Oriental wall wasp
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Oriental wall wasp ( Sceliphron curvatum ) |
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| Sceliphron curvatum | ||||||||||||
| ( F. Smith , 1870) |
The oriental wall wasp or mortar wasp ( Sceliphron curvatum ), also called Asiatic clay potty wasp , is a hymenoptera from the family of Sphecidae , which are counted among the digger wasps . The species was originally only known from northern India and Nepal as well as Kazakhstan , but has also spread in Europe since 1979 . She builds characteristic brood cells from clay and other materials.
features
The male of the species reaches a body length of 17 to 20 millimeters, the female 13 to 16 millimeters, making the oriental wall wasp a comparatively large digger wasp. As with all species of the genus, the body is quite slim. It has a narrow and comparatively long petiolus that is just as long as the abdomen or even exceeds its length. The petiolus is mostly straight in this species. In the female, the last tergite is rounded or triangular in shape and provided with a keel. The first tergite has a flat profile when viewed from the dorsal side and appears together with the second from the lateral side in the form of a uniformly curved line. The mesonotum is predominantly dull and its coarse transverse wrinkles are interspersed with numerous points. The basic color of the oriental wall wasp is brown. On the clypeus , the pronotum, the scutellum , the tegulae and the propodeum in front of the petiolus there is a yellow spot on each of the upper mesopleure , two more appear in the same color. The yellow color components can vary depending on the individual and are weaker, especially in males. There are also reddish-brown color components, these take up the majority of the legs and are otherwise also present on the end ligaments on all tergites and sternites. There are lemon-yellow drawing elements on the legs and abdomen. The protruding facial hair is dark.
Similar species
The oriental wall wasp is particularly similar to the closely related species Sceliphron deforme , but differs from it by the yellow spot on the clypeus, which is significantly more expansive in S. deforme , while in the oriental wall wasp this is only limited to the center of the clypeus. Further distinguishing features are the more strongly curved peliotus in S. deforme and partly also the leg color, which can also turn out black in the male of the sister species. From the other species of the genus Sceliphron present in Europe , both species differ in the red-brown leg markings and the red-brown tergite end bands.
Occurrence
The oriental wall wasp was originally distributed from northern India and Nepal to Kazakhstan . However, it was also introduced in south-east, south and central Europe and has successfully established itself there (see chapter Spread in Europe ). The species prefers the proximity of human settlements due to its way of development. One speaks of synanthropy .
Spread in Europe
The species was first found in Europe in Styria in Austria , where the first specimen was sighted in 1979. Since then, the oriental wall wasp has spread to Austria and other countries on the continent. Finds from Slovenia and the western part of Hungary were discovered in 1995 and Croatia in 1996 . In 1997 there were also first sightings of the oriental wall wasp from Serbia and Bulgaria . In Switzerland , it was a find from the canton of Neuchâtel , initially not assigned to the correct species , that indicated the occurrence of the species. The species has been recorded in Italy since 1998, where it occurs particularly in the north and south as far as Emilia Romana and Rome . In 2001 Sceliphron curvatum reached Greece . Since 2002 finds of the oriental wall wasp have occasionally been sighted in Germany . So far, it has been found in the federal states of Baden-Württemberg (here the first find of the species in Germany in Freiburg ), Bavaria , Hesse , North Rhine-Westphalia and Saxony . In the same year there were also records of the species on mainland France and in 2004 more from the French island of Corsica .
The distribution of the oriental wall wasp and other species of the genus has not yet been fully researched. It is also unclear how the species got to Europe. It is believed that this happened through various economic routes or that the larvae reached Europe on transport routes. Another theory would be that the adults found their way to Europe on their own. This is due to the fact that the species first spread in southern and eastern Europe and thus in those parts of the continent that are closest to their original range. A third assumption would be that the adults as such were also dragged along by motor vehicles, as such were increasingly sighted on vehicles that had previously been used in the original distribution area and driven to Europe.
Way of life
The oriental wall wasp likes to live near human settlements. In nature, areas that are particularly protected from rain are used for breeding. The species is predominantly univoltine and can be found at least in Europe from March to August, but mostly between the beginning of June and the end of July, depending on where it is found. As usual with digger wasps and unlike the larvae, the adults do not feed on carnivore , but rather on nectar from flowers.
development
The development of the oriental wall wasp is similar to that of other digger wasps and is divided into several phases. During the winter, the wasps develop through the larval and pupal stages into the spring of the following year.
Making the brood cells
Like all species of the genus, the female makes brood cells in the form of clay pots. In contrast to the other species occurring in Europe, the individual pots are not covered with another layer of clay, but remain exposed as such. First, on the surface on which the clay pots are to be attached, a base made of mostly anthropogenic substances, including Porozell, Bakelite , paper (material from books or wallpaper, for example), and less often brick dust or artificial marble, is created. As the place of origin of the building fabric for the clay pots, the wasp then seeks out suitable locations, including the banks of ponds and persistent puddles on macadam paths , irrigated building sites or the edges of clay pits. Saliva is apparently not added to the building material, which is why a certain amount of moisture in the collected materials is crucial for its suitability as a building material. Collected material is kneaded and shaped both on site and at the construction site of the brood cells and then adapted to the base and applied. A cell consists of nine to fifteen individual lumps of clay. The construction of a single cell can take up to two days, depending on material availability, weather conditions and possible disruptions. The elliptical to pear-shaped clay pots are lined up in a considerably large number (usually 5 to 22, according to observations sometimes also 30 to 85) parallel, or horizontally or vertically, and are usually uniformly shaped in one direction. They are finely structured, especially the later cover. Water can easily dissolve these structures. Therefore, human dwellings, preferably attics of residential buildings or garages and barns, are used, which offer suitable protection against rain and moisture. This also explains the synanthropic way of life. The high number of clay pots is explained by their sensitivity to water. Accordingly, these are made in the wild at suitable water-protected locations. One egg is laid in each cell. With the entire production process, the wasp uses the time between sunrise and just before sunset, and if the weather is suitable, even until dusk.
Spider prey for the offspring
As with all digger wasps , a mated female of the oriental wall wasp hunts live prey for the next generation. Small to medium-sized spiders from various families are preyed on here. The female performs a search flight by flying up and down in a zigzag pattern . If a suitable spider is sighted, the wasp approaches it in a swoop and gives it a paralyzing sting within a few seconds. Was observed in Europe, for example, the successful capture of specimens of horned spider ( Araneus angulatus ), the pumpkin spider ( Araniella cucurbitina ), the green crab spider ( Diaea dorsata ), the autumn spider ( Metellina segmentata ), the columns spider ( Nuctenea umbratica ) and the zebra spider ( Salticus scenicus ). Once paralyzed, the spider is carried into the brood cell in several leaps in flight or in free flight and held by the mandibles and forelegs. The spider's circulation is greatly reduced as a result of the paralyzing poison. As a result, on the one hand, the oxygen consumption of the spider, which is still breathing, is reduced within the later closed cell and, on the other hand, this enables a longer shelf life of the prey intended for consumption by the larva. After stunning, the spider is completely immobile, save for the occasional vibration of the legs. Still, their limbs are very relaxed, allowing more spiders to be introduced into a single cell without complications. The number of spiders hunted can be eight to fifteen per brood cell. As a result, the number of prey animals can be very high in view of the large number of brood cells. The wasp can kill a total of 30 spiders per day. The brood cell that was manufactured last is always provided with spiders first. An egg is placed in a cell provided with sufficient spiders and then closed with a lid. Complete brood cells are repaired within a certain period of time if they are damaged.
Properties of the egg
The egg is very elastic, concave in shape, mostly 3.2 millimeters long and is placed slightly obliquely on the underside between the fan lung stigma and the base of the hip of the opisthosoma by one of the anesthetized spiders and attached to it with a colorless secretion. The egg is mostly designed without structure, but the surface is irregular and rough in the vicinity of both ice tips. Structural reflections can also be seen through the greasy secretion. At the pointed end of the egg you can see a dark, speckled, tiny and blurred spot that may function like a micropyle . The entire egg is covered with two equally elastic egg shells. In observations, the larvae hatched three to five hours after filling up with the prey spiders and at least three hours after the brood cells had been closed.
Development of the larva
The hatched larva goes through three larval stages. As soon as it has hatched from the egg, the inside of the curve of its body lies close to the opisthosoma of the spider on which its egg was laid. With the help of the mouthparts on its head capsule, the larva begins to dig into the body of the spider and begins to suck it up by reaching more and more of the spider's body substance through the digging and then ingesting it by sucking. There is a peristaltic movement throughout the body . On the fourth day the larva has a comma-shaped shape, a body length of about 2.6 millimeters and a whitish to light yellow basic color. Your body consists of several segments, each of which appears to be raised like a bulb. When a spider is eaten, the larva begins to eat the next. The second larval stage is somewhat larger than the first and has more pronounced mouthparts and an adhesive apparatus. However, the basic color remains the same and with the exception of small dots on the body of the larva there are no chitin structures . In the third larval stage, the basic color does not change either, but the head capsule is pale yellow and has two light gray and two other light brown stripes on the forehead. The partly light and dark brown mouthparts are already recognizable as mandibles and appear much more pronounced than in the previous stages. Regarding its size, the larva almost completely fills the brood cell in the third stage. In most cases, the larva eats up all of the spiders within their brood cells and then pupates after sufficient food intake.
Pupation process
The red-brown pupa of the oriental wall wasp hangs in the clay cell on a loose, whitish web. It is provided at the base with a black capsule and white, comma-shaped excretions from the previous larva. The colorations and the cellophane-like lining of the capsule are created by painting over a network-like structure with a waxy secretion that is applied over the entire area. The actual doll has a length of 12 to 18 millimeters and a weight of 0.0164 to 0.2 grams. It is initially white and has colorless extremities. Later, she becomes increasingly reddish brown, which she staining of Imagines comes closer. Brown drawings can also be seen through. The doll consists of an easily fragile retina. The larval skin is attached laterally to the end of the pupa. After successful pupation, which ends in May at the earliest, the imago bites open the lid of the brood cell and leaves it. If some spiders have not been taken in in the larval stage, they will appear in the dried state in the clay cell. If a larva or a pupa does not successfully survive its metamorphosis , it dries up and eventually dies.
Oriental wall wasp and human
In particular, their occasional mass occurrence as a result of their distribution, their considerable size for wasps, and their preferred proximity to human settlements have caused quite a stir in the media and through their reports. Attacks by the wasp on humans have not yet been observed. In one case, a dental practice reported failures of equipment housings and electronic cables due to some brood cells placed in them. Before their occurrence in Europe became known, the characteristic brood cells were sighted several times, but were not recognized as species-specific for the oriental wall wasp.
Systematics
The oriental wall wasp was first described by Frederick Smith as Pelopaeus curvatum in 1870 . It was later assigned to the genus Sceliphron .
Galleries
Stages of development
Different stages of the oriental wall wasp
Oriental wall wasp building a nest
Ready-to-move brood cell
Sealed brood cell
Detail of several brood cells
Detail of some stunned spiders including a wasp egg on a specimen
Another view of a larva
Ventral view of a larva
Open brood cell with several spiders
Ditto, with larva
Broken brood cells
Newly hatched imago and the remains of the pupa capsule
Adults
Copy in the Heilbronn district
Lateral view of the already shown example from Italy
Frontal view of a specimen near the market town of Brunn am Gebirge ( Mödling district , Lower Austria )
Ventral view of the specimen from the Heilbronn district
Oriental wall wasp in Wiesbaden
Wasp in the local community of Platamonas in Greece
Dead find in the French town of Périgueux ( Dordogne department , Nouvelle-Aquitaine region )
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Individual evidence
- ↑ a b c d e f " Sceliphron curvatum (F. Smith 1870) in Europe with an identification key for the European and Mediterranean Sceliphron species (Hymenoptera, Sphecidae)." by Christian Schmidt-Egger, report on the oriental wall wasp and other species of the genus in Europe ( PDF )
- ↑ a b c d e f g h "The Oriental Wall Wasp Sceliphron curvatum (SMITH 1870): Biology and history of spreading in Eastern Austria (Hymenoptera, Sphecida") by Johannes Gepp, report on the way of life and the history of the spreading of the Oriental wall wasp in Austria ( PDF )
- ↑ The Oriental Wall Wasp on the Fauna Europaea website ( Link )
