Wespe im CT-Scan, Foto: Maraike Willsch, Museum für Naturkunde
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Introduction and aims of the project

The dissertation deals with the phylogeny and evolution of Aculeata. Using microCT scans and 3D reconstructions we investigate the skeletal musculature of the thorax in wasps from all over the world. Structural characters are elaborated to develop a broad morphological data set for clarifying phylogenetic relationships. The single structures are/will be freely accessible via the MfN (https://doi.org/10.7479/dft0-yy6m) and the Hymenoptera Anatomy Ontology Portal.

Methods

The extremities and the gaster are cut off the specimens that are stored in alcohol. They are stained with iodine-ethanol and carefully dried (critical point drying). Then, 3D pictures are made with a micro-computer tomography scanner (µCT). All muscles are labelled manually with the 3D software AmiraZIB to enable a turning on and off of single structures. Thus, a muscle can be analysed individually. One half of the thorax is analysed. In comparison with genetic work our results will complement the knowledge about the relationships among and within the taxa.

Interim results

Comparing the specimens our work shows significant differences in number and structure of the musculature. That is explainable with their different way of life. More than 40 muscles can be found in one half of a meso- and metathorax of a wasp.

Publications

  • Willsch M, Friedrich F, Baum D, Ohl M (in prep) Phylogenetic meaning of the multifarious anatomy of the mesosoma in aculeate Hymenoptera (Apoidea and Vespoidea).
  • Graf S, Willsch M, Ohl M (in prep) Comparative morphology of the musculature of the sting apparatus in digger wasps by means of 3D imaging (Hymenoptera: Sphecidae).
  • Jurisch I, Willsch M, Ohl M (in prep) Flightless wasps: The mesosomal musculature of aculeate Hymenoptera (Heterogynaidae, Mutillidae, Tiphiidae).
  • Willsch M, Friedrich F, Baum D, Jurisch I, Ohl M (accepted) A comparative description of the mesosomal musculature in Sphecidae and Ampulicidae (Hymenoptera, Apoidea) using 3D techniques. Deutsche Entomologische Zeitschrift.
  • Willsch M (2019) Micro-computed tomography scanning of the mesosomal musculature in Apoidea (aculeate Hymenoptera) – segmented structures and raw data. [Dataset]. Data Publisher: Museum für Naturkunde Berlin (MfN) – Leibniz Institute for Research on Evolution and Biodiversity. https://doi.org/10.7479/dft0-yy6m

Associated student projects

Two theses were made within this PhD project:

  • Master’s thesis (German): “Die Morphologie des Mesosomas aculeater Hymenopteren mit reduzierten Flügeln“ by Ivo Jurisch, University of Rostock, 2016.
  • Bachelor thesis: Comparative morphology of the sting apparatus in digger wasps by means of µ-computed tomography” by Stefan Graf, Humboldt-Universität zu Berlin, 2017.

Cooperations

  • Zuse Institute Berlin: Provision of the software AmiraZIBEdition
  • Dr Frank Friedrich, University of Hamburg: Software training and contact person for 3D-visualisations and muscle structures
  • Hymenoptera Anatomy Ontology, USA: Portal for public access to morphological data

Project title

The Phylogeny and Evolution of the aculeate Hymenoptera

Funding

Deutsche Forschungsgemeinschaft DFG until 30.09.2017