Head and mandible shapes are highly integrated yet represent two distinct modules within and among worker subcastes of the ant genus <i>Pheidole</i>

Casadei-Ferreira, Alexandre; Friedman, Nicholas R.; Economo, Evan P.; Pie, Márcio R.; Feitosa, Rodrigo M.

doi:10.1002/ece3.7422

Cited by 10 publications

(14 citation statements)

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“…When the anatomical features of an organism present with few or no landmarks or would need entomological dissection [ 18 ], such as in the worker ants in this study or in non-winged insects, juvenile stages, or eggs, the OM approach can be used [ 13 ].…”

Section: Discussionmentioning

confidence: 99%

“…Like the more recent geometric morphometric (GM) technique, OM allows separate analyses for size and shape coupled with visualization. In contrast to the GM method that is based on the relative position of anatomical landmarks (see an application on ants in Katzke et al [ 15 ], Bagherian et al [ 16 ], Seifert et al [ 17 ], and Casadei-Ferreira et al [ 18 ]), the OM method considers only the contours.…”

Section: Introductionmentioning

confidence: 99%

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Species Discrimination of Three Odontomachus (Formicidae: Ponerinae) Species in Thailand Using Outline Morphometrics

Samung

Chaiphongpachara

Ruangsittichai

et al. 2022

Insects

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All members of the ant genus Odontomachus Latreille, 1804 are venomous ants. Four species in this genus have been identified from Thailand: Odontomachus latidens Mayr, 1867; O. monticola Emery, 1892; O. rixosus Smith, 1757; and O. simillimus Smith, 1758. The three latter species are available and have been used for an outline morphometric study. They display similar morphology, which makes their distinction very difficult except for highly qualified individuals. A total of 80 worker specimens were studied, exploring the contour shapes of their head and pronotum as possible taxonomic characters. The size of each body part was estimated determining the contour perimeter, the values for which were largely overlapping between O. rixosus and O. simillimus; most O. monticola specimens exhibited a significantly larger size. In contrast to the size, each contour shape of the head or pronotum established O. rixosus as the most distinct species. An exploratory data analysis disclosed the higher taxonomic signal of the head contour relative to the pronotum one. The scores obtained for validated reclassification were much better for the head (99%) than for the pronotum (82%). This study supports outline morphometrics of the head as a promising approach to contribute to the morphological identification of ant species, at least for monomorphic workers.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Species Discrimination of Three Odontomachus (Formicidae: Ponerinae) Species in Thailand Using Outline Morphometrics

Samung

Chaiphongpachara

Ruangsittichai

et al. 2022

Insects

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“…Ants show a relevant interspecific variation in mandible morphology [78], whereas intraspecific distinctions are also observed, mainly between worker types [79]. How morphological disparity reflects ant biting performance was investigated for some ant lineages by the use of FEA [6][7][8][9][10] as well as through the estimation of relevant mechanical characteristics based on morphological information [80,81], providing compelling evidence about how mandibular morphological variation can influence bite mechanics, but there has been no attempt so far to simulate the effects of variation in the mandible cuticle mechanical properties in its responses to bite loading.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and elemental characterization of ant mandibles: consequences for bite mechanics

Klunk,

Heethoff,

Hammel

et al. 2024

Interface Focus.

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Mandible morphology has an essential role in biting performance, but the mandible cuticle can have regional differences in its mechanical properties. The effects of such a heterogeneous distribution of cuticle material properties in the mandible responses to biting loading are still poorly explored in chewing insects. Here, we tested the mechanical properties of mandibles of the ant species Formica cunicularia by nanoindentation and investigated the effects of the cuticular variation in Young's modulus (E) under bite loading with finite-element analysis (FEA). The masticatory margin of the mandible, which interacts with the food, was the hardest and stiffest region. To unravel the origins of the mechanical property gradients, we characterized the elemental composition by energy-dispersive X-ray spectroscopy. The masticatory margin possessed high proportions of Cu and Zn. When incorporated into the FEA, variation in E effectively changed mandible stress patterns, leading to a relatively higher concentration of stresses in the stiffer mandibular regions and leaving the softer mandible blade with relatively lower stress. Our results demonstrated the relevance of cuticle E heterogeneity in mandibles under bite loading, suggesting that the accumulation of transition metals such as Cu and Zn has a relevant correlation with the mechanical characteristics in F . cunicularia mandibles.

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“…Such a multitask use of the mandibles is commonly observed among ant workers (Wilson 1987; Zhang et al 2020; Richter & Economo 2023), responsible for most of the colony’s non-reproductive activities. Ants show a relevant interspecific variation in mandible morphology (Sosiak & Barden 2021), whereas intraspecific distinctions are also observed, mainly between worker types (Casadei-Ferreira et al 2021). How morphological disparity reflects ant biting performance was investigated for some ant lineages by the application of computational simulations (Larabee et al 2018; Zhang et al 2020; Klunk et al 2021; Wang et al 2022), as well as through the estimation of relevant mechanical characteristics based on morphological information (Püffel et al 2021; 2023a), providing compelling evidence about how mandibular morphological variation can influence bite mechanics.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and elemental characterization of ant mandibles: consequences for bite mechanics

Klunk,

Heethoff,

Hammel

et al. 2023

Preprint

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Chewing with the mandibles is a food processing behavior observed in most current insect lineages. Mandible morphology has an essential role in biting behavior and food processing capacity. However, the mandible cuticle can have regional differences in its mechanical properties, associated or not with the accumulation of elements that increase cuticle stiffness. The effects of such a heterogeneous distribution of cuticle material properties in the mandible responses to biting loading are still poorly explored in chewing insects. Here we measured the elemental composition and material properties of workers of an ant species, <Formica cunicularia>, and tested the effects of the cuticular variation in Young's modulus (E) under bite-loading with Finite Element Analysis (FEA). We divided worker mandibles into four regions that we expect would vary in elemental composition and material properties, namely the masticatory margin, mandible blade, ventral (VMA), and dorsal (DMA) mandibular articulations with the head. Specifically, we expect the masticatory margin will show higher cuticular hardness (H) and E values, followed by the mandibular joints and the mandible blade. We also predict that such cuticle material properties variation is functionally relevant under bite-loading, changing stress patterns when compared to the mechanical responses of a mandible with a homogeneous distribution of material properties. To measure elemental composition, we used energy disperse X-ray spectroscopy, while H and E were accessed through nanoindentation tests. Mandible mechanical responses to bite-loading were tested with FEA, comparing a mandible with a homogeneous versus a heterogeneous E distribution. As expected, the mandibular regions showed distinct proportions of relevant elements, like Cu and Zn, with the masticatory margin showing the higher levels of those elements, followed by the mandibular articulations with the head and the mandible blade. The same pattern was observed regarding the values of cuticle H and E. When incorporated into FEA, this variation in E effectively changed mandible stress patterns, leading to a higher concentration of stresses in the stiffer mandibular regions, letting the softer mandible blade with relatively lower stress levels. Our results demonstrated the relevance of cuticle heterogeneity in mechanical properties to deal with bite-loading demands and suggest that the accumulation of transition metals such as Cu and Zn has a relevant correlation with such mechanical characteristics of the mandible in this ant species.

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Head and mandible shapes are highly integrated yet represent two distinct modules within and among worker subcastes of the ant genus Pheidole

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 10 publications

References 65 publications

Species Discrimination of Three Odontomachus (Formicidae: Ponerinae) Species in Thailand Using Outline Morphometrics

Species Discrimination of Three Odontomachus (Formicidae: Ponerinae) Species in Thailand Using Outline Morphometrics

Mechanical and elemental characterization of ant mandibles: consequences for bite mechanics

Mechanical and elemental characterization of ant mandibles: consequences for bite mechanics

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