Gall mosquitoes

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Gall mosquitoes
Cut bile with larva of the beech gall mosquito Mikiola fagi

Cut bile
with larva of the beech gall mosquito Mikiola fagi

Systematics
Order : Fly (Diptera)
Subordination : Mosquitoes (Nematocera)
Partial order : Bibionomorpha
Superfamily : Sciaroidea
Family : Gall mosquitoes
Scientific name
Cecidomyiidae
Newman , 1834

The gall midges ( Cecidomyiidae) are a family of midges (Nematocera). They occur worldwide with approx. 6000 kinds in more than 530 genera . There are more than 270 genera in Europe .

features

The mosquitoes reach a body length of 0.5 to 4 millimeters, a few species are up to 8 millimeters long. Their body is usually yellow-orange, ocher, light or dark red to almost black in color. With a slim body and long legs, they have the normal build of mosquitoes. Their thread-like antennae have two basic links and a further 4 to 30 links. Most species have 14 to 16 antennae. They are often covered with hair arranged like a whorl. The wing veins of the broad and partly hairy wings are greatly reduced. In addition to their compound eyes , which are connected to one another via the antennae, some species also have point eyes ( Ocelli ). Some of the females have a very long, telescopically retractable laying tube ( ovipositor ).

The maggot-like, spindle-shaped and legless larvae are about two to five millimeters long and are usually light yellow, orange-red, sometimes dark brown and have a reduced head capsule. The third instar larvae have a thickened skin on the abdomen called the thoracic bone or spatula sternalis. In the second larval stage, this thickening can only be partially recognized.

Way of life

Gall mosquitoes spend most of their lives in the larval stage. The fully developed adults only live a short time and hardly eat any food.

The larvae of almost all species live monophagous on only one type of plant or oligophagous on plants of a certain genus. Their food spectrum ranges from grasses and other herbaceous plants to conifers and deciduous trees . Only a few species feed on polyphagous species , but there are also saprophagous species, which presumably feed on fungal hyphae , and parasitic and predatory larvae. The latter are sometimes also used for biological pest control, such as. B. Aphidoletes aphidimyza . They mainly eat spider mites and aphids .

The herbivorous species almost always form galls , which is where the mosquitoes get their name from. The larvae of the non-gall-forming species usually live freely on plants. They attack all parts of the plant except the roots. They can jump by bending their body in a ring like a spring. Many species are important pests in agriculture and forestry (see species list).

The pupation takes place in a mummy doll instead, which is usually yellowish or reddish and tubular protruding Stigmenöffnungen has.

Some types, such as B. those of the genera Miastor and Heteropeza , can reproduce by means of pedogenesis , a special case of parthenogenesis (virgin generation). Most of the time, these species only exist as female larvae and are able to reproduce in the larval stage. Female larvae emerge again from their unfertilized eggs. Winged adults of both sexes, which reproduce sexually, only seldom or under special conditions arise in these species.

genetics

A peculiarity in the genetics of the gall mosquito is that the males only pass on those genetic traits to their offspring that they themselves received from their mother. This is based on a special form of reduction division in spermatogenesis : The normally occurring pairing of homologous chromosomes does not take place here, and only the chromosomes of maternal origin connect to the nuclear division spindle . The subsequent cell division is highly inequitable, ie the two daughter cells are of different sizes. Only from the smaller daughter cell, which received the maternal chromosomes, do two sperm cells emerge. The consequence of this elimination of the paternal genetic makeup is that continuous lines of inheritance only exist in the female sex and the males only act as mediators between these lines. The pedogenesis described above in some gall flies represents a further reduction in the role of the male sex.

Also unusual is the presence of numerous additional chromosomes, which are only present in the cells of the germ line of the gall mosquito and are eliminated when the first somatic cells arise because they remain in the equatorial plate during mitosis , i.e. are not taken up in either of the two daughter nuclei. For a long time, the greatly increased number of chromosomes in the germline was interpreted as polyploidy , ie as an increase in the normal (somatic) number of chromosomes, until it turned out that these were special chromosomes that were different from the somatic ones.

Systematics

Subfamilies

The gall midges are currently divided into six subfamilies. The largest subfamily are the Cecidomyiinae, whose larvae develop in plant galls. They are therefore of great importance for agriculture, forestry and horticulture. There are currently around 4800 species of this subfamily described. The representatives of the other subfamilies do not live in Gallen. Like most species of the mushroom mosquito superfamily, they feed on mushrooms and comprise a total of around 1200 species. The substrate in which the species of the subfamilies Catotrichinae, Lestremiinae and Micromyinae find their food is dead, rotting wood. Therefore these three groups, which until some time ago were all united in the subfamily Lestremiinae, are called wood midges. The Porricondylinae subfamily does not form a uniform family group, and its phylogenetic composition is the subject of new molecular genetic research.

  • Cecidomyiinae - gall midges in the narrower sense
  • Catotrichinae - wood mosquitoes that were spun off from the Lestremiinae
  • Lestremiinae - wood mosquitoes in the narrower sense
  • Micromyinae - wood mosquitoes that were spun off from the Lestremiinae
  • Porricondylinae - the group is not monophyletic and is currently split into other groups

Types (selection)

Fossil evidence

The probably oldest fossil evidence of this family of insects was found in Lebanon amber ( Lower Cretaceous , approx. 120 million years old). Further, somewhat more recent Cretaceous evidence comes from Siberian amber and amber finds that were made in France. The family is rich in species in the Eocene Baltic amber , and also in the mostly somewhat younger Dominican amber .

Individual evidence

  1. ↑ a b Gall mosquitoes (Diptera, Sciaroidea: Cecidomyiidae). Research projects Diptera, Senckenberg German Entomological Institute Müncheberg (SDEI), accessed on February 13, 2016
  2. ↑ Cecidomyiidae. Fauna Europaea, accessed December 24, 2009 .
  3. ↑ a b J.J. Stuart, JH Hatchett: Cytogenetics of the Hessian fly: II. Inheritance and behavior of somatic and germ-line-limited chromosomes , Journal of Heredity 79 , 190-199 (1988) ( abstract )
  4. ↑ D. Schlee and H.-G.Dietrich: Insect -guiding amber from the Lower Cretaceous of Lebanon . In the New Yearbook Geol. Paleont. Monthshefte , pp. 40–50, Stuttgart 1970, cited in Poinar 1992
  5. ↑ George O. Poinar, Jr .: Life in Amber . 350 pp., 147 figs., 10 plates, Stanford University Press, Stanford (Cal.) 1992. ISBN 0-8047-2001-0
  6. ↑ George O. Poinar, Jr. & Roberta Poinar: The Amberforest . 239 pp., Princeton 1999. ISBN 0691028885

literature

  • W. Westerheide and R. Rieger: Special Zoology. Part 1, unicellular organisms and invertebrates. Spectrum Academic Publishing House: Heidelberg, Berlin 2004.

Web links

Commons : Gall Mosquitos  - Collection of images, videos and audio files