfly - genus Lucilia

literature

  • Joachim Haupt, Hiroko Haupt: Flies and mosquitoes - observation, way of life. Naturbuch, Augsburg 1998, ISBN 3-89440-278-4 .
  • Klaus Honomichl, Heiko Bellmann: Biology and ecology of insects. CD-Rom, Fischer, Stuttgart / Jena / New York 1996, ISBN 3-437-25020-5 .
  • Klaus Honomichl, Werner Jacobs: Biology and ecology of insects: a pocket dictionary. 3rd edition, Fischer, Stuttgart / Jena / Lübeck / Ulm 1998, ISBN 3-437-25890-7 .
  • Bernd Karger (edit.): Handbook of forensic medicine. Volume 1, Chapter 2.2.7, Springer, Berlin 2004, ISBN 3-540-00259-6 , pp. 170-187.

Web links

Commons : Blowflies  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Kurt Maria Zrenner, Rolf Haffner: Textbook for meat inspectors. Thieme, Stuttgart 1999, ISBN 3-432-29531-6 , p. 316 f., Limited preview in the Google book search
  2. ↑ Calliphoridae in Fauna Europaea. Retrieved July 19, 2011