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Katsuki M, Uesugi K, Yokoi T, Ozawa T, O'Brien DM, Emlen DJ, Okada K, Okada Y. Morphological and functional analyses for investigation of sexually selected legs in the frog legged beetle Sagra femorata (Coleoptera: Chrysomelidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2024; 80:101360. [PMID: 38704965 DOI: 10.1016/j.asd.2024.101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/07/2024]
Abstract
Mate choice and male-male combat over successful mating often cause disproportionate exaggeration of male trait relative to body size. However, the exaggeration is often not the only trait involved with male-male combat and mate choice: suites of co-expressed traits may function together as a coordinated unit. When this occurs, dimorphism may be expected for these additional, non-exaggerated, structures. S. femorata males have disproportionately large hind-legs used in male-male combat over females. During the fights, fore- and mid-legs are used to keep males in positions where advantageous for leverage. Because use of the exaggerated hind-legs is coordinated with the other legs, they will coevolve as a functional unit. Here, we show that 1) S. femorata has sexual size differences in all three legs; 2) males show positive allometry in the relative sizes of all three legs; and 3) microstructures of tarsi on the fore- and mid-legs are also sexually dimorphic. Despite these differences in the tarsal microstructure, 4) adhesion forces of the tarsi had no sexual difference in flat surface. The microstructure would be specialized on attaching elytra surface. These results suggest that the three pairs of legs function together during fighting behavior, with hind-legs employed primarily for fighting, and the fore- and mid-legs functioning to grip females, keeping males positioned on the back of the female during combat.
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Affiliation(s)
- Masako Katsuki
- Department of Agricultural and Environmental Biology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan; Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
| | - Kaoru Uesugi
- Department of Mechanical Systems Engineering, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa-cho, Hitachi, Ibaraki 316-8511, Japan
| | - Tomoyuki Yokoi
- Graduate School of Science and Technology, University of Tsukuba, Japan
| | - Takane Ozawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan
| | - Devin M O'Brien
- Department of Natural Sciences, SUNY Cobleskill, Cobleskill, NY, 12043, USA
| | - Douglas J Emlen
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, Japan
| | - Kensuke Okada
- Faculty of Environmental, Life, Natural Science and Technology, Okayama University, Tsushima-naka 111, Okayama 700-8530, Japan
| | - Yasukazu Okada
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
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2
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Yu G, Wong BH, Painting CJ, Li H, Yu L, Zhang Z, Zhang S, Li D. Males armed with big weapons win fights at limited cost in ant-mimicking jumping spiders. Curr Zool 2024; 70:98-108. [PMID: 38476142 PMCID: PMC10926263 DOI: 10.1093/cz/zoac101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/18/2022] [Indexed: 03/14/2024] Open
Abstract
A core assumption of sexual selection theory is that sexually selected weapons, specialized morphological structures used directly in male contests, can improve an individual's reproductive success but only if the bearer can overcome associated costs, the negative effects on the bearer's fitness components. However, recent studies have shown that producing and wielding exaggerated weapons may not necessarily be costly. Rather, some traits can be selected for supporting, or compensating for, the expense of producing and wielding such exaggerated weapons. In the ant-mimicking jumping spider Myrmarachne gisti, exaggerated chelicerae are borne only by adult males and not females, showing sexual dimorphism and steep positive allometry with body size. Here, we determine the potential benefits of bearing exaggerated chelicerae during male contests and explore the potential for costs in terms of prey-capture efficiency and compensation between chelicera size and neighboring trait size. While males with longer chelicerae won most of their male-male contests, we found no significant differences in prey-capture efficiency between males and females regardless of whether prey was winged or flightless. Males' elongated chelicerae thus do not impede their efficiency at capturing prey. Furthermore, we found that the sizes of all neighboring traits are positively correlated with chelicera size, suggesting that these traits may be under correlational selection. Taken together, our findings suggest that M. gisti males armed with the exaggerated chelicerae that function as weapons win more fights at limited cost for performance in prey capture and compensate for neighboring structures.
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Affiliation(s)
- Guocheng Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering and Centre for Behavioral Ecology and Evolution, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Boon Hui Wong
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Christina J Painting
- Te Aka Mātuatua School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Hongze Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering and Centre for Behavioral Ecology and Evolution, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Long Yu
- State Key Laboratory of Biocatalysis and Enzyme Engineering and Centre for Behavioral Ecology and Evolution, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Zengtao Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering and Centre for Behavioral Ecology and Evolution, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Shichang Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering and Centre for Behavioral Ecology and Evolution, School of Life Sciences, Hubei University, Wuhan 430062, China
| | - Daiqin Li
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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3
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Weber JN, Kojima W, Boisseau RP, Niimi T, Morita S, Shigenobu S, Gotoh H, Araya K, Lin CP, Thomas-Bulle C, Allen CE, Tong W, Lavine LC, Swanson BO, Emlen DJ. Evolution of horn length and lifting strength in the Japanese rhinoceros beetle Trypoxylus dichotomus. Curr Biol 2023; 33:4285-4297.e5. [PMID: 37734374 DOI: 10.1016/j.cub.2023.08.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/28/2023] [Accepted: 08/23/2023] [Indexed: 09/23/2023]
Abstract
What limits the size of nature's most extreme structures? For weapons like beetle horns, one possibility is a tradeoff associated with mechanical levers: as the output arm of the lever system-the beetle horn-gets longer, it also gets weaker. This "paradox of the weakening combatant" could offset reproductive advantages of additional increases in weapon size. However, in contemporary populations of most heavily weaponed species, males with the longest weapons also tend to be the strongest, presumably because selection drove the evolution of compensatory changes to these lever systems that ameliorated the force reductions of increased weapon size. Therefore, we test for biomechanical limits by reconstructing the stages of weapon evolution, exploring whether initial increases in weapon length first led to reductions in weapon force generation that were later ameliorated through the evolution of mechanisms of mechanical compensation. We describe phylogeographic relationships among populations of a rhinoceros beetle and show that the "pitchfork" shaped head horn likely increased in length independently in the northern and southern radiations of beetles. Both increases in horn length were associated with dramatic reductions to horn lifting strength-compelling evidence for the paradox of the weakening combatant-and these initial reductions to horn strength were later ameliorated in some populations through reductions to horn length or through increases in head height (the input arm for the horn lever system). Our results reveal an exciting geographic mosaic of weapon size, weapon force, and mechanical compensation, shedding light on larger questions pertaining to the evolution of extreme structures.
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Affiliation(s)
- Jesse N Weber
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Wataru Kojima
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8511, Japan
| | - Romain P Boisseau
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
| | - Teruyuki Niimi
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki 444-8585, Japan
| | - Shinichi Morita
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki 444-8585, Japan
| | - Shuji Shigenobu
- Trans-Scale Biology Center, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki 444-8585, Japan
| | - Hiroki Gotoh
- Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, 836 Oya, Suruga Ward, Shizuoka, Japan
| | - Kunio Araya
- Faculty of Social and Cultural Studies, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka-city Fukuoka 819-0395, Japan
| | - Chung-Ping Lin
- Department of Life Science, National Taiwan Normal University, No.88 Sec. 4, Tingzhou Rd, Taipei 11677, Taiwan
| | - Camille Thomas-Bulle
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA; Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Cerisse E Allen
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
| | - Wenfei Tong
- Cornell Laboratory of Ornithology, Ithaca, NY 14850, USA
| | - Laura Corley Lavine
- Department of Entomology, Washington State University, Pullman, WA 99164, USA
| | - Brook O Swanson
- Department of Biology, Gonzaga University, 502 East Boone Avenue, Spokane, WA 99258-0102, USA
| | - Douglas J Emlen
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA.
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4
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Morita S, Shibata TF, Nishiyama T, Kobayashi Y, Yamaguchi K, Toga K, Ohde T, Gotoh H, Kojima T, Weber JN, Salvemini M, Bino T, Mase M, Nakata M, Mori T, Mori S, Cornette R, Sakura K, Lavine LC, Emlen DJ, Niimi T, Shigenobu S. The draft genome sequence of the Japanese rhinoceros beetle Trypoxylus dichotomus septentrionalis towards an understanding of horn formation. Sci Rep 2023; 13:8735. [PMID: 37253792 DOI: 10.1038/s41598-023-35246-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 05/15/2023] [Indexed: 06/01/2023] Open
Abstract
The Japanese rhinoceros beetle Trypoxylus dichotomus is a giant beetle with distinctive exaggerated horns present on the head and prothoracic regions of the male. T. dichotomus has been used as a research model in various fields such as evolutionary developmental biology, ecology, ethology, biomimetics, and drug discovery. In this study, de novo assembly of 615 Mb, representing 80% of the genome estimated by flow cytometry, was obtained using the 10 × Chromium platform. The scaffold N50 length of the genome assembly was 8.02 Mb, with repetitive elements predicted to comprise 49.5% of the assembly. In total, 23,987 protein-coding genes were predicted in the genome. In addition, de novo assembly of the mitochondrial genome yielded a contig of 20,217 bp. We also analyzed the transcriptome by generating 16 RNA-seq libraries from a variety of tissues of both sexes and developmental stages, which allowed us to identify 13 co-expressed gene modules. We focused on the genes related to horn formation and obtained new insights into the evolution of the gene repertoire and sexual dimorphism as exemplified by the sex-specific splicing pattern of the doublesex gene. This genomic information will be an excellent resource for further functional and evolutionary analyses, including the evolutionary origin and genetic regulation of beetle horns and the molecular mechanisms underlying sexual dimorphism.
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Grants
- 23128505, 25128706, 16H01452, 18H04766, 20H04933, 20H05944, 17H06384, 22128008, 19K16181, 21K15135 Japan Society for the Promotion of Science
- 23128505, 25128706, 16H01452, 18H04766, 20H04933, 20H05944, 17H06384, 22128008, 19K16181, 21K15135 Japan Society for the Promotion of Science
- 23128505, 25128706, 16H01452, 18H04766, 20H04933, 20H05944, 17H06384, 22128008, 19K16181, 21K15135 Japan Society for the Promotion of Science
- 23128505, 25128706, 16H01452, 18H04766, 20H04933, 20H05944, 17H06384, 22128008, 19K16181, 21K15135 Japan Society for the Promotion of Science
- IOS-1456133 National Science Foundation
- IOS-1456133 National Science Foundation
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Affiliation(s)
- Shinichi Morita
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Japan
| | - Tomoko F Shibata
- Division of Evolutionary Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Tomoaki Nishiyama
- Division of Integrated Omics Research, Research Center for Experimental Modeling of Human Disease, Kanazawa University, Kanazawa, Japan
| | - Yuuki Kobayashi
- Laboratory of Evolutionary Genomics, National Institute for Basic Biology, Okazaki, Japan
| | - Katsushi Yamaguchi
- Trans-Omics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Kouhei Toga
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- URA Division, Office of Research and Academia-Government-Community Collaboration, Hiroshima University, Hiroshima, Japan
| | - Takahiro Ohde
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Department of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hiroki Gotoh
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka, Japan
| | - Takaaki Kojima
- Laboratory of Molecular Biotechnology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
- Department of Agrobiological Resources, Faculty of Agriculture, Meijo University, Nagoya, Japan
| | - Jesse N Weber
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Marco Salvemini
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Takahiro Bino
- Trans-Omics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Mutsuki Mase
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Moe Nakata
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Tomoko Mori
- Trans-Omics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Shogo Mori
- Trans-Omics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Richard Cornette
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Kazuki Sakura
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Japan
| | - Laura C Lavine
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Douglas J Emlen
- Division of Biological Sciences, The University of Montana, Missoula, MT, USA
| | - Teruyuki Niimi
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Japan.
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Japan.
- Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
| | - Shuji Shigenobu
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Japan.
- Laboratory of Evolutionary Genomics, National Institute for Basic Biology, Okazaki, Japan.
- Trans-Omics Facility, National Institute for Basic Biology, Okazaki, Japan.
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5
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He J, Liu Q, Wang P, Liu B, Sun W, Pan B. Sex dimorphism in the deutonymphs of Dermanyssus gallinae (De Geer, 1778) based on geometric morphometrics. Exp Parasitol 2023; 249:108530. [PMID: 37040857 DOI: 10.1016/j.exppara.2023.108530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/29/2023] [Accepted: 04/05/2023] [Indexed: 04/13/2023]
Abstract
The lifecycle of poultry red mite (PRM), Dermanyssus gallinae,includes several stages and only the adult has been reported to have sex discrimination based on body structures and color patterns. Currently, it's still unknown how to distinguish two sexes of deutonymphs. We measured body length of 254 engorged deutonymphs and examined body size and shape variation of 104 engorged deutonymphs using geometric morphometric techniques. Our findings showed that deutonymph females (with average values of 813.08 μm) had a longer body length than deutonymph males (713.39 μm). Additionally, deutonymph females were found to had a narrow and elongated posterior body shape while deutonymph males had a suboval shape, and the former was bigger than the latter. These results suggest that there is sexual dimorphism in PRM deutonymphs, and the differentiation of deutonymph females and males based on their body length, shape, and size will facilitate a better understanding of reproductive behavior and the accurate population dynamics of PRMs.
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Affiliation(s)
- Jiaqi He
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China
| | - Qi Liu
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China
| | - Penglong Wang
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China
| | - Boxing Liu
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China
| | - Weiwei Sun
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China.
| | - Baoliang Pan
- College of Veterinary Medicine, China Agricultural University, Hai Dian District, Beijing, 100193, China.
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6
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Sizing up swords: Correlated evolution of antlers and tusks in ruminants. J MAMM EVOL 2022. [DOI: 10.1007/s10914-022-09628-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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7
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Ohtsu I, Chikami Y, Umino T, Gotoh H. Evaluation of Body Size Indicators for Morphological Analyses in Two Sister Species of Genus Dorcus (Coleoptera, Lucanidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2022; 22:7. [PMID: 36130316 PMCID: PMC9492273 DOI: 10.1093/jisesa/ieac054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Indexed: 06/15/2023]
Abstract
The relationship between trait and body size, i.e., the scaling relationship or static allometry, is an essential concept for investigating trait size. However, usage of an inappropriate body size indicator can lead to misinterpretation of morphology. In this study, we examined several possible body size indicators in two closely related stag beetle species, Dorcus rectus and Dorcus amamianus. We raised animals in captivity and used pupal weight as a measure of true, or overall body size, and then evaluated six adult morphological traits to test whether these traits could be reliably used as body size indicators in static scaling relationship comparisons. We analyzed two comparisons, between sexes in same species and between species in same sex. We showed that the most appropriate body size indicators differ depending on the comparisons. Our results indicated that the scaling relationship of focal traits could be over- or under-estimated depending on which body size indicators are used.
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Affiliation(s)
- Itsuki Ohtsu
- Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Yasuhiko Chikami
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Okazaki, Aichi, 444-8585, Japan
| | - Taichi Umino
- Sugadaira Research Station, Mountain Science Center, University of Tsukuba, Ueda, Nagano, 386-2204, Japan
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Rhebergen FT, Stewart KA, Smallegange IM. Nutrient-dependent allometric plasticity in a male-diphenic mite. Ecol Evol 2022; 12:e9145. [PMID: 35928796 PMCID: PMC9343935 DOI: 10.1002/ece3.9145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022] Open
Abstract
Male secondary sexual traits often scale allometrically with body size. These allometries can be variable within species and may shift depending on environmental conditions, such as food quality. Such allometric plasticity has been hypothesized to initiate local adaptation and evolutionary diversification of scaling relationships, but is under-recorded, and its eco-evolutionary effects are not well understood. Here, we tested for allometric plasticity in the bulb mite (Rhizoglyphus robini), in which large males tend to develop as armed adult fighters with thickened third legs, while small males become adult scramblers without thickened legs. We first examined the ontogenetic timing for size- and growth-dependent male morph determination, using experimentally amplified fluctuations in growth rate throughout juvenile development. Having established that somatic growth and body size determine male morph expression immediately before metamorphosis, we examined whether the relationship between adult male morph and size at metamorphosis shifts with food quality. We found that the threshold body size for male morph expression shifts toward lower values with deteriorating food quality, confirming food-dependent allometric plasticity. Such allometric plasticity may allow populations to track prevailing nutritional conditions, potentially facilitating rapid evolution of allometric scaling relationships.
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Affiliation(s)
- Flor T. Rhebergen
- Institute for Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamThe Netherlands
| | - Kathryn A. Stewart
- Institute for Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamThe Netherlands
- Institute of Environmental SciencesLeiden UniversityLeidenThe Netherlands
| | - Isabel M. Smallegange
- Institute for Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamThe Netherlands
- School of Natural and Environmental SciencesNewcastle UniversityNewcastle upon TyneUK
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9
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Reproductive Apparatus, Gonadic Maturation, and Allometry of Cyclocephala barrerai Martínez (Coleoptera: Melolonthidae: Dynastinae). INSECTS 2022; 13:insects13070638. [PMID: 35886814 PMCID: PMC9320705 DOI: 10.3390/insects13070638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/10/2022] [Accepted: 07/14/2022] [Indexed: 11/30/2022]
Abstract
Simple Summary Cyclocephala barrerai larvae feed on the roots of ornamental and commercial grasses. Most of their biology is still unknown, and there are no tools to manage their populations. The objective of this work was to study the reproductive system, gonadic maturation, and allometry of C. barrerai. This is the first report into the Melolonthidae family that characterizes the reproductive apparatus, gonadic maturation of both sexes, and allometric relationships of virgin F1 specimens. Adults do not feed, so gonadic maturation depends on larvae reserves. Females present sclerotized accessory glands and a genital chamber with muscular fibers and bacteria. The morphology of the parameres and the antennae are under sexual selection. This is the first report of two main differences among sexes: females are heavier while males have longer antennae. Males and females exhibit allometric relationships that can be used to predict the bodyweight of field-collected specimens. Abstract The Order Coleoptera provides good examples of morphological specializations in the reproductive apparatus, gonadic maturation, and allometry differing between the sexes. The female and male reproductive apparatus has been modified to ensure reproduction between individuals of the same species. The genus Cyclocephala has more than 500 species distributed in America, and Cyclocephala barrerai Martínez is an economically important species in the central part of Mexico. The objective of this work was to study the reproductive system, gonadic maturation, and allometry of C. barrerai. We used light, scanning electron, and laser scanning confocal microscopy to describe the reproductive apparatus and gonadic maturation of females and males. The relationship between adult weight and different parts of the body was established by linear regression. Regardless, the reproductive apparatuses of C. barrerai are like those of other Melolonthidae: the genital chamber, the type II accessory glands, and the ventral plaques of the female and the ejaculator bulb and genital capsule of the males are specific to C. barrerai. The gonads are fully developed when 18 d old. The weight of adult C. barrerai has a positive linear relationship with distinct parts of its body, while the antennae of males are larger than those of the females.
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10
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Réveillion F, Montuire S, Maquart PO, Fétiveau C, Bollache L. Variations in the carapace shape of whip spiders (Arachnida: Amblypygi). J Morphol 2022; 283:1003-1014. [PMID: 35670656 DOI: 10.1002/jmor.21485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 05/03/2022] [Accepted: 05/21/2022] [Indexed: 11/06/2022]
Abstract
Morphological studies often need to reference body size to correctly characterise the shape of organisms. In arthropods, the most commonly used reference for this is the length or width of the carapace, thorax, or the prosoma in the case of chelicerates. However, in the case of animals with unlimited growth, such as whip spiders, this measure could be irrelevant if growth is allometric. In this study, we analyse the ontogenetic modifications in prosoma outline shape in whip spiders during growth and compare the differences in shape between species. Differences are important for the relative prosoma width between species and, in the case of Damon medius, during growth in the juvenile stages, whereas the shape remains stable in mature stages. We conclude that a one-dimensional measure (i.e., length or width) suffices for mature specimens of a single species or family, but for larger studies, or when including immature specimens, at least the prosoma area (within the outline shape) should be used as a size estimator.
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Affiliation(s)
- Florian Réveillion
- Université de Bourgogne Franche Comté, Dijon, France.,Laboratoire Chrono-Environnement, UMR 6249, CNRS, Université Bourgogne Franche-Comté, Besançon, France
| | - Sophie Montuire
- Biogéosciences, UMR 6282, CNRS, Université Bourgogne Franche-Comté, Dijon, France.,EPHE, PSL University, Dijon, France
| | - Pierre-Olivier Maquart
- Medical and Veterinary Entomology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | | | - Loïc Bollache
- Université de Bourgogne Franche Comté, Dijon, France.,Laboratoire Chrono-Environnement, UMR 6249, CNRS, Université Bourgogne Franche-Comté, Besançon, France
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11
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Morita S, Sakura K, Gotoh H, Emlen DJ, Niimi T. Recent advances in understanding horn formation in the Japanese rhinoceros beetle Trypoxylus dichotomus using next-generation sequencing technology. CURRENT OPINION IN INSECT SCIENCE 2022; 51:100901. [PMID: 35301164 DOI: 10.1016/j.cois.2022.100901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 02/20/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
The exaggerated horns of beetles are attractive models for studying the origin of novel traits and morphological evolution. Closely related species often differ profoundly in the size, number, and shape of their horns, and in the body region from which they extend. In addition, beetle horns exhibit exquisite nutrition-dependent phenotypic plasticity, leading to disproportionate growth of the horns in the largest, best-condition individuals and much smaller - even stunted - horn sizes in poor-condition individuals. These exciting phenomena in beetle horns have recently been revealed at the molecular level with the advent of next-generation sequencing. This section reviews the latest research on a horned beetle, the Japanese rhinoceros beetle Trypoxylus dichotomus, whose genome was recently sequenced.
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Affiliation(s)
- Shinichi Morita
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan; Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Kazuki Sakura
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
| | - Hiroki Gotoh
- Department of Biological Science, Faculty of Sciences, Shizuoka University, Shizuoka 422-8529, Japan
| | - Douglas J Emlen
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Teruyuki Niimi
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan.
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13
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Palaoro AV, García-Hernández S, Buzatto BA, Machado G. Function predicts the allometry of contest-related traits, but not sexual or male dimorphism in the amazonian tusked harvestman. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10152-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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OUP accepted manuscript. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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15
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Reeves JT, Fuhlendorf SD, Davis CA, Wilder SM. Arthropod prey vary among orders in their nutrient and exoskeleton content. Ecol Evol 2021; 11:17774-17785. [PMID: 35003638 PMCID: PMC8717265 DOI: 10.1002/ece3.8280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 10/02/2021] [Accepted: 10/06/2021] [Indexed: 11/20/2022] Open
Abstract
Insectivores gain macronutrients and elements from consuming arthropod prey, but must also deal with indigestible components (i.e., exoskeleton) of prey. For example, avian chicks (e.g., northern bobwhites; Colinus virginianus) have limited gut space, and ingesting prey with relatively higher proportions of indigestible components may impact assimilation efficiency, growth, and survival. The ability of insectivores to choose higher quality prey would depend on prey taxa varying consistently in nutritional content. We tested whether there were consistent differences among taxonomic orders of arthropod prey in their macronutrient (protein and lipid), elemental (C and N), and exoskeleton content. We used northern bobwhite chicks as our focal insectivore and focused on their potential prey as a case study. We also tested the influence of indigestible exoskeleton on the measurement of macronutrient content and the ability of elemental content to predict macronutrients. We found large and consistent variation in macronutrient and elemental content between arthropod orders. Some orders had consistently high protein content and low exoskeleton content (i.e., Araneae) and are likely higher quality prey for insectivores. Abundant orders common in the diets of insectivores, like Hymenoptera and Coleoptera, had high exoskeleton content and low protein content. We also found support for the ability of elements to predict macronutrients and found that metabolizable (i.e., exoskeleton removed) elemental content better predicted macronutrient content. A better understanding of arthropod nutrient content is critical for elucidating the role of spatial and temporal variation in prey communities in shaping the growth and survival of insectivores.
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Affiliation(s)
- Jacob T. Reeves
- Department of Integrative BiologyOklahoma State UniversityStillwaterOklahomaUSA
| | - Samuel D. Fuhlendorf
- Department of Natural Resource Ecology and ManagementOklahoma State UniversityStillwaterOklahomaUSA
| | - Craig A. Davis
- Department of Natural Resource Ecology and ManagementOklahoma State UniversityStillwaterOklahomaUSA
| | - Shawn M. Wilder
- Department of Integrative BiologyOklahoma State UniversityStillwaterOklahomaUSA
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16
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Summers TC, Ord TJ. The stabilising impact of natural selection on the allometry of sexual ornaments: Fish that escape locomotor constraints exhibit extravagant ornamentation. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13968] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Thomas C. Summers
- Evolution and Ecology Research Centre, and the School of Biological, Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
| | - Terry J. Ord
- Evolution and Ecology Research Centre, and the School of Biological, Earth and Environmental Sciences University of New South Wales Kensington NSW Australia
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Parrett JM, Slade EM, Knell RJ. Morph‐specific investment in testes mass in a trimorphic beetle,
Proagoderus watanabei. J Zool (1987) 2021. [DOI: 10.1111/jzo.12941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. M. Parrett
- Evolutionary Biology Group Faculty of Biology Adam Mickiewicz University Poznań Poland
- School of Biological and Behavioural Sciences Queen Mary, University of London London UK
| | - E. M. Slade
- Asian School of the Environment Nanyang Technological University Singapore City Singapore
| | - R. J. Knell
- School of Biological and Behavioural Sciences Queen Mary, University of London London UK
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Jenkins Shaw J, Voje KL. Horn scaling relationships in three species of Bledius Leach 1819 (Insecta: Coleoptera: Staphylinidae) show no indication of fitting non-linear allometric models. J NAT HIST 2021. [DOI: 10.1080/00222933.2021.1891315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Josh Jenkins Shaw
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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19
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Bertram SM, Yaremchuk DD, Reifer ML, Villarreal A, Muzzatti MJ, Kolluru GR. Tests of the positive and functional allometry hypotheses for sexually selected traits in the Jamaican field cricket. Behav Processes 2021; 188:104413. [PMID: 33957236 DOI: 10.1016/j.beproc.2021.104413] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 11/19/2022]
Abstract
Sexually selected traits, including threat signals, have been shown to scale steeply positively with body size because their exaggeration maximizes honest signalling. However, the functional allometry hypothesis makes the opposite prediction for some weapons: because the biomechanics of force applied in their use may favor relatively smaller size, sexually selected weapons may exhibit negative allometry. Tests of these ideas in insects have largely focused on holometabolous species, whose adult body size is entirely dependent on nutrients acquired during the larval stage. In contrast, hemimetabolous insects may exhibit different patterns of allometry development because they forage throughout development, between successive moults. Here, we tested complementary and competing predictions made by the positive and functional allometry hypotheses, regarding intrasexually selected trait allometry in a hemimetabolous insect, the Jamaican field cricket (Gryllus assimilis). As expected, head width (a dominance and/or combat trait) was more positively allometric than non-sexually selected traits. In contrast, and consistent with the functional allometry hypothesis, mouthparts (weapons) were either isometric or negatively allometric. We also tested whether trait allometry responded to rearing diet by raising males on either a high protein diet or a high carbohydrate diet; we predicted stronger positive allometry under the high protein diet. However, diet did not influence allometry in the predicted manner. Overall, our results support the functional allometry hypothesis regarding sexually selected trait allometry and raise intriguing possibilities for integrating these ideas with recent paradigms for classifying intrasexually selected traits.
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Affiliation(s)
- Susan M Bertram
- Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada.
| | - Danya D Yaremchuk
- Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
| | - Mykell L Reifer
- Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
| | - Amy Villarreal
- Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
| | - Matthew J Muzzatti
- Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, Canada
| | - Gita R Kolluru
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, California, 93407, United States
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Hernández ML, Acosta LE. Caracterización del dimorfismo sexual y reconocimiento de machos dimórficos en el complejo Discocyrtus prospicuus (Arachnida: Opiliones: Gonyleptidae): una aproximación desde la morfometría geométrica. REV MEX BIODIVERS 2021. [DOI: 10.22201/ib.20078706e.2021.92.3545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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21
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Is Allometric Variation in the Cephalic Horn on Male Rhinoceros Beetles Discontinuously Dimorphic? Evol Biol 2021. [DOI: 10.1007/s11692-021-09533-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Size variation does not act as insurance in bumble bees; instead, workers add weight in an unpredictable environment. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.10.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Del Sol JF, Hongo Y, Boisseau RP, Berman GH, Allen CE, Emlen DJ. Population differences in the strength of sexual selection match relative weapon size in the Japanese rhinoceros beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae)†. Evolution 2020; 75:394-413. [PMID: 33009663 DOI: 10.1111/evo.14101] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/07/2020] [Accepted: 09/07/2020] [Indexed: 12/21/2022]
Abstract
Exaggerated weapons of sexual selection often diverge more rapidly and dramatically than other body parts, suggesting that relevant agents of selection may be discernible in contemporary populations. We examined the ecology, reproductive behavior, and strength of sexual selection on horn length in five recently diverged rhinoceros beetle (Trypoxylus dichotomus) populations that differ in relative horn size. Males with longer horns were better at winning fights in all locations, but the link between winning fights and mating success differed such that selection favored large males with long horns at the two long-horned populations, but was relaxed or nonexistent at the populations with relatively shorter horns. Observations of local habitat conditions and breeding ecology point to shifts in the relative abundance of feeding territories as the most likely cause of population differences in selection on male weapon size in this species. Comparisons of ecological conditions and selection strength across populations offer critical first steps toward meaningfully linking mating system dynamics, selection patterns, and diversity in sexually selected traits.
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Affiliation(s)
- Jillian F Del Sol
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Yoshihito Hongo
- Department of Life Sciences, Ritsumeikan University, Kyoto, 603-8577, Japan
| | - Romain P Boisseau
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Gabriella H Berman
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Cerisse E Allen
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Douglas J Emlen
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
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Tidière M, Gaillard J, Garel M, Lemaître J, Toïgo C, Pélabon C. Variation in the ontogenetic allometry of horn length in bovids along a body mass continuum. Ecol Evol 2020; 10:4104-4114. [PMID: 32489634 PMCID: PMC7244813 DOI: 10.1002/ece3.6181] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/04/2020] [Accepted: 02/24/2020] [Indexed: 12/18/2022] Open
Abstract
Allometric relationships describe the proportional covariation between morphological, physiological, or life-history traits and the size of the organisms. Evolutionary allometries estimated among species are expected to result from species differences in ontogenetic allometry, but it remains uncertain whether ontogenetic allometric parameters and particularly the ontogenetic slope can evolve. In bovids, the nonlinear evolutionary allometry between horn length and body mass in males suggests systematic changes in ontogenetic allometry with increasing species body mass. To test this hypothesis, we estimated ontogenetic allometry between horn length and body mass in males and females of 19 bovid species ranging from ca. 5 to 700 kg. Ontogenetic allometry changed systematically with species body mass from steep ontogenetic allometries over a short period of horn growth in small species to shallow allometry with the growth period of horns matching the period of body mass increase in the largest species. Intermediate species displayed steep allometry over long period of horn growth. Females tended to display shallower ontogenetic allometry with longer horn growth compared to males, but these differences were weak and highly variable. These findings show that ontogenetic allometric slope evolved across species possibly as a response to size-related changes in the selection pressures acting on horn length and body mass.
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Affiliation(s)
- Morgane Tidière
- Department of BiologyCentre for Biodiversity DynamicsNTNUNorwegian University of Science and TechnologyTrondheimNorway
| | - Jean‐Michel Gaillard
- Laboratoire de Biométrie et Biologie Evolutive - UMR5558 - CNRSUniversité Claude Bernard Lyon 1Université de LyonVilleurbanneFrance
| | | | - Jean‐François Lemaître
- Laboratoire de Biométrie et Biologie Evolutive - UMR5558 - CNRSUniversité Claude Bernard Lyon 1Université de LyonVilleurbanneFrance
| | - Carole Toïgo
- Office Français pour la BiodiversitéGièresFrance
| | - Christophe Pélabon
- Department of BiologyCentre for Biodiversity DynamicsNTNUNorwegian University of Science and TechnologyTrondheimNorway
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Powell EC, Painting CJ, Hickey AJ, Holwell GI. Defining an intrasexual male weapon polymorphism in a New Zealand harvestman (Opiliones: Neopilionidae) using traditional and geometric morphometrics. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abstract
In many species, competition for mates has led to exaggerated male sexually-selected traits. Sexually-selected male weapons are used in male-male combat and include structures like horns, antlers and enlarged teeth. Weapons often vary intraspecifically in size, resulting in either a continuum of weapon sizes or in discrete male polymorphisms. More rarely, complex weapon polymorphisms can also include variation in weapon shape; however, these are difficult to quantify. Here we first use traditional linear morphometrics to describe a weapon trimorphism in the endemic New Zealand harvestman, Forsteropsalis pureoraTaylor, 2013. We identified three male morphs: a small-bodied gamma male with reduced chelicera, a large-bodied beta male with long, slender chelicerae, and a large-bodied alpha male with shorter, but very broad, robust chelicerae. Chelicera length alone failed to fully capture the variation in weapon investment. Using geometric morphometrics, we show that alpha males are different in weapon shape, whereas beta and gamma males have similar weapon shape, but vary in their body size and chelicera length. Additionally, we describe how the chelicerae function during male-male combat from observations of contests. This work demonstrates how combining linear and geometric morphometrics can help to elucidate complex polymorphism.
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Affiliation(s)
- Erin C Powell
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Christina J Painting
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Anthony J Hickey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Gregory I Holwell
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Toubiana W, Khila A. Fluctuating selection strength and intense male competition underlie variation and exaggeration of a water strider's male weapon. Proc Biol Sci 2020; 286:20182400. [PMID: 30991924 PMCID: PMC6501938 DOI: 10.1098/rspb.2018.2400] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Sexually selected traits can reach high degrees of phenotypic expression and variation under directional selection. A growing number of studies suggest that such selection can vary in space, time and form within and between populations. However, the impact of these fluctuations on sexual trait evolution is poorly understood. In the water strider Microvelia longipes, males display striking trait exaggeration and phenotypic variation manifested as extreme differences in the rear leg length. To study the origin and maintenance of this exaggerated trait, we conducted comparative behavioural, morphometric and reaction norm experiments in a selection of Microvelia species. We uncovered differences both in the mating behaviour and the degree of sexual dimorphism across these species. Interestingly, M. longipes evolved a specific mating behaviour where males compete for egg-laying sites, consisting of small floating objects, to intercept and copulate with gravid females. Through male–male competition assays, we demonstrated that male rear legs are used as weapons to dominate egg-laying sites and that intense competition is associated with the evolution of rear leg length exaggeration. Field observations revealed rapid fluctuation in M. longipes habitat stability and the abundance of egg-laying sites. Paternity tests using genetic markers demonstrated that small males could only fertilize about 5% of the eggs when egg-laying sites are limiting, whereas this proportion increased to about 20% when egg-laying sites become abundant. Furthermore, diet manipulation and artificial selection experiments also showed that the exaggerated leg length in M. longipes males is influenced by both genetic and nutritional factors. Collectively, our results highlight how fluctuation in the strength of directional sexual selection, through changes in the intensity of male competition, can drive the exaggeration and phenotypic variation in this weapon trait.
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Affiliation(s)
- William Toubiana
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5242 , Ecole Normale Supérieure de Lyon, 46, allée d'Italie, 69364 Lyon Cedex 07 , France
| | - Abderrahman Khila
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5242 , Ecole Normale Supérieure de Lyon, 46, allée d'Italie, 69364 Lyon Cedex 07 , France
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Graham ZA, Garde E, Heide-Jørgensen MP, Palaoro AV. The longer the better: evidence that narwhal tusks are sexually selected. Biol Lett 2020; 16:20190950. [PMID: 32183636 PMCID: PMC7115180 DOI: 10.1098/rsbl.2019.0950] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 02/24/2020] [Indexed: 01/14/2023] Open
Abstract
Once thought to be the magical horn of a unicorn, narwhal tusks are one of the most charismatic structures in biology. Despite years of speculation, little is known about the tusk's function, because narwhals spend most of their lives hidden underneath the Arctic ice. Some hypotheses propose that the tusk has sexual functions as a weapon or as a signal. By contrast, other hypotheses propose that the tusk functions as an environmental sensor. Since assessing the tusks function in nature is difficult, we can use the morphological relationships of tusk size with body size to understand this mysterious trait. To do so, we collected morphology data on 245 adult male narwhals over the course of 35 years. Based on the disproportional growth and large variation in tusk length we found, we provide the best evidence to date that narwhal tusks are indeed sexually selected. By combining our results on tusk scaling with known material properties of the tusk, we suggest that the narwhal tusk is a sexually selected signal that is used during male-male contests.
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Affiliation(s)
- Zackary A. Graham
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Eva Garde
- Greenland Institute of Natural Resources, Box 570, DK-3900 Nuuk, Greenland
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Allometry and Fighting Behaviour of a Dimorphic Stag Beetle Cyclommatus mniszechi (Coleoptera: Lucanidae). INSECTS 2020; 11:insects11020081. [PMID: 31979391 PMCID: PMC7074643 DOI: 10.3390/insects11020081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 11/30/2022]
Abstract
Male stag beetles (Coleoptera: Lucanidae) use their mandibles as weapons to compete for resources and reproduction. Mandible size in stag beetles can be associated with different behaviours and the outcome of male contests. We investigated the allometric relationship between mandible and body size in males of the stag beetle Cyclommatus mniszechi to uncover distinct morphs. The results divided male C. mniszechi into majors and minors with the switch point of mandible length at 14.01 mm. The allometric slope of mandibles was positive for both morphs but was steeper for the minors. We also characterised the fighting behaviour of the different morphs in size-matched contests using sequential analyses. Males matched each other’s behaviour in contests with many physical contacts, no injury and a progression from low towards high aggression and rare de-escalation. Major and minor males employed the same behavioural elements in contests, but major males were more likely to escalate directly into more aggressive phases and minor males tended to stay within phases. This finding suggests that major males may compete more aggressively than minor males in contests.
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30
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Dowdy NJ, Conner WE. Characteristics of tiger moth (Erebidae: Arctiinae) anti-bat sounds can be predicted from tymbal morphology. Front Zool 2019; 16:45. [PMID: 31827571 PMCID: PMC6902478 DOI: 10.1186/s12983-019-0345-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 11/29/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Acoustic signals are used by many animals to transmit information. Variation in the acoustic characteristics of these signals often covaries with morphology and can relay information about an individual's fitness, sex, species, and/or other characteristics important for both mating and defense. Tiger moths (Lepidoptera: Erebidae: Arctiinae) use modified cuticular plates called "tymbal organs" to produce ultrasonic clicks which can aposematically signal their toxicity, mimic the signals of other species, or, in some cases, disrupt bat echolocation. The morphology of the tymbal organs and the sounds they produce vary greatly between species, but it is unclear how the variation in morphology gives rise to the variation in acoustic characteristics. This is the first study to determine how the morphological features of tymbals can predict the acoustic characteristics of the signals they produce. RESULTS We show that the number of striations on the tymbal surface (historically known as "microtymbals") and, to a lesser extent, the ratio of the projected surface area of the tymbal to that of the thorax have a strong, positive correlation with the number of clicks a moth produces per unit time. We also found that some clades have significantly different regression coefficients, and thus the relationship between microtymbals and click rate is also dependent on the shared ancestry of different species. CONCLUSIONS Our predictive model allows the click rates of moths to be estimated using preserved material (e.g., from museums) in cases where live specimens are unavailable. This has the potential to greatly accelerate our understanding of the distribution of sound production and acoustic anti-bat strategies employed by tiger moths. Such knowledge will generate new insights into the evolutionary history of tiger moth anti-predator defenses on a global scale.
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Affiliation(s)
- Nicolas J. Dowdy
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina USA
- Invertebrate Zoology, Milwaukee Public Museum, 800 W. Wells Street, Milwaukee, WI USA
| | - William E. Conner
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina USA
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Rodríguez-Escobar FE, Carrillo-Muñoz AI, Serrano-Meneses MA. Seasonal variation in the allometry of wing pigmentation in adult males of the territorial damselfly Hetaerina vulnerata (Insecta Odonata). ETHOL ECOL EVOL 2019. [DOI: 10.1080/03949370.2019.1693432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Frida E. Rodríguez-Escobar
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Puebla, C.P. 72810, México
| | - Aldo I. Carrillo-Muñoz
- Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Carretera Tlaxcala-Puebla km 1.5, Tlaxcala, C.P. 90070, México
- Doctorado en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, México
| | - Martín A. Serrano-Meneses
- Departamento de Ciencias Químico-Biológicas, Universidad de las Américas Puebla, Puebla, C.P. 72810, México
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32
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Frankino WA, Bakota E, Dworkin I, Wilkinson GS, Wolf JB, Shingleton AW. Individual Cryptic Scaling Relationships and the Evolution of Animal Form. Integr Comp Biol 2019; 59:1411-1428. [PMID: 31364716 PMCID: PMC6863759 DOI: 10.1093/icb/icz135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Artificial selection offers a powerful tool for the exploration of how selection and development shape the evolution of morphological scaling relationships. An emerging approach models the expression and evolution of morphological scaling relationships as a function of variation among individuals in the developmental mechanisms that regulate trait growth. These models posit the existence of genotype-specific morphological scaling relationships that are unseen or "cryptic." Within-population allelic variation at growth-regulating loci determines how these individual cryptic scaling relationships are distributed, and exposure to environmental factors that affect growth determines the size phenotype expressed by each individual on their cryptic, genotype-specific scaling relationship. These models reveal that evolution of the intercept and slope of the population-level static allometry is determined, often in counterintuitive ways, largely by the shape of the distribution of these underlying individual-level scaling relationships. Here we review this modeling framework and present the wing-body size individual cryptic scaling relationships from a population of Drosophila melanogaster. To determine how these models might inform interpretation of published work on scaling relationship evolution, we review studies where artificial selection was applied to alter the parameters of population-level static allometries. Finally, motivated by our review, we outline areas in need of empirical work and describe a research program to address these topics; the approach includes describing the distribution of individual cryptic scaling relationships across populations and environments, empirical testing of the model's predictions, and determining the effects of environmental heterogeneity on realized trait distributions and how this affects allometry evolution.
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Affiliation(s)
- W Anthony Frankino
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - Eric Bakota
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - Ian Dworkin
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L9H 6X9
| | - Gerald S Wilkinson
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Jason B Wolf
- Milner Centre for Evolution and Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Alexander W Shingleton
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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Male Horn Lack of Allometry May be Tied to Food Relocation Behaviour in Lifting Dung Beetles (Coleoptera, Scarabaeidae, Eucraniini). INSECTS 2019; 10:insects10100359. [PMID: 31635392 PMCID: PMC6835258 DOI: 10.3390/insects10100359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/12/2019] [Accepted: 10/17/2019] [Indexed: 11/17/2022]
Abstract
The small dung beetle tribe Eucraniini includes extremely specialized species that have been defined as "lifters" according to their food relocation behaviour. They are characterized by the presence of well-developed expansions on the head and pronotum, which can be included in the large and varied group of horns, whose presence is usually related to complex reproductive tactics. In this study, two closely related species, Anomiopsoides cavifrons and A. heteroclyta, were examined employing traditional and geometric morphometrics to test whether the Eucraniini has polymorphic males that might exhibit different reproductive tactics, as in the sister tribe Phanaeini, for which a male trimorphism was demonstrated. If also present in Eucraniini polyphenism could be considered a plesiomorphy common to the two clades. The inter- and intraspecific shape variation and object symmetry of the head and the scaling relationships between body size and traits were evaluated. Marked interspecific and small intraspecific differences in shape variation, high symmetry, and similar isometric growth patterns were shown in both species. The hypothesis of male polymorphism in Anomiopsoides was thus rejected. Instead, the results supported the alternative hypothesis that Eucraniini lacks male polymorphism, perhaps due to functional constraints affecting the shape of the structures involved in their peculiar food relocating behaviour.
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Variation in an Extreme Weapon: Horn Performance Differences across Rhinoceros Beetle ( Trypoxylus dichotomus) Populations. INSECTS 2019; 10:insects10100346. [PMID: 31618906 PMCID: PMC6835817 DOI: 10.3390/insects10100346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 01/02/2023]
Abstract
Japanese rhinoceros beetle (Trypoxylus dichotomus) males have exaggerated head horns that they use as weapons in combat over reproductive opportunities. In these contests, there is an advantage to having a longer horn, and there seems to be little cost to horn exaggeration. However, populations vary in the amount of horn exaggeration across this widespread species. Here, we examine four populations and quantify scaling and functional morphology of the horn. We then measure force production by the horn system in a combat-relevant movement. We find that not only does horn length vary among populations, but allometry of lever mechanics and force production varies in a complex way. For instance, some beetle populations make relatively long horns, but exert relatively low forces. Other populations make shorter horns and produce higher forces during fights. We suggest that this performance variation could be associated with differences in the intensity or type of sexual selection across the species.
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Melin A, Krenn HW, Bowie RCK, Beale CM, Manning JC, Colville JF. The allometry of proboscis length in Melittidae (Hymenoptera: Apoidae) and an estimate of their foraging distance using museum collections. PLoS One 2019; 14:e0217839. [PMID: 31173614 PMCID: PMC6555519 DOI: 10.1371/journal.pone.0217839] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 05/20/2019] [Indexed: 12/03/2022] Open
Abstract
An appreciation of body size allometry is central for understanding insect pollination ecology. A recent model utilises allometric coefficients for five of the seven extant bee families (Apoidea: Anthophila) to include crucial but difficult-to-measure traits, such as proboscis length, in ecological and evolutionary studies. Melittidae were not included although they are important pollinators in South Africa where they comprise an especially rich and morphologically diverse fauna. We measured intertegular distance (correlated with body size) and proboscis length of 179 specimens of 11 species from three genera of Melittidae. With the inclusion of Melittidae, we tested the between family differences in the allometric scaling coefficients. AIC model selection was used to establish which factors provide the best estimate of proboscis length. We explored a hypothesis that has been proposed in the literature, but which has not been tested, whereby body and range sizes of bees are correlated with rainfall regions. We tested this by using body size measurements of 2109 museum specimens from 56 species of Melittidae and applied the model coefficients to estimate proboscis length and foraging distance. Our results from testing differences across bee families show that with the addition of Melittidae, we retained the overall pattern of significant differences in the scaling coefficient among Apoidea, with our model explaining 98% of the variance in species-level means for proboscis length. When testing the relationship between body size and rainfall region we found no relationship for South African Melittidae. Overall, this study has added allometric scaling coefficients for an important bee family and shown the applicability of using these coefficients when linked with museum specimens to test ecological hypothesis.
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Affiliation(s)
- Annalie Melin
- Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa
- Compton Herbarium, South African National Biodiversity Institute, Claremont, South Africa
| | - Harald W. Krenn
- Department of Integrative Zoology, University of Vienna, Faculty of Life Science, Vienna, Austria
| | - Rauri C. K. Bowie
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California—Berkeley, Berkeley, California, United States of America
- NRF Centre of Excellence at the Percy FitzPatrick Institute, University of Cape Town, Cape Town, South Africa
| | - Colin M. Beale
- Department of Biology, University of York, York, United Kingdom
| | - John C. Manning
- Compton Herbarium, South African National Biodiversity Institute, Claremont, South Africa
- Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, Scottsville, South Africa
| | - Jonathan F. Colville
- Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Claremont, Cape Town, South Africa
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Goczał J, Rossa R, Tofilski A. Intersexual and intrasexual patterns of horn size and shape variation in the European rhinoceros beetle: quantifying the shape of weapons. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Jakub Goczał
- Institute of Forest Ecosystem Protection, University of Agriculture in Krakow, Krakow, Poland
| | - Robert Rossa
- Institute of Forest Ecosystem Protection, University of Agriculture in Krakow, Krakow, Poland
| | - Adam Tofilski
- Department of Pomology and Apiculture, University of Agriculture in Krakow, Kraków, Poland
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Vesović N, Ivanović A, Ćurčić S. Sexual size and shape dimorphism in two ground beetle taxa, Carabus (Procrustes) coriaceus cerisyi and C. (Morphocarabus) kollari praecellens (Coleoptera: Carabidae) - A geometric morphometric approach. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 49:1-9. [PMID: 30710632 DOI: 10.1016/j.asd.2019.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/04/2019] [Accepted: 01/28/2019] [Indexed: 06/09/2023]
Abstract
We investigated morphometric variation in size and shape of the head, pronotum, and abdomen between the taxa and sexes of two ground beetles, Carabus coriaceus cerisyi Dejean, 1826 and C. kollari praecellens Palliardi, 1825. These two taxa differ in overall size, and both of them are characterized by significant sexual size dimorphism. In many taxa, allometry, the relationship between changes in shape and changes in size, can be a major component of intra- and interspecific variation in body shape. In the present study, we applied landmark-based geometric morphometrics to explore allometric and non-allometric components of shape variation between the taxa and more importantly between sexes within the taxa. We were able to show that the differences of shape between the taxa cannot be explained by allometric changes, as allometry explains only a small amount of total shape variation between the taxa, which was expected due to the fact that the taxa belong to separate subgenera. Between the sexes, on the other hand, allometry contributes largely to the variation, particularly in abdomen shape. However, the differences of head and pronotum shape between the sexes cannot be entirely explained in terms of allometric scaling. Our results indicate that allometry contributes largely to differences of body shape between the sexes, while differences between the taxa are influenced by other factors and processes.
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Affiliation(s)
- Nikola Vesović
- Institute of Zoology, University of Belgrade - Faculty of Biology, Studentski Trg 16, 11000 Belgrade, Serbia.
| | - Ana Ivanović
- Institute of Zoology, University of Belgrade - Faculty of Biology, Studentski Trg 16, 11000 Belgrade, Serbia.
| | - Srećko Ćurčić
- Institute of Zoology, University of Belgrade - Faculty of Biology, Studentski Trg 16, 11000 Belgrade, Serbia.
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38
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Facial masculinity does not appear to be a condition-dependent male ornament and does not reflect MHC heterozygosity in humans. Proc Natl Acad Sci U S A 2019; 116:1633-1638. [PMID: 30647112 DOI: 10.1073/pnas.1808659116] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent studies have called into question the idea that facial masculinity is a condition-dependent male ornament that indicates immunocompetence in humans. We add to this growing body of research by calculating an objective measure of facial masculinity/femininity using 3D images in a large sample (n = 1,233) of people of European ancestry. We show that facial masculinity is positively correlated with adult height in both males and females. However, facial masculinity scales with growth similarly in males and females, suggesting that facial masculinity is not exclusively a male ornament, as male ornaments are typically more sensitive to growth in males compared with females. Additionally, we measured immunocompetence via heterozygosity at the major histocompatibility complex (MHC), a widely-used genetic marker of immunity. We show that, while height is positively correlated with MHC heterozygosity, facial masculinity is not. Thus, facial masculinity does not reflect immunocompetence measured by MHC heterozygosity in humans. Overall, we find no support for the idea that facial masculinity is a condition-dependent male ornament that has evolved to indicate immunocompetence.
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Eberhard WG, Rodríguez RL, Huber BA, Speck B, Miller H, Buzatto BA, Machado G. Sexual Selection and Static Allometry: The Importance of Function. QUARTERLY REVIEW OF BIOLOGY 2018. [DOI: 10.1086/699410] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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40
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Kerman K, Roggero A, Rolando A, Palestrini C. Evidence for Male Horn Dimorphism and Related Pronotal Shape Variation in Copris lunaris (Linnaeus, 1758) (Coleoptera: Scarabaeidae, Coprini). INSECTS 2018; 9:insects9030108. [PMID: 30135396 PMCID: PMC6164466 DOI: 10.3390/insects9030108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/16/2018] [Accepted: 08/19/2018] [Indexed: 01/15/2023]
Abstract
Male horn dimorphism is a rather common phenomenon in dung beetles, where some adult individuals have well-developed head horns (i.e., major males), while others exhibit diminished horn length (i.e., minor males). We focused on horn dimorphism and associated head and pronotum shape variations in Copris lunaris. We examined the allometric relationship between horn length (i.e., cephalic and pronotal horns) and maximum pronotum width (as index of body size) by fitting linear and sigmoidal models for both sexes. We then asked whether head and pronotum shape variations, quantified using the geometric morphometric approach, contributed to this allometric pattern. We found that female cephalic and pronotal horn growth showed a typical isometric scaling with body size. Horn length in males, however, exhibited sigmoidal allometry, where a certain threshold in body size separated males into two distinct morphs as majors and minors. Interestingly, we highlighted the same allometric patterns (i.e., isometric vs. sigmoidal models) by scaling horn lengths with pronotum shape, making evident that male horn dimorphism is not only a matter of body size. Furthermore, the analysis of shape showed that the three morphs had similar heads, but different pronota, major males showing a more expanded, rounded pronotum than minor males and females. These morphological differences in C. lunaris can ultimately have important functional consequences in the ecology of this species, which should be explored in future work.
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Affiliation(s)
- Kaan Kerman
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, I-10123 Torino, Italy.
| | - Angela Roggero
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, I-10123 Torino, Italy.
| | - Antonio Rolando
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, I-10123 Torino, Italy.
| | - Claudia Palestrini
- Department of Life Sciences and Systems Biology, University of Torino, Via Accademia Albertina 13, I-10123 Torino, Italy.
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41
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Broeckhoven C, de Kock C, Hui C. Sexual dimorphism in the dermal armour of cordyline lizards (Squamata: Cordylinae). Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- C Broeckhoven
- Laboratory of Functional Morphology, Department of Biology, University of Antwerp, Universiteitsplein, Wilrijk, Belgium
- Theoretical Ecology Group, Department of Mathematical Sciences, Stellenbosch University, Private Bag, Matieland, Stellenbosch, South Africa
| | - C de Kock
- Department of Botany & Zoology, Stellenbosch University, Private Bag, Matieland, Stellenbosch, South Africa
| | - C Hui
- Theoretical Ecology Group, Department of Mathematical Sciences, Stellenbosch University, Private Bag, Matieland, Stellenbosch, South Africa
- Theoretical and Physical Biosciences, African Institute for Mathematical Sciences, Cape Town, South Africa
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42
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Colville JF, Picker MD, Cowling RM. Feeding ecology and sexual dimorphism in a speciose flower beetle clade (Hopliini: Scarabaeidae). PeerJ 2018; 6:e4632. [PMID: 29942673 PMCID: PMC6015485 DOI: 10.7717/peerj.4632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/23/2018] [Indexed: 01/18/2023] Open
Abstract
The relationship between feeding ecology and sexual dimorphism is examined in a speciose South African monkey beetle clade. We test whether feeding and mating at a fixed site (embedding guild) is associated with greater levels of sexual dimorphism and possibly sexual selection than species using unpredictable feeding resources (non-embedding guild). Sexual dimorphism was measured using a point scoring system for hind leg and colour across the two feeding guilds for >50% of the regional fauna. Quantification of hind leg dimorphism using a scoring system and allometric scaling were used to identify traits subject to sexual selection. Feeding guild had a significant effect on hind leg dimorphism, with embedders having high and non-embedders low scores. The sessile and defendable distribution of females on stable platform flowers may favour contests and associated hind leg weaponry. In contrast, degree of colour dimorphism between the sexes was not associated with any particular feeding guild, and may serve to reduce male conflict and combat. Embedder males had high proportions (∼76%) of species with positive allometric slopes for almost all hind leg traits. For male non-embedders, only ∼37% of species showed positive scaling relationships. Phylogenetic data, in conjunction with behavioural data on the function of leg weaponry and visual signalling among males is needed to better understand the link between sexual dimorphism and sexual selection in the radiation of the monkey beetles.
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Affiliation(s)
- Jonathan F. Colville
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
- Statistics in Ecology, Environment and Conservation, University of Cape Town, Rondebosch, South Africa
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Mike D. Picker
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Richard M. Cowling
- African Centre for Coastal Palaeoscience, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
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43
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Rossi de Gasperis S, Redolfi De Zan L, Romiti F, Hardersen S, Carpaneto GM. Sexual dimorphism and allometry of secondary sexual character in Morimus asper (Coleoptera: Cerambycidae). ZOOMORPHOLOGY 2017. [DOI: 10.1007/s00435-017-0380-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Petelo M, Swierk L. Trait allometries generate super-honesty in Anolis dewlaps and may underlie sexual dimorphism. Integr Zool 2017; 12:97-111. [PMID: 27605422 DOI: 10.1111/1749-4877.12238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Whether or not sexually selected traits consistently exhibit positive allometry (i.e. are disproportionately large in larger individuals) is an ongoing debate. Multiple models and exceptions to this rule suggest that the underlying drivers of sexual trait allometry are nuanced. Here, we compare allometries of sexual and non-sexual traits of a species (Anolis aquaticus) within a well-studied lizard genus to test the competing hypotheses that sexual traits are, or are not, defined by positive allometry. We further consider the relationships of trait functions, which are relatively well understood in the genus Anolis, and allometry to identify potential drivers of allometric patterns. In particular, we explore how trait allometries interact to influence total organism function and generate sexual dimorphism. We quantified size (of targeted traits) and color of a sexual signal (the dewlap) in Anolis aquaticus in the field. The dewlap conveyed information relevant to intra-sexual combat and exhibited positive allometry. Overall, our results suggest that using single-trait allometries as indicators of past selection provides only an incomplete understanding of trait evolution. Although the function of positive allometry in some individual sexual signals (e.g. those conveying "super-honest" information) may be straightforward, we illustrate how scaling relationships interact synergistically to influence the function of phenotypes and propose avenues for future research.
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Affiliation(s)
- Maria Petelo
- Department of Biology, University of Hawai'i at Mānoa, Honolulu, USA
| | - Lindsey Swierk
- Las Cruces Biological Station, Organization for Tropical Studies, San Vito, Coto Brus, Costa Rica
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45
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Kojima W, Lin CP. It takes two to tango: functional roles, sexual selection and allometry of multiple male weapons in the flower beetle Dicronocephalus wallichii bourgoini. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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46
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Perl CD, Rossoni S, Niven JE. Conservative whole-organ scaling contrasts with highly labile suborgan scaling differences among compound eyes of closely related Formica ants. Ecol Evol 2017; 7:1663-1673. [PMID: 28331577 PMCID: PMC5355196 DOI: 10.1002/ece3.2695] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022] Open
Abstract
Static allometries determine how organ size scales in relation to body mass. The extent to which these allometric relationships are free to evolve, and how they differ among closely related species, has been debated extensively and remains unclear; changes in intercept appear common, but changes in slope are far rarer. Here, we compare the scaling relationships that govern the structure of compound eyes of four closely related ant species from the genus Formica. Comparison among these species revealed changes in intercept but not slope in the allometric scaling relationships governing eye area, facet number, and mean facet diameter. Moreover, the scaling between facet diameter and number was conserved across all four species. In contrast, facet diameters from distinct regions of the compound eye differed in both intercept and slope within a single species and when comparing homologous regions among species. Thus, even when species are conservative in the scaling of whole organs, they can differ substantially in regional scaling within organs. This, at least partly, explains how species can produce organs that adhere to genus wide scaling relationships while still being able to invest differentially in particular regions of organs to produce specific features that match their ecology.
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Affiliation(s)
- Craig D Perl
- School of Life Sciences Centre for Computational Neuroscience and Robotics University of Sussex Falmer Brighton UK
| | - Sergio Rossoni
- School of Life Sciences Centre for Computational Neuroscience and Robotics University of Sussex Falmer Brighton UK; Present address: Department of Physiology, Development and Neuroscience University of Cambridge Downing Site, Downing Street Cambridge CB2 3EG UK
| | - Jeremy E Niven
- School of Life Sciences Centre for Computational Neuroscience and Robotics University of Sussex Falmer Brighton UK
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47
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Palaoro AV, Briffa M. Weaponry and defenses in fighting animals: how allometry can alter predictions from contest theory. Behav Ecol 2016. [DOI: 10.1093/beheco/arw163] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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