Pelecinidae
| Pelecinidae | ||||||||||||
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Pelecinus polyturator |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Pelecinidae | ||||||||||||
| Haliday , 1840 |
The Pelecinidae are a family of hymenoptera . The few living species are all placed in the genus Pelecinus Latreille. However, far more fossil species are known than recent ones, so that the surviving family is seen as a relic group of a family that used to be much more species-rich and widespread.
features
They are relatively large hymenoptera with a female body length of 20 to 70 millimeters, which is also variable within the species. The most common species is black, two rarer South American species are partly red-brown. Females are recognizable at first glance and are almost unmistakable within the relationship due to their extremely elongated, long and thin abdomen ( metasoma ) with a short, largely concealed ovipositor. Other important features: The first tarsal link of the hind legs is significantly shorter than the second, in the fore wing the wing vein Rs (radial sector), the only vein branching off from the pterostigma , is forked.
On the head the mandibles are bilobed and overlap at rest, the maxillary palps five, the labial palps three-segmented. The forehead (front) has a triangular elevation in the middle. The antennae are thread-shaped, they insert high above the clypeus , are fourteen segments (the same in both sexes). The point of attachment of the head to the pro notum is narrowed and tied off like a collar. The mesonotum above carries a pair of keel lines, the notaulices, which converge backwards. The mesoscutum and scutellum are separated by a deep, somewhat serrated suture. The propodeum is elongated, smooth on top, densely hairy on the sides. The rear tibia of the female are swollen towards the tip, the front tibia has one, the middle two and the rear also two spurs. The forewings have only two longitudinal veins in the basal half (interpreted as costa and fused subcosta / radius), the costal cell is open to the edge, the wing membrane here is always brownish, apart from this the wings are either clear or, variable and darkened to different degrees ; the wing mark is inconspicuous. The hind wings are completely unveined and darkened towards the edge. In the rest position, the wings are not folded. The metasoma of the female is extremely elongated, it consists of six clearly recognizable segments. The tergum and sternum are clearly recognizable on the first segment, the tergites are fused in a ring shape on the posterior segments, the sternites are divided into two parts and converted into articular surfaces that allow the abdomen to move laterally. On the last segment sit two annexes (Cerci) and a short, largely hidden in the abdomen ovipositor . The metasoma in the male is stalked (first segment elongated), it consists of seven segments, of which only six are externally visible. The abdomen behind the stalk (petiolus) is widened somewhat in the shape of a club, heavily sclerotized, the segments close together.
Way of life
Lifestyle data are only available for the most common species, Pelecinus polyturator . According to this, the larvae are endo- parasitoids of ground-living scarab beetle larvae of the genus Phyllophaga , possibly also of other species with a similar way of life. The female covers the larvae of the third instar with eggs, while the modified, elongated abdomen serves as a tool for digging.
The species is known for the fact that the distribution of the sexes depends on the geographical latitude . Populations in the tropics are bisexual, those in the temperate zones in the north and south consist exclusively of females, they are (thelytok) parthenogenetic .
distribution
The species of the genus live exclusively in America, from eastern Canada over the eastern USA, Central America, the northwest of South America to the Atlantic coast of northern Argentina. In tropical latitudes it seems restricted to mountainous areas and mountains. At least the most common species Pelecinus polyturator is generally considered to be quite common, it is widespread in North America in forests.
Possibility of confusion
The only family with a similar body shape are the Monomachidae . However, these have more longitudinal veins in the forewing, a closed radial cell, veined hind wings, the females gradually (not club-shaped) widened rear rails, and the first segment of the hind tarsi is always longer than the second. (Wingless species only occur in this family).
Systematics, taxonomy, phylogeny
The living genus Pelecinus includes three valid species:
- Pelecinus polyturator in the entire distribution area. Type species of the genus (as Ichneumon polycerator Fabricius)
- Pelecinus dichrous in Argentina, Brazil (Minas Gerais), Paraguay, Uruguay
- Pelecinus thoracicus in Mexico.
The Pelecinidae are a family of the superfamily Proctotrupoidea within the diverse Proctotrupomorpha (formerly often referred to as "microhymenoptera"). This position has also been confirmed in molecular studies (using homologous DNA sequences). They are therefore relatively basal in the superfamily, as the most basal branch after the Roproniidae , possibly also as a sister group to these. This position is considered to be very likely based on both morphological and molecular results. Older results that these two families should be sister groups of gall wasps are now considered unlikely.
Fossils
Fossil Pelecinidae are rare, but have been found in numerous species, so that the fossil family is far more species-rich than recent. 10 genera with more than 40 species have been described. The oldest fossil species come as compression fossils from the central Jurassic Jiulongshan Formation in outer Mongolia (China). Most of the fossil species are smaller than the recent ones. Henopelecinus pygmaeus made of Cretaceous amber from New Jersey (USA) was only 6.5 millimeters long. A species has also been described from the Eocene Baltic amber: Pelecinopteron tubuliforme Brues.
swell
- NF Johnson, L. Musetti: Revision of the proctotrupoid genus Pelecinus Latreille (Hymenoptera: Pelecinidae). In: Journal of Natural History Volume 33, 1999, pp. 1513-1543.
Individual evidence
- ^ Lubomir Masner: Superfamily Proctotrupoidea. In: Henry Goulet, John T. Huber (Ed.): Hymenoptera of the world, an identification key to families. Agriculture Canada. Research Branch. IV Series: Publication. 1993. ISBN 0-660-14933-8
- ^ WRM Mason: Structure and movement of the abdomen of female Pelecinus polyturator (Hymenoptera, Pelecinidae). In: Canadian Entomologist Volume 116, No. 3, 1984, pp. 419-426. doi : 10.4039 / Ent116419-3 .
- ↑ Luciana Musetti, Norman F. Johnson: Revision of the New World species of the genus Monomachus Klug (Hymenoptera: Proctotrupoidea, Monomachidae). In: Canadian Entomologist Volume 136, No. 4, 2004, pp. 501-552. doi : 10.4039 / n03-068 .
- ↑ John Heraty, Fredrik Ronquist, James M. Carpenter, David Hawks, Susanne Schulmeister, Ashley P. Dowling, Debra Murray, James Munro, Ward C. Wheeler, Nathan Schiff, Michael Sharkey: Evolution of the hymenopteran megaradiation. In: Molecular Phylogenetics and Evolution Volume 60, 2011, pp. 73-88. doi : 10.1016 / j.ympev.2011.04.003 .
- ↑ Seraina Klopfstein, Lars Vilhelmsen, John M. Heraty, Michael Sharkey, Fredrik Ronquist: The Hymenopteran tree of life: Evidence from protein-coding genes and objectively aligned ribosomal data. In: PLoS ONE Volume 8, No. 8, 2013, p. E69344. doi : 10.1371 / journal.pone.0069344 .
- ↑ Chungkun Shih, Chenxi Liu, Dong Ren: The earliest fossil record of Pelecinid wasps (Insecta: Hymenoptera: Proctotrupoidea: Pelecinidae) from Inner Mongolia, China. In: Annals of the Entomological Society of America Volume 102, No. 1, 2009, pp. 20-38. doi : 10.1603 / 008.102.0103 .
- ↑ Michael S. Engel & David A. Grimaldi: A diminutive Pelecinid wasp in Cretaceous amber from New Jersey (Hymenoptera: Pelecinidae). In: Northeastern Naturalist Volume 13, No. 2, 2006, pp. 291-297.
