Blasticotomidae

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Blasticotomidae
Systematics
Class : Insects (Insecta)
Order : Hymenoptera (Hymenoptera)
Subordination : Plant Wasps (Symphyta)
Superfamily : Sawfly (Tenthredinoidea)
Family : Blasticotomidae
Scientific name
Blasticotomidae
Thomson , 1871

The Blasticotomidae are a family of plant wasps tied to fern species. Twelve species are known worldwide.

features

The adults are about 5 to 10 mm long and brown to black in color, often with yellowish legs. The construction of the short antennae is peculiar: it has only three or four links, the third link of which is greatly elongated, the result of the fusion of almost all of the whiplash links. In the genus Blasticotoma there is a tiny fourth limb above it, which the other genera are either completely absent or so reduced in size that it is easily overlooked. Further features in the wing are the stalked and pear-shaped first discoid cell, the large and semicircular wing mark (pterostigma). The forelegs have two apical spines, the inner of which is two-pointed.

Larvae

Foam balls of Blasticotoma filiceti on Athyrium filix-femina

The larva is described in the European species Blasticotoma filiceti . It is greenish-white in color, with a light brown to reddish brown head capsule and in the last stage about 11 mm long. It has five-part antennae. There are three pairs of legs on the thorax , while the abdominal legs are completely absent. Two very long, tapered appendages above (dorsal) on the eighth and ninth abdominal segment are very striking and unmistakable. The larva lives mining in the leaf stem of fern species. In addition to discoloration and the stunting of the subsequent spreading, their presence is usually shown by a foam-like ball of secretion (similar to the foam cicadas ), but which is easily washed off by rain.

Other mining sawfly larvae occur in fern stems (an overview can be found in Jan Macek (2010)), but these have no dorsal appendages.

Way of life

As far as is known, all species of the Blasticotomidae in the larval stage are leaf miners in various fern species. Of the better-known species, several, not necessarily closely related, fern species are recorded. The female drills the eggs one by one or in groups into the stem with her ovipositor. The hatching larva eats a cavity in the stem, which remains very short and hardly exceeds the length of the larva. The actual nutrition takes place via the plant sap escaping in the cavity. This type of nutrition, through liquid food with biting-chewing mouthparts, is extremely unusual in insects. If several larvae occupy a stem, each of them eats in its own cavity, which is completely separate from the others. The flight time of the adults and the laying of eggs is in the European species in the lowlands in May, one to two weeks after the fern fronds sprout (in the Alps at 1400–1600 m at the end of June), the larva about 6 weeks after the adults on the plant verifiable. In both this and the other species, as far as is known, only one generation occurs per year. The Central European species seems to reproduce parthenogenetically, at least in a location where the species could be regularly observed for ten years with five to over 30 adults during the entire flight period, ♂♂ could never be found.

It was only discovered a few years ago that the secretions released by the larva are regularly ingested by ants that form a close bond (trophobiosis) with it, as was unknown in other hymenoptera and until then was almost only detected by plant lice.

distribution

With one exception, all species live in northern East Asia, in China, Korea and Japan, and south to Taiwan. The species Blasticotoma filiceti is distributed all over North Asia and northern Europe, but is only found very rarely, so that almost every find is published immediately. An overview of the European distribution, as far as known, is provided by Wolfgang Schedl (1973).

Only one type of fossil has been found. The Miocene species comes from the fossil deposit of Florissant in North America, where no more recent species of the family occurs and was named Paremphytus ostentatus .

Systematics

The blasticotomidae among the Tenthredinoidea that the Real sawflies include (Tenthredinidae) and some related families. They may be the sister group of all other families. However, this position is not always supported by recent analyzes.

The system within the family is a bit confused. In addition to the genus Blasticotoma, there are one or two other genera. The second genus Runaria was later synonymous with the fossil genus Paremphytus , whereupon the recent species were transferred to this genus. The synonymy was later abolished and the species transferred back, which was not followed by all of the investigators. The third genus Bohea is synonymous with Runaria by some (not all) authors . The result is a confusion in the naming that obscures the situation.

The family system can then look like this:

swell

Individual evidence

  1. ^ Jan Macek: Taxonomy, distribution and biology of selected European Dinax, Strongylogaster and Taxonus species (Hymenoptera: Symphyta). Acta Entomologica Musei Nationalis Pragae, 50, 1, pp. 253-271, 2010
  2. ↑ DE Shcherbakov: Fern sawfly larvae Blasticoma filiceti Klug, 1834 (Hymenoptera: Blasticomidae) visited by ants: a new kind of trophobiosis. Russian entomological journal, 15, 1, pp. 67-72, 2006
  3. ↑ Wolfgang Schedl: First record of the fern leaf wasp Blasticotoma filiceti Klug, 1834 in Austria (Hymenoptera, Blasticotomidae). Journal of the Working Group of Austrian Entomologists, 25, 3/4, pp. 114–117, 1973
  4. ^ Robert B. Benson: Blasticotomidæ in the Miocene of Florissant, Colorado (Hymenoptera Symphyta). Psyche, 49, pp. 47-48, 1942
  5. ^ Susanne Schulmeister, Ward C. Wheeler, James M. Carpenter: Simultaneous analysis of the basal lineages of Hymenoptera (Insecta) using sensitivity analysis. Cladistics, 18, pp. 455-484, 2002
  6. ↑ 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: Phylogenetic relationships among superfamilies of Hymenoptera. Cladistics, 28, pp. 80-112, 2012 doi : 10.1111 / j.1096-0031.2011.00366.x
  7. ↑ TO Zhelochovtzev & AP Rasnitzyn: On some tertiary sawflies (Hymenoptera: Symphyta) from Colorado. Psyche, 79, pp. 315-327, 1972
  8. ↑ Akihiko Shinohara: Discovery of the families Xyelidae, Pamphilidae, Blasticotomidae and Orussidae from Taiwan, with descriptions of four new species (Hymenoptera, Symphyta). Proceedings of the Entomological Society of Washington, 85, 2, pp. 309-320, 1983

literature

  • RB Benson: Handbook for the identification of British insects. Vol IV. Hymenoptera 2. Symphyta Section a. Published by the Royal Entomological Society of London, 1951
  • Nikola-Michael Prpic-Schäper: The fern sawfly of Germany (Insecta: Hymenoptera: Blasticotomidae). Booklets on Germany's animal world, No. 2, pp. 1–12, 2011
  • Andrew D. Liston: Larval behavior of Blasticoma filiceti. Sawfly studygroup newsletter 2, pp. 8-10, 2007
  • David R. Smith: Pars 14, Suborder Symphyta. In: Hymenopterum Catalogus (Nova editio). Dr. W. Junk, BV, The Hague 1978