Morphology of Beetle Head and Mandible

Overview

Although male Priacma Serrata are easily collected, available data on internal morphology and biology are restricted to very few representatives. The use of X-ray microtomography (XMT) presented itself as a valuable technique for the investigation of insect structures. An important advantage of XMT over other methods is the possibility of a non-destructive investigation of internal structures.

Characteristics:

  • Using micro CT to non-destructively investigate insect morphology
  • Create an accurate FE mesh to analyse why the mandible has evolved to that shape
  • Ability to scale up STL mesh for rapid prototyping

Thanks to

J. Bond, University of Exeter
T. Hörnschemeyer, University of Göttingen, Germany

Image Acquisition

The specimens for the X-ray tomography were transferred to 100% ethanol and dried in a Balzer CPD 030 Critical Point Dryer. The dry specimens were mounted with soft wax to the sample stage of the X-ray machine. All measurements and reconstructions were made with a SkyScan 1072 high-resolution Micro-CT system.

Mesh and Model Generation

Slices from the XMT data were imported into ScanIP and a simple flood fill algorithm applied to segment the head structure. The segmented beetle head is about 5 mm long and the mandible measures 1.2 x 2.8 mm. The segmented structure was then meshed using the +FE module and exported to Abaqus® for further analysis. In addition, a scaled up surface mesh (.stl) was exported to produce an RP model of the head and mandible.

Simulation

A mesh of the head and mandible consisting of 70,000 nodes and 250,000 elements (the mandible on its own has 30,000 nodes and 106,000 elements) was imported into Abaqus® were material properties and loads were applied. The results show that the mandible is curved to distribute stress, and it acts as a scoop mechanism.