Joint-X

The role of coxa-trochanteral joints in beetle evolution revealed by quantitative synchrotron X-ray microtomography and (semi-)automatic image analysis

Thanks to synchrotron X-ray microtomography, we discovered in 2011 that weevil coxa-trochanteral joints (“hip” joints) closely resemble engineered screw-and-nut systems. Back then, both scanning and data analysis were very time-consuming, effectively impeding a systematic study on a large sample series. As recent progresses in high-throughput X-ray imaging and image analysis now facilitate large-scale digitization on insect 3D morphology, we now have the prerequisites required for a comprehensive study on beetle coxa-trochanteral joint evolution. Within the DFG-funded project Joint-X, we will tackle this challenge by employing state-of-the art synchrotron X-ray microtomography and (semi-)automatic image segmentation.
We will correlate hundreds of morphological 3D datasets to phylogenetic trees, allowing us to identify key events in evolution and trace the transformation from a simple hinge joint into one of the most peculiar morphological characters in beetles – the “biological screw”.
A secondary result of this project will be a comprehensive collection of 3D morphological datasets of beetles, which will be made available to the public via an open online repository. This data can be used by the scientific community to study other morphological characters and to correlate them with other types of data.

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Figure 1. Coxa (A) and trochanter (B) of the weevil Trigonopterus oblongus: partners in a biological screw-and-nut system (scanning electron microscopy).
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Figure 2: Fast data evaluation of a screw joint in 2D and 3D. A: Single 2D slice of the tomographic volume. B: Quick 3D volume rendering of the same dataset. C: Volume rendering from B cut in two planes revealing joint articulation.
Project team at KIT-IPS

Dr. Thomas van de Kamp (principal investigator)
Jenny Hein (PhD student for Joint-X)
Dr. Angelica Cecilia, Dr. Elias Hamann, Dr. Merve Kabukcuoğlu

In collaboration with

Dr. Alexander Riedel (State Museum of Natural History Karlsruhe)
Prof. Dr. Lars Krogmann & Dr. Arnaud Faille (State Museum of Natural History Stuttgart)
Dr. Philipp Lösel (Heidelberg University)
Prof. Dr. Evan Economo & Julian Katzke (Okinawa Institute of Science and Technology)

Funding

Joint-X is funded by DFG under grant number KA 4320/3-1

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