Megalyridae

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Megalyridae
Systematics
Class : Insects (Insecta)
Order : Hymenoptera (Hymenoptera)
Subordination : Waist Wasps (Apocrita)
Superfamily : Megalyroidea
Family : Megalyridae
Scientific name of the  superfamily
Megalyroidea
Schletterer, 1889
Scientific name of the  family
Megalyridae
Schletterer , 1889

The Megalyridae are a family of hymenoptera (Hymenoptera), they belong there to the more original waist wasps with a parasitoid way of life (" Legimmen ", Terebrantia or Parasitica). The family includes about 50 recent species that live worldwide in the tropics and the temperate latitudes of the southern hemisphere, one species north to Japan.

The name derives from the extremely long ovipositor of the species of the Australian genus Megalyra ("long tail" from ancient Greek megal-yra, actually: -ura), which is why the Megalyridae are sometimes referred to as "long tailed wasps" in English.

features

The Megalyridae are small to medium-sized, stocky-looking waist wasps (with a wasp waist ). The head has large complex eyes and relatively long, thread-like antennae , which in both sexes consist of 14 limbs. Characteristic of the family is the antenna pit, a depression in the head capsule downwards into which the antennas can be inserted and which is limited at the top by a keel. Such a pit also occurs in other families, e.g. B. in the Orussidae . The mandibles are built symmetrically and almost always have three teeth. On the trunk, the front section (the prothorax ) is always short and barely visible from above. The position of the anterior (mesothoracic) pair of stigmas is peculiar ; it is always shifted forward and seems to lie completely in the pronotum . The rear part of the trunk ( metasoma ) is always well developed and very broad. The wings are clear, the forewings often have dark spots or bands. A wing mark ( pterostigma ) is not recognizable in the fore wing. The veining of the small hind wings is greatly reduced and mostly apparently only consists of a single longitudinal artery with a small hook. Other features relate to the internal anatomy (e.g. muscles and their attachment points) and are not visible from the outside. A special feature of the genus Megalyra is the female's long, thin ovipositor, which protrudes backwards. In some species it can reach eight times the body length, which should also be a record within the "legumes", which often have long oviposers. The Australian species Megalyra shuckardi has z. B. with a body length of 22 mm an ovipositor of 82 mm (so a total of about 10 centimeters in length). The laying drill is flexible and bendable, it is inserted more like a probe into wood drill holes or cavities than actually used to drill through wood. The length of the ovipositor, however, is not a family feature; there are genera with a very short ovipositor. The absolute body size or ovipositor length is not a feature either, the variability within the species is very great, with the females almost always being significantly larger than the males.

Way of life

The larvae of the Megalyridae are parasitoids of insect larvae. In almost all known cases, they parasitize beetle larvae, mostly those from families living in wood. Only one Australian species ( Megalyra troglodytes ) is known to have parasitized the grave wasp larvae (Sphecidae), which create clay nests on rock faces. The biology of most species outside of Australia, however, is virtually unknown. The larvae are immobilized by the females with a sting and then an egg is laid on them. The hatching larva feeds on the host larva from the outside (ectoparasitoid or idiobiont).

distribution

Megalyridae are animals of the tropics, they occur in temperate latitudes almost only in the southern hemisphere. They are widespread in South America (three genera, two of them in Chile), in Africa (two genera) in Central to South Africa, especially many species in Madagascar (most of them not yet scientifically described). One species is said to have been introduced from Australia to South Africa (presumably in eucalyptus wood). Three genera live in tropical East Asia, one of which ( Carminator ) is distributed northwards to the Japanese main island of Honshū , further occurrences in the northern hemisphere are unknown. One of the genera ( Megalyra ) with numerous species lives in temperate Australia .

Systematics

The family is relatively isolated among the hymenoptera and is the only one in the monotypical superfamily Megalyroidea. Traditionally, they are placed in a family group including the superfamilies Ceraphronoidea , Trigonaloidea and Evanioidea , which has been described as "Evaniomorpha". In more recent analyzes including molecular methods (comparison of homologous gene sequences) this grouping could not be confirmed in this form. Nevertheless, either the Trigonaloidea (with the only family Trigonalidae ) or the Ceraphronoidea are the most likely sister groups .

The following (recent) genera are recognized within the family:

Fossil record

Fossils of the family have been around since the Lower Cretaceous . In almost all cases it is a question of inclusions in amber , the assignment of the few compression fossils in limestone is controversial and possibly belong to other families. Curiously, all of the relatively numerous fossil finds come from the northern hemisphere. The family was obviously spread around the world earlier.

Individual evidence

  1. ↑ Simon van Noort & Scott Shaw (2009): Megalyridia capensis (Hymenoptera: Megalyridae: Megalyridiini), a relict species endemic to South Africa. African Natural History 5: 1-8.
  2. ↑ Michael J. Sharkey, James M. Carpenter, Lars Vilhelmsen, John Heraty, Johan Liljeblad, Ashley PG Dowling, Susanne Schulmeister, Debra Murray, Andrew R. Deans, Fredrik Ronquist, Lars Krogmann, Ward C. Wheeler (2012): Phylogenetic relationships among superfamilies of Hymenoptera. Cladistics 28: pp. 80-112. doi : 10.1111 / j.1096-0031.2011.00366.x
  3. ↑ Vincent Perrichot (2009): Long-Tailed Wasps (Hymenoptera: Megalyridae) from Cretaceous and Paleogene European amber. Paleontological Contributions 1: pp. 1-35.

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