University of Hull logo

A biomechanical analysis of prognathous and orthognathous insect head capsules: Evidence for a many to one mapping of ridge strain to head strain

Blanke, A.; Pinheiro, M.; Watson, P. J.; Blanke, Alexander; Pinheiro, Manuel; Watson, Peter J.; Fagan, Michael J.


A. Blanke

M. Pinheiro

P. J. Watson


Insect head shapes are remarkably variable but the influences of these changes on biomechanical performance are unclear. Among “basal” winged insects, such as dragonflies, mayflies, earwigs, and stoneflies, some of the most prominent anatomical changes are the general mouthpart orientation, eye size and the connection of the endoskeleton to the head. Here, we assess these variations for the first time using modern engineering methods including multibody dynamics modelling and finite element analysis in order to quantify and compare their influence on overall head performance.

We show that a range of peculiar structures such as the genal/subgenal, epistomal, and circumoccular areas are consistently highly loaded in all species, despite drastically differing morphologies in species with forward projecting (prognathous) and downwards projecting (orthognathous) mouthparts. Sensitivity analyses show that the presence of eyes has a negligible influence on head capsule strain if a circumoccular ridge is present. In contrast, the connection of the dorsal endoskeletal arms to the head capsule especially affects overall head loading in species with downward projecting mouthparts. Analysis of the relative strains between species for each head region reveals that most head regions map onto a similar biomechanical performance space thus showing a many to one mapping of differing forms to the same functional space. Concerted changes in head substructures such as the subgenal area, the endoskeleton and the epistomal area lead to a consistent relative loading pattern in prognathous and orthognathous insects. It appears that biting-chewing loads are managed by a system of strengthening ridges on the head capsule irrespective of the general mouthpart and head orientation. Concerted changes in ridge and endoskeleton configuration allow more radical anatomical changes such as general mouthpart orientation which could be an explanation for the variability of this trait among insects. In an evolutionary context, many to one mapping of diverse forms to similar functions indeed could have fostered the dynamic diversification processes seen in insects.

Journal Article Type Article
Publication Date May 10, 2018
Journal Journal of Evolutionary Biology
Print ISSN 1010-061X
Electronic ISSN 1420-9101
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 31
Issue 5
Pages 665-674
Keywords Ecology, Evolution, Behavior and Systematics
Publisher URL
Copyright Statement ©2018 University of Hull
Additional Information This is the peer reviewed version of the following article: Blanke, A., Pinheiro, M., Watson, P. J. and Fagan, M. J. (), A biomechanical analysis of prognathous and orthognathous insect head capsules: Evidence for a many to one mapping of ridge strain to head strain. J. Evol. Biol.. Accepted Author Manuscript. doi:10.1111/jeb.13251, which has been published in final form at http://onlinelibrary.wi...111/jeb.13251/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.


You might also like

Downloadable Citations