Larra (genus)
Larra is a genus of wasps grave ( Spheciformes ) from the family Crabronidae. Worldwide 62 species are known, their main distribution area are the tropics. In the Palearctic occur in three ways, one of which, Larra anathema, is also common in Europe. The genus is considered within the grave wasps as basal, it has many original features.
Features
The grave wasps of the genus Larra are 6-25 mm long. They have a black base color, most species show a red coloration on the gaster. For species of the subgenus Cratolarra, which are distributed mainly in Asia, and the legs are at least partly red. In the subgenus Larra the legs are black. The gaster and propodeum are shiny, head and chest are dotted fine or coarser.
The legs are, especially in females, is relatively short. Some features may be used only in the females to distinguish it from other genres. These include the legs, especially the shape of the last Tarsenglieder. The Tarsenklauen are short and not serrated. The last Tarsenglied widens gradually towards the end and is not shovel-shaped with parallel edges constructed as in the closely related species Liris. Seen from the side, this Tarsenglied is only weakly curved and not as dense with short bristles occupied on the bottom as with Liris. In Liris these features are absent in Larra could be adaptations for digging the tubes for the brood cells. The mandibles are not serrated as in other genera in which the dentition is probably an adaptation for the transport of the prey, which is attributable to the genus Larra.
These features are formed fairly uniform in all species of the genus Larra, some of them can be found, however, also in other genera. However, the principal distinctive feature of the genus Larra to other genera is their way of life.
Way of life
The brood is supplied with mole crickets ( Gryllotalpidae ). For this reason, attempts have been made for biological pest control with these grave wasps, about to fight the entrained in Hawaii or Puerto Rico mole crickets. The females do not build their own nests, but use the canal system of the mole crickets. The crickets are detected from the surface, the female then penetrates into their nest. The cricket flees mostly to the surface, where it will eventually weak stunned by a stitch and topped with an egg. Remains the cricket in its construction, it is made into the open by the wasp after stunning. Overall, a female take about 30 very small eggs in their lifetime. This usually takes place between the legs on the ventral side of the thorax of the prey. The paralysis of the cricket usually lasts only a few minutes, she buries herself in the connection back to their nest. When they molt randomly shortly after oviposition, perish the grave wasps nesting. This type of parental care is considered to be very original. There must be a greater number of eggs are stored as in the closely related genus Liris, their own nests built and each brood cell supplied with several crickets in order to achieve the same breeding success.
System
The type species for the genus Larra Larra is ichneumoniformis Fabricius, 1793, originally described by Rossi, 1790, under the name of Sphex anathema. Therefore, this type is called Larra anathema today. Larra is the nominate of the tribe Larrini and the subtribe Larrina within the subfamily Crabroninae. Larra is in the subgenera Larra ( Cratolarra ), whose species were formerly often made to Liris, and Larra ( Larra ), with more primitive features, divided.