Spheciformes

Grave wasp Ectemnius lapidarius

The grave wasps ( Spheciformes ) are Hymenoptera from the partial order of Stechimmen. They are very closely related with the bees, but this relationship is not apparent at first glance, but was only discovered in 1872 by applying the Darwinian theory of evolution. Similarities, the grave wasps and bees are distinguished from the other Stechimmen lie in the construction of the thorax: the pronotum, which is the back part of the ( narrow ) first thoracic segment, is in its rear corners typical thickening and does not reach the wing scales that cover the wing joint.

Features

The grave wasps live separately (only from the tropical genus Microstigmus, as well as a few non-European species of the genera Arpactophilus and Spilomena are eusoziale species known) and have powerful jaws that are suited by strongly developed upper jaw to the ditch.

The grave wasps are a very diverse group: The size ranges from two millimeters to several centimeters, many species are shown in yellow in varying degrees, some have a red abdomen basis. Many species have developed a stalked abdomen, that is, the first abdominal segment is as long, thin stalk ( petiole ). Worldwide nearly 10,000 species have been described from Central Europe are 300 of them known. Among the grave wasps include the Common Sand Wasp Wasp roundabout and the bee wolf.

Way of life

While feeding the adult animals of nectar and pollen, the larvae of the grave wasps are supplied by the females depending on the type of insects, insect larvae or spiders. The females paralyze their prey with a sting. The prey is carried cavities as host or food supply for the larvae in self-dug (or in brick ) and each filled with an egg. Some grave wasps live in Halmfliegen caused by bile pricked plants.

In evolutionary considers the sometimes very complex brood care behavior ( more nests / multiphase brood care of some grave wasp species ) must be created on certain intermediate steps. As a starting point, the Rezentbeispiel some parasitic wasps can be cited, put the egg on or in the prey, but let this otherwise undisturbed. A continuation of this behavior show some dagger wasps, which paralyze the prey with a bite, but in its place (which is usually quite hidden ) left. The next advanced behavior show some Wegwespen that actively hide the paralyzed prey. The grave wasps eventually create first a special room for the prey; then only done hunting. This behavior allows (in consultation with the size of the prey ) charging more prey organisms in a hiding place. In such a hiding place several brood cells, the ( labor-saving ) can branch off from a single supply duct were created, as in the case of locusts sand wasp ( Sphex funerarius ).

Dean Wooldridge describes in his work Mechanical Man: The Physical Basis of Intelligent Life (1968), that the grave wasp Sphex ichneumoneus the prey settles next to the entrance of the hiding place after a successful hunt, and then inspect the hiding place and then place the prey animal in it and the to lay egg. An observer moving the prey only a few centimeters, so the grave wasp the prey animal shall, after leaving the hideout first back to the previous room to again inspect the hideout. These behavioral stereotypy of Sphex has been Jean Henri Fabre described exactly. It can be any cause often without at the grave wasp a learning effect or dulling one devices. In his book, Douglas R. Hofstadter Metamagicum gives this example to ( partially translated Sphexität ) to develop the concept " sphexishness ", which he then used to explain the self-reflection.

System

It found, first in a superfamily " Sphecoidea " the grave wasps ( Sphecidae ) and the bees ( Apidae ) as sister groups over (or two superfamilies Sphecoidea and Apoidea ). With the principles of cladistics but changed the perspective. The grave wasps were found to be paraphyletic group and split into four families, which together with the family of bees ( Apidae broader sense ) are summarized to the superfamily Apoidea. The different way of life of the bees that feed their larvae with pollen, and the corresponding adaptations are derived morphology characteristics that grave wasps in their entirety are distinguished only by the absence of these features. The Spheciformes include the following groups:

  • Heterogynaidae
  • Ampulicidae Subfamily Ampulicinae
  • Subfamily Dolichurinae
  • Subfamily Ammophilinae
  • Subfamily Chloriontinae
  • Subfamily Sceliphrinae
  • Subfamily Sphecinae

Fossil evidence

The oldest fossil evidence of this group are known from Baltic amber ( Eocene ). Among these are mainly representatives of the family Crabronidae. The diversity of species in Baltic amber indicates, however, indicates a much earlier origin of this group. Cretaceous finds of North America are not taxonomically unique to you.

Trivia

The grave wasp species Polemistus chewbacca and Polemistus vaderi been designated by Menke and Vincent in 1983 after Star Wars characters.

Charles Darwin Mandible (insect mouthpart) European beewolf Scoliidae
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