The mandibular forces and pressures of some predacious Coleoptera

Wheater, C. Philip; Evans, M. E. G.

doi:10.1016/0022-1910(89)90096-6

Cited by 46 publications

(62 citation statements)

References 10 publications

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“…Also, the estimates for maximal muscle stress in males and females are almost identical (18 and 17 N cm −2 , respectively) and lie well within the range of calculated and measured stresses of (synchronous) insect muscle (2 to 80 N cm ) (Bennet-Clark, 1975;Ellington, 1985;Full and Ahn, 1995;Usherwood, 1962;Wheater and Evans, 1989). All of these arguments not only support the followed procedure to estimate PCSA, but also suggest that there is no intersexual difference in the physiology of the jaw closers of stag beetles, and that the characteristics of these closer muscles are not specialized compared with other (synchronous) insect muscles.…”

Section: Research Articlementioning

confidence: 78%

Biomechanical determinants of bite force dimorphism inCyclommatus metalliferstag beetles

Goyens

Dirckx

Dierick

et al. 2014

Journal of Experimental Biology

172

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In the stag beetle family (Lucanidae), males have diverged from females by sexual selection. The males fight each other for mating opportunities with their enlarged mandibles. It is known that owners of larger fighting apparatuses are favoured to win the male-male fights, but it was unclear whether male stag beetles also need to produce high bite forces while grabbing and lifting opponents in fights. We show that male Cyclommatus metallifer stag beetles bite three times as forcefully as females. This is not entirely unexpected given the spectacular nature of the fights, but all the more impressive given the difficulty of achieving this with their long mandibles (long levers). Our results suggest no increase in male intrinsic muscle strength to accomplish this. However, morphological analyses show that the long mandibular output levers in males are compensated by elongated input levers (and thus a wider anterior side of the head). The surplus of male bite force capability is realized by enlargement of the closer muscles of the mandibles, while overall muscle force direction remained optimal. To enable the forceful bites required to ensure male reproductive success, male head size and shape are adapted for long input levers and large muscles. Therefore, the entire head should be regarded as an integral part of male armature.

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Section: Research Articlementioning

confidence: 78%

Biomechanical determinants of bite force dimorphism inCyclommatus metalliferstag beetles

Goyens

Dirckx

Dierick

et al. 2014

Journal of Experimental Biology

172

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“…Due to the sparse literature record concerning insect bite forces (Wheater & Evans, ; Goyens et al ., ; Weihmann et al ., ; David et al ., ), it was, however, unclear whether insects from these different lineages but with comparable head sizes (and thus muscle volumes) really show larger bite forces. Indeed, the bite forces predicted in the present study are in line with earlier bite force measurements for other insects with comparable head widths and mandibular set‐ups (Wheater & Evans, ; Weihmann et al ., ; David et al ., ). Given the increase in bite force from mayflies to Neoptera, this implies that the morphological changes in the above‐mentioned structures allow a better distribution of the strain resulting from the larger bite forces.…”

Section: Discussionmentioning

confidence: 99%

A biomechanical analysis of prognathous and orthognathous insect head capsules: evidence for a many‐to‐one mapping of form to function

Blanke

Pinheiro

Watson

et al. 2018

J of Evolutionary Biology

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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 as well as differing ridge and sclerite configurations using modern engineering methods including multibody dynamics modelling and finite element analysis in order to quantify and compare the influence of anatomical changes on strain in particular head regions and the whole head. We show that a range of peculiar structures such as the genal/subgenal, epistomal and circumocular areas are consistently highly loaded in all species, despite drastically differing morphologies in species with forward-projecting (prognathous) and downward-projecting (orthognathous) mouthparts. Sensitivity analyses show that the presence of eyes has a negligible influence on head capsule strain if a circumocular 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 concerted changes in head substructures such as the subgenal area, the endoskeleton and the epistomal area lead to a consistent relative loading for the whole head capsule and vulnerable structures such as the eyes. 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 might allow for more radical anatomical changes such as the 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 strain patterns onto a relatively similar overall head loading indeed could have fostered the dynamic diversification processes seen in insects.

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“…In contrast, bite cycles are shorter than in cockroaches and the locust (Blaney and Chapman, 1970;Schmitt et al, 2014). Measured bite force for S. vulgatum is in the range of bite force results for cockroaches (Weihmann et al, 2015) or stag beetles (Cyclommatus metallifer) (Goyens et al, 2014;Wheater and Evans, 1989). Successive bite cycles typically lasted between 30 and 59 s with some of the strongest bite cycles occurring during the end of the measurements (Fig.…”

Section: Discussionmentioning

confidence: 99%

Musculoskeletal modeling of the dragonfly mandible system as an aid to understanding the role of single muscles in an evolutionary context

David

Funken

Potthast

et al. 2016

Journal of Experimental Biology

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Insects show a great variety of mouthpart and muscle configurations; however, knowledge of their mouthpart kinematics and muscle activation patterns is fragmentary. Understanding the role of muscle groups during movement and comparing them between insect groups could yield insights into evolutionary patterns and functional constraints. Here, we developed a mathematical inverse dynamic model including distinct muscles for an insect head-mandiblemuscle complex based on micro-computed tomography (µCT) data and bite force measurements. With the advent of µCT, it is now possible to obtain precise spatial information about muscle attachment areas and head capsule construction in insects. Our model shows a distinct activation pattern for certain fibre groups potentially related to a geometry-dependent optimization. Muscle activation patterns suggest that intramandibular muscles play a minor role in bite force generation, which is a potential reason for their loss in several lineages of higher insects. Our model is in agreement with previous studies investigating fast and slow muscle fibres and is able to resolve the spatio-temporal activation patterns of these different muscle types in insects. The model used here has a high potential for large-scale comparative analyses on the role of different muscle setups and head capsule designs in the megadiverse insects in order to aid our understanding of insect head capsule and mouthpart evolution under mechanical constraints.

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The mandibular forces and pressures of some predacious Coleoptera

Cited by 46 publications

References 10 publications

Biomechanical determinants of bite force dimorphism inCyclommatus metalliferstag beetles

Biomechanical determinants of bite force dimorphism inCyclommatus metalliferstag beetles

A biomechanical analysis of prognathous and orthognathous insect head capsules: evidence for a many‐to‐one mapping of form to function

Musculoskeletal modeling of the dragonfly mandible system as an aid to understanding the role of single muscles in an evolutionary context

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