The rove beetles (Insecta, Coleoptera, Staphylinidae) are mainly predators. They use the mandible of their mouthparts to bite food. According to previous morphological studies, three different types of mandibles and heads can be recognized. Presently, the relationship of the head shapes and the robustness of mandibles in rove beetles as well as in other beetle groups is a matter of debate. The group Molecular systematics and evolution of beetles, Institute of Zoology, CAS studied the relationship between the shape of the mandible, the development of controlling muscles, and the morphology of the posterior part of the head. The results has been pressed on the issue of Analytical and Bioanalytical Chemistry, on May 22, 2011.

We selected three rove beetle species in this study which are Noddia sp., Creophilus maxillosus, and Hesperosoma sp. We reconstructed the three dimensional (3D) structures of their head capsule, mandible and mandible muscles using Xray tomography. From the analysis we found an interesting result connected with the adductor muscles. They are short muscles originatingfrom the posterolateral angle of the head of Noddia sp., whereas the angles with the apodeme are approximately 40°. The muscles are long muscles originating from the posterolateral angles of the head of Creophilus maxillosus and the angles with the apodeme are approximately 30°. In addition, there are no adductor muscles originating from the posterolateral angle of the head except for the mandible abductor muscle in Hesperosoma sp.

We studied the mandible, muscle and skeleton in 3D, which may explain the relationships of different structures more precise. It will also greatly promote the studies of structure and functions, the phylogenesis, as well as evolution of different structures.

Article:

Dee Li, Kai Zhang, Peiping Zhu, Ziyu Wu & Hongzhang Zhou,3D configuration of mandibles and controlling muscles in rove beetles based on micro-CT technique, Anal. Bioanal. Chem., 2011, 401: 817–825.