Petite field wasp
| Petite field wasp | ||||||||||||
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Preparation of a female |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Polistes bischoffi | ||||||||||||
| ( Weyrauch , 1937) |
The petite field wasp ( Polistes bischoffi ) is a hymenoptera from the family of the wasps (Vespidae). It was only in 2014 that Polistes helveticus was split off from her as an independent species after differences had been recognized and an examination of body features and mtDNA confirmed that a second species had to be split off. The new description of Polistes helveticus led to the fact that most of the specimens designated as Polistes bischoffi , especially in Central Europe, correctly concern Polistes helveticus . It was found that around 450 specimens were incorrectly labeled in Switzerland and that only fewer than 10 genuine Polistes bischoffi specimens could be found in collections until the new species was first described . In southern Europe this is the other way around.
features
The animals have a body length of up to 14 millimeters (queen). Like the rest of the field wasps, they are shown in black and yellow. The species is very similar to the female mountain field wasp ( Polistes biglumis ). Polistes helveticus is also similar . It is one of the smallest Polistes species in Europe. The small and moderately light colored wasps have antennae in which the second antennae pedicellus and only the outermost base of the first flagellomer are always black on the upper side. The flagellum is otherwise light yellow or slightly darkened above in both sexes. This distinguishes the species from Polistes helveticus , which was only split off from Polistes bischoffi as an independent species in 2014 . Polistes helveticus and P. bischoffi are the only two European Polistes species that often lack the epicnemial suture in females. Since these two species are easily distinguishable due to their different coloring (especially the antennae), confusion with other Polistes species is hardly possible.
The female can be identified as follows: it has a regressed or missing epicnemial suture, its hypopygium is black. The hips ( coxes ) of the hind legs are usually just as black, but they can rarely be spotted yellow on the upper side. The mesoscutum is usually black too, it rarely has a fine pair of yellow dots. The propodeum usually has a yellow spot on the side. The male can be recognized by the yellow epicnemium and mesosternum as well as the cheeks, which, viewed from the dorsal side , taper directly behind the compound eyes .
Description of the females
The females are 9.9 to 14.1 millimeters long with a fore wing length of 7.8 to 11.4 millimeters. Their frontal plate ( clypeus ) is yellow with a black border and a large black spot in the middle, which is usually isolated, but is rarely designed as a rhombus-shaped cross band and then reaches the side edge. The face has a large, almost triangular yellow spot that reaches the inner edge of the compound eyes. The upper part of the cheeks bears a small elongated spot, the frons bears a usually uninterrupted horizontal yellow stripe. On the mesosoma , the surface texture changes from coarse on the mesepisternum to smooth on the epicnemium, often evenly. The pronotum has a pair of longitudinal stripes on the rear edge that do not reach the transverse stripe on the collar of the pronotum. The scutellum bears a pair of yellow, somewhat triangular spots, followed by a pair of rectangular spots on the metanotum and a pair of crescent-shaped spots on the back of the propodeum . The mesopleuron has a yellow spot. The propodeum is yellow on the sides. The tegulae are yellow in front and behind and have a rather transparent area in between. The legs are apically yellow and orange; They are black only on the hips (coxes), the thigh ring ( trochanter ) and large parts of the thighs ( femora ), including the base of the thighs.
On the metasoma, each tergum has a continuous yellow band at the rear, which is however slightly notched in black. There are also two yellow spots on the second tergum; only rarely are there two small yellow spots on the first tergum. On the second and third sternum the yellow band is usually continuous on the posterior margin, on the third sternum it is occasionally notched in the middle near the interruption. The bandage on the fourth sternum is interrupted, on the fifth the bandage is clearly interrupted and only developed as yellow spots on the side.
Description of the males
The males are 11.3 to 13.4 millimeters long with a fore wing length of 9.3 to 9.8 millimeters. Their mandibles, the area from their base to the bottom of the compound eyes, the forehead plate, an elongated spot on the upper side of the cheeks, and the face are colored yellow. The upper part of the frons, the vertex, parting and the back of the head are black. The front plate is apically rounded and has a fine groove on each side that extends to the orbital indentations.
On the mesosoma, the pronotum is yellow and has a transverse stripe along the collar that often extends down to a pair of longitudinal yellow spots on the lateral margin of the pronotum. The epicnemium and mesosternum are yellow. The legs are yellow and partially orange, except for the top of the hips, thigh rings, and thighs, which are black. The rest of the mesosoma is colored like that of the females.
On the metasoma, the yellow band at the back of the second tergum extends laterally to the base, but is partially interrupted. The other terga are colored like the females. The second sternum has a pair of mostly isolated yellow spots. The third sternum has yellow bands on both the posterior and anterior margins. The fourth and fifth sternum have a continuous yellow band at the back; it is interrupted on the sixth sternum and absent on the hypopygium .
Occurrence
In comparison to Polistes helveticus, Polistes bischoffi is the species that occurs in the south. The "new" distribution of Polistes bischoffi has only covered southern Europe since the split and extends from the Atlantic coast of southern France via Turkey to western Asia. Its northernmost known occurrence is the Austrian area of the Pannonian Plain near Neusiedl am See , as well as several sites in Switzerland, where the species was found in 1927 on the Versoix river near Geneva . The species occurs sympatric with Polistes helveticus at all of the more northerly localities in Switzerland, i.e. they colonize the same habitats. There are no finds there before 1992, which suggests a spread due to global warming.
In Switzerland, the species, even more so than Polistes helveticus , is bound exclusively to moist habitats such as swamps on lake shores. They can be found in Switzerland from sea level to around 540 meters above sea level, with finds in Turkey from significantly higher altitudes, for which, however, an exact altitude is no longer known.
Way of life
The nest is also built in syntopically populated habitats similar to Polistes helveticus close to the ground on plant stems or trunks. The honeycombs reach a maximum diameter of five millimeters; only about 30 workers live in a nest. Most of the animals were found in August and September. The earliest evidence of a female from April 19 comes from Galéria (Corsica), the latest of an active nest from September 10 from Mönchaltorf (Switzerland). The earliest documented male was caught in Pfäffikon (Switzerland) on August 10, and the latest in Wetzikon (Switzerland) on September 9. The petite field wasp is aggressive and can sting people painfully, although the pain does not last long.
supporting documents
Individual evidence
- ↑ a b c d e f g h i j k l m Rainer Neumeyer, Hannes Baur, Gaston-Denis Guex & Christophe Praz: A new species of the paper wasp genus Polistes (Hymenoptera, Vespidae, Polistinae) in Europe revealed by morphometrics and molecular analyzes. ZooKeys 400: 67-118, doi : 10.3897 / zookeys.400.6611 .
- ↑ a b c d Rolf Witt: Observe wasps, determine . 1st edition. Naturbuch-Verlag, 1998, ISBN 3-89440-243-1 , p. 170 .
literature
- Rolf Witt: Observe wasps, determine . 1st edition. Naturbuch-Verlag, 1998, ISBN 3-89440-243-1 .