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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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Farnworth B, Purdie S, Wehi PM, Painting CJ. Exaggerated mandibles are correlated with enhanced foraging efficacy in male Auckland tree wētā. Biol Lett 2023; 19:20230207. [PMID: 37964578 PMCID: PMC10646448 DOI: 10.1098/rsbl.2023.0207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023] Open
Abstract
Sexual selection has driven the evolution of weaponry for males to fight rivals to gain access to females. Although weapons are predicted to increase males' reproductive success, they are also expected to incur costs and may impair functional activities, including foraging. Using feeding assays, we tested whether the enlarged mandibles of Auckland tree wētā (Hemideina thoracica) impact feeding activity (the total volume of biomass consumed, bite rate, and number of foraging visits) and foraging behaviour (time spent moving, feeding, or stationary). We predicted that increased head capsule size in male wētā would hinder their foraging efficacy. However, we found that wētā with longer heads fed at a faster rate and spent less time foraging than wētā with smaller heads, regardless of sex. Contrary to expectations that weapons impede functional activities, our results demonstrate that exaggerated traits can improve feeding performance and may offer benefits other than increased mating success.
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Affiliation(s)
| | | | | | - Christina J. Painting
- Te Aka Mātuatua School of Science, University of Waikato, Hamilton 3240, New Zealand
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Parrett JM, Łukasiewicz A, Chmielewski S, Szubert-Kruszyńska A, Maurizio PL, Grieshop K, Radwan J. A sexually selected male weapon characterized by strong additive genetic variance and no evidence for sexually antagonistic polyphenic maintenance. Evolution 2023; 77:1289-1302. [PMID: 36848265 PMCID: PMC10234106 DOI: 10.1093/evolut/qpad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/12/2022] [Accepted: 02/24/2023] [Indexed: 03/01/2023]
Abstract
Sexual selection and sexual antagonism are important drivers of eco-evolutionary processes. The evolution of traits shaped by these processes depends on their genetic architecture, which remains poorly studied. Here, implementing a quantitative genetics approach using diallel crosses of the bulb mite, Rhizoglyphus robini, we investigated the genetic variance that underlies a sexually selected weapon that is dimorphic among males and female fecundity. Previous studies indicated that a negative genetic correlation between these two traits likely exists. We found male morph showed considerable additive genetic variance, which is unlikely to be explained solely by mutation-selection balance, indicating the likely presence of large-effect loci. However, a significant magnitude of inbreeding depression also indicates that morph expression is likely to be condition-dependent to some degree and that deleterious recessives can simultaneously contribute to morph expression. Female fecundity also showed a high degree of inbreeding depression, but the variance in female fecundity was mostly explained by epistatic effects, with very little contribution from additive effects. We found no significant genetic correlation, nor any evidence for dominance reversal, between male morph and female fecundity. The complex genetic architecture underlying male morph and female fecundity in this system has important implications for our understanding of the evolutionary interplay between purifying selection and sexually antagonistic selection.
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Affiliation(s)
- Jonathan M Parrett
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Aleksandra Łukasiewicz
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Sebastian Chmielewski
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | | | - Paul L Maurizio
- Department of Medicine, Section of Genetic Medicine, University of Chicago, Chicago, Illinois, United States
| | - Karl Grieshop
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Jacek Radwan
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
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Sulaiman MH, Mustaffa Z, Saari MM, Daniyal H, Mirjalili S. Evolutionary mating algorithm. Neural Comput Appl 2022. [DOI: 10.1007/s00521-022-07761-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Parrett JM, Chmielewski S, Aydogdu E, Łukasiewicz A, Rombauts S, Szubert-Kruszyńska A, Babik W, Konczal M, Radwan J. Genomic evidence that a sexually selected trait captures genome-wide variation and facilitates the purging of genetic load. Nat Ecol Evol 2022; 6:1330-1342. [DOI: 10.1038/s41559-022-01816-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/26/2022] [Indexed: 10/17/2022]
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Female remating decisions and mate choice benefits in the beetle Gnatocerus cornutus. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03161-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Kokko H. The stagnation paradox: the ever-improving but (more or less) stationary population fitness. Proc Biol Sci 2021; 288:20212145. [PMID: 34784767 PMCID: PMC8596016 DOI: 10.1098/rspb.2021.2145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fisher's fundamental theorem states that natural selection improves mean fitness. Fitness, in turn, is often equated with population growth. This leads to an absurd prediction that life evolves to ever-faster growth rates, yet no one seriously claims generally slower population growth rates in the Triassic compared with the present day. I review here, using non-technical language, how fitness can improve yet stay constant (stagnation paradox), and why an unambiguous measure of population fitness does not exist. Subfields use different terminology for aspects of the paradox, referring to stasis, cryptic evolution or the difficulty of choosing an appropriate fitness measure; known resolutions likewise use diverse terms from environmental feedback to density dependence and ‘evolutionary environmental deterioration’. The paradox vanishes when these concepts are understood, and adaptation can lead to declining reproductive output of a population when individuals can improve their fitness by exploiting conspecifics. This is particularly readily observable when males participate in a zero-sum game over paternity and population output depends more strongly on female than male fitness. Even so, the jury is still out regarding the effect of sexual conflict on population fitness. Finally, life-history theory and genetic studies of microevolutionary change could pay more attention to each other.
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Affiliation(s)
- Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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Polak M, Tomkins JL. Evolution: Natural selection, sexual selection, and the jaws of death. Curr Biol 2021; 31:R1092-R1095. [PMID: 34582819 DOI: 10.1016/j.cub.2021.07.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Traits that increase reproductive success in males can have negative fitness consequences in females. A new study shows that natural selection by a predator that targets males with larger secondary sexual traits drives an evolutionary increase in female fitness.
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Affiliation(s)
- Michal Polak
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.
| | - Joseph L Tomkins
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, WA, Australia
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