1
|
Klunk CL, Heethoff M, Hammel JU, Gorb SN, Krings W. Mechanical and elemental characterization of ant mandibles: consequences for bite mechanics. Interface Focus 2024; 14:20230056. [PMID: 38618235 PMCID: PMC11008963 DOI: 10.1098/rsfs.2023.0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/16/2024] [Indexed: 04/16/2024] Open
Abstract
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.
Collapse
Affiliation(s)
- Cristian L. Klunk
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, Darmstadt 64287, Germany
| | - Michael Heethoff
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, Darmstadt 64287, Germany
| | - Jörg U. Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - Stanislav N. Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
| | - Wencke Krings
- Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
- Department of Cariology, Endodontology and Periodontology, Universität Leipzig, Liebigstraße 12, Leipzig, Germany
- Department of Electron Microscopy, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, Hamburg 20146, Germany
| |
Collapse
|
2
|
Roth S, Siva-Jothy MT, Balvín O, Morrow EH, Willassen E, Reinhardt K. The evolution of female-biased genital diversity in bedbugs (Cimicidae). Evolution 2024; 78:329-341. [PMID: 38006287 DOI: 10.1093/evolut/qpad211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 11/13/2023] [Accepted: 11/23/2023] [Indexed: 11/27/2023]
Abstract
Rapid genitalia evolution is believed to be mainly driven by sexual selection. Recently, noncopulatory genital functions have been suggested to exert stronger selection pressure on female genitalia than copulatory functions. In bedbugs (Cimicidae), the impact of the copulatory function can be isolated from the noncopulatory impact. Unlike in other taxa, female copulatory organs have no function in egg-laying or waste-product expulsion. Males perform traumatic mating by piercing the female integument, thereby imposing antagonistic selection on females and suspending selection to morphologically match female genitalia. We found the location of the copulatory organ evolved rapidly, changing twice between dorsal and ventral sides, and several times along the anteroposterior and the left-right axes. Male genital length and shape varied much less, did not appear to follow the positional changes seen in females, and showed no evidence for coevolution. Female genitalia position evolved 1.5 times faster than male genital length and shape and showed little neutral or geographic signals. Instead, we propose that nonmorphological male traits, such as mating behavior, may drive female genitalia morphology in this taxon. Models of genitalia evolution may benefit from considering morphological genital responses to nonmorphological stimuli, such as male mating behavior or copulatory position.
Collapse
Affiliation(s)
- Steffen Roth
- University Museum of Bergen, University of Bergen, NO-5020 Bergen, Norway
| | - Michael T Siva-Jothy
- OAP, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Ondřej Balvín
- Department of Ecology, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - Edward H Morrow
- Department of Environmental and Life Sciences, Karlstad University, Karlstad, Sweden
| | - Endre Willassen
- University Museum of Bergen, University of Bergen, NO-5020 Bergen, Norway
| | - Klaus Reinhardt
- Applied Zoology, Faculty of Biology, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
3
|
Klunk CL, Argenta MA, Rosumek FB, Schmelzle S, van de Kamp T, Hammel JU, Pie MR, Heethoff M. Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading. Sci Rep 2023; 13:16833. [PMID: 37803099 PMCID: PMC10558566 DOI: 10.1038/s41598-023-43944-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/30/2023] [Indexed: 10/08/2023] Open
Abstract
Insects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks.
Collapse
Affiliation(s)
- C L Klunk
- Graduate Program in Ecology and Conservation, Universidade Federal do Paraná, Centro Politécnico, Av. Cel. Francisco H. dos Santos, 100 - Jardim das Américas, Curitiba, PR, 81531-980, Brazil.
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany.
| | - M A Argenta
- Department of Civil Construction, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - F B Rosumek
- Department of Ecology and Zoology, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - S Schmelzle
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany
| | - T van de Kamp
- Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
- Laboratory for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - J U Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - M R Pie
- Biology Department, Edge Hill University, Ormskirk, Lancashire, UK
| | - M Heethoff
- Animal Evolutionary Ecology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany.
| |
Collapse
|
4
|
Krings W, Matsumura Y, Brütt JO, Gorb SN. Material gradients in gastropod radulae and their biomechanical significance: a combined approach on the paludomid Lavigeria grandis. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2022; 109:52. [PMID: 36322292 PMCID: PMC9630255 DOI: 10.1007/s00114-022-01822-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/17/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
The radula, a chitinous membrane spiked with teeth, is the molluscan autapomorphy for the gathering and processing of food. The teeth, as actual interfaces between the organism and the ingesta, act as load transmitting regions and have to withstand high stresses during foraging - without structural failure or high degrees of wear. Mechanisms contributing to this were studied previously in paludomid gastropods from Lake Tanganyika. For some species, gradients in hardness and Young's modulus along the teeth were detected, enabling the bending and relying of teeth onto the next row, distributing the stresses more equally. The here presented study on one of them - Lavigeria grandis - aims at shedding light on the origin of these functional gradients. The mechanical properties were identified by nanoindentation technique and compared to the elemental composition, determined by elemental dispersive X-ray spectroscopy (EDX, EDS). This was done for the complete radular (mature and immature tooth rows), resulting in overall 236 EDX and 700 nanoindentation measurements. Even though teeth showed regional differences in elemental composition, we could not correlate the mechanical gradients with the elemental proportions. By applying confocal laser scanning microscopy (CLSM), we were finally able to relate the mechanical properties with the degree of tanning. CLSM is a common technique used on arthropod cuticle, but was never applied on radular teeth before. In general, we found that nanoindentation and CLSM techniques complement one another, as for example, CLSM is capable of revealing heterogeneities in material or micro-gradients, which leads to a better understanding of the functionalities of biological materials and structures.
Collapse
Affiliation(s)
- Wencke Krings
- Department of Behavioral Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
- Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
- Department of Functional Morphology and Biomechanics, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
| | - Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
- Department of General and Systematic Zoology, Zoological Institute and Museum, Universität Greifswald, Loitzer Str. 26, 17489, Greifswald, Germany
| | - Jan-Ole Brütt
- Department of Behavioral Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
- Department of Mammalogy and Palaeoanthropology, Leibniz Institute for the Analysis of Biodiversity Change, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoologisches Institut, Christian-Albrechts-Universität Zu Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| |
Collapse
|
5
|
Li C, Gorb SN, Rajabi H. Biomechanical strategies to reach a compromise between stiffness and flexibility in hind femora of desert locusts. Acta Biomater 2021; 134:490-498. [PMID: 34293506 DOI: 10.1016/j.actbio.2021.07.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 11/28/2022]
Abstract
Insect cuticle can reach a wide range of material properties, which is thought to be the result of adaptations to applied mechanical stresses. Biomechanical mechanisms behind these property variations remain largely unknown. To fill this gap, here we performed a comprehensive study by simultaneous investigation of the microstructure, sclerotization and the elasticity modulus of the specialized cuticle of the femora of desert locusts. We hypothesized that, considering their different roles in jumping, the femora of fore-, mid- and hind legs should be equipped with cuticles that have different mechanical properties. Surprisingly, our results showed that the hind femur, which typically bears higher stresses, has a lower elasticity modulus than the fore and mid femora in the longitudinal direction. This is likely due to the lower sclerotization and different microstructure of the hind femur cuticle. This allows for some deformability in the femur wall and is likely to reduce the risk of mechanical failure. In contrast to both other femora, the hind femur is also equipped with a set of sclerotized ridges that are likely to provide it with the required stiffness to withstand the mechanical loads during walking and jumping. This paper is one of only a few comprehensive studies on insect cuticle, which advances the current understanding of the relationship between the structure, material property and function in this complex biological composite. STATEMENT OF SIGNIFICANCE: Insect cuticle is a biological composite with strong anisotropy and wide ranges of material properties. Using an example of the femoral cuticle of desert locusts, we measured the elasticity modulus, microstructure and sclerotization level of the cuticle. Our results show that, although the hind femur withstands most of the stress during locomotion, it has a lower elasticity modulus than the fore and mid femora. This is likely to be a functional adaption to jumping, in order to allow small deformations of the femur wall and reduce the risk of material failure. Our results deepen the current understanding of the structure-material-function relationship in the complex insect cuticle.
Collapse
Affiliation(s)
- Chuchu Li
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany.
| | - Stanislav N Gorb
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany
| | - Hamed Rajabi
- Functional Morphology and Biomechanics, Institute of Zoology, Kiel University, Kiel, Germany; Division of Mechanical Engineering and Design, School of Engineering, London South Bank University, London, UK
| |
Collapse
|
6
|
Matsumura Y, Kovalev A, Gorb SN. Mechanical properties of a female reproductive tract of a beetle and implications for penile penetration. Proc Biol Sci 2021; 288:20211125. [PMID: 34229492 DOI: 10.1098/rspb.2021.1125] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Coevolution of male and female genitalia is widespread in animals. Nevertheless, few studies have examined the mechanics of genital interactions during mating. We characterized the mechanical properties of the elongated female genitalia, the spermathecal duct, of the small cassidine beetle, Cassida rubiginosa. The data were compared with the mechanical properties of the elongated male genitalia, the flagellum. We analysed the material distributions of the spermathecal duct using a microscopy technique, established a tensile test setup under a light microscope and conducted tensile tests. Diameter and tensile stiffness gradients were present along the spermathecal duct, but its Young's modulus and material distribution were more or less homogeneous. The results confirmed the hypothesis based on numerical simulations that the spermathecal duct is more rigid than the flagellum. In the study species, the penile penetration force is simply applied to the base of the hyper-elongated flagellum and conveyed along the flagellum to its tip. Considering this simple penetration mechanism, the relatively low flexibility of the spermathecal duct, compared to the flagellum, is likely to be essential for effective penetration of the flagellum.
Collapse
Affiliation(s)
- Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Alexander Kovalev
- Department of Functional Morphology and Biomechanics, Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| |
Collapse
|
7
|
Klunk CL, Argenta MA, Casadei-Ferreira A, Economo EP, Pie MR. Mandibular morphology, task specialization and bite mechanics in Pheidole ants (Hymenoptera: Formicidae). J R Soc Interface 2021; 18:20210318. [PMID: 34102082 PMCID: PMC8187013 DOI: 10.1098/rsif.2021.0318] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/17/2021] [Indexed: 11/12/2022] Open
Abstract
Ants show remarkable ecological and evolutionary success due to their social life history and division of labour among colony members. In some lineages, the worker force became subdivided into morphologically distinct individuals (i.e. minor versus major workers), allowing for the differential performance of particular roles in the colony. However, the functional and ecological significance of these morphological differences are not well understood. Here, we applied finite element analysis (FEA) to explore the biomechanical differences between major and minor ant worker mandibles. Analyses were carried out on mandibles of two Pheidole species, a dimorphic ant genus. We tested whether major mandibles evolved to minimize stress when compared to minors using combinations of the apical tooth and masticatory margin bites under strike and pressure conditions. Majors performed better in pressure conditions yet, contrary to our expectations, minors performed better in strike bite scenarios. Moreover, we demonstrated that even small morphological differences in ant mandibles might lead to substantial differences in biomechanical responses to bite loading. These results also underscore the potential of FEA to uncover biomechanical consequences of morphological differences within and between ant workers.
Collapse
Affiliation(s)
- Cristian L. Klunk
- Graduate Program in Ecology and Conservation, Federal University of Paraná, Curitiba-PR, Brazil
| | - Marco A. Argenta
- Department of Civil Construction, Federal University of Paraná, Curitiba-PR, Brazil
| | - Alexandre Casadei-Ferreira
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Evan P. Economo
- Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Marcio R. Pie
- Graduate Program in Ecology and Conservation, Federal University of Paraná, Curitiba-PR, Brazil
- Department of Zoology, Federal University of Paraná, Curitiba-PR, Brazil
| |
Collapse
|