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Kamimura Y, Lee CY. Subcortical life, evolution of flattened body, and constrained mating posture in the earwig Platylabia major (Insecta: Dermaptera: "Anisolabididae"). PLoS One 2023; 18:e0293701. [PMID: 37917643 PMCID: PMC10621853 DOI: 10.1371/journal.pone.0293701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023] Open
Abstract
Many animals take advantage of the shaded, humid, and protected environments in subcortical spaces, i.e., thin spaces under the loosened bark of dead trees. Permanent inhabitants of subcortical spaces often show specialized morphologies, such as a miniaturized or dorsoventrally flattened body. However, the evolutionary consequences of these specialized morphologies on behavioral, ecological, and life-history traits have been little studied. We studied the mating biology and anatomy of Platylabia major (usually placed in the family Anisolabididae), which is an obligate inhabitant of subcortical spaces with a paper-like flattened body, and compared them with those of two thicker, spongiphorid earwigs, Nesogaster amoenus and Paralabellula curvicauda. Mating trials in various settings showed that Pl. major requires thin spaces sandwiched by two planes to accomplish genital coupling and insemination. In contrast, the thicker species, although also frequently found in subcortical spaces, could mate on a single horizontal plane due to the ability of the male to twist its abdomen through approximately 180°. Examination by micro-computed tomography and a reagent-based clearing technique revealed no substantive differences in the configuration of mid-abdominal musculature between the species. The dorsal and lateral muscles of Pl. major, which are almost parallel to the antero-posterior body axis for accommodation within the thin abdomen, seemed incapable of producing the power to twist the abdomen. The abdominal musculature conforms to a simple pattern in both male and female earwigs, which is repeated in each of the pregenital segments. We conclude that small differences in the range of motion of each abdominal segment can result in large differences in possible mating postures and positions. Surgical experiments also demonstrated that both right and left penises of Pl. major are competent and used for insemination with no lateral bias, as in most other earwigs with twin penises studied to date.
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Affiliation(s)
- Yoshitaka Kamimura
- Department of Biology, Keio University, Yokohama, Japan
- Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Penang, Malaysia
| | - Chow-Yang Lee
- Urban Entomology Laboratory, Vector Control Research Unit, School of Biological Sciences, Universiti Sains Malaysia, Gelugor, Penang, Malaysia
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van Gammeren S, Lang M, Rücklin M, Schilthuizen M. No evidence for asymmetric sperm deposition in a species with asymmetric male genitalia. PeerJ 2022; 10:e14225. [PMID: 36447515 PMCID: PMC9701498 DOI: 10.7717/peerj.14225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/21/2022] [Indexed: 11/25/2022] Open
Abstract
Background Asymmetric genitalia have repeatedly evolved in animals, yet the underlying causes for their evolution are mostly unknown. The fruit fly Drosophila pachea has asymmetric external genitalia and an asymmetric phallus with a right-sided phallotrema (opening for sperm release). The complex of female and male genitalia is asymmetrically twisted during copulation and males adopt a right-sided copulation posture on top of the female. We wished to investigate if asymmetric male genital morphology and a twisted gentitalia complex may be associated with differential allocation of sperm into female sperm storage organs. Methods We examined the internal complex of female and male reproductive organs by micro-computed tomography and synchrotron X-ray tomography before, during and after copulation. In addition, we monitored sperm aggregation states and timing of sperm transfer during copulation by premature interruption of copulation at different time-points. Results The asymmetric phallus is located at the most caudal end of the female abdomen during copulation. The female reproductive tract, in particular the oviduct, re-arranges during copulation. It is narrow in virgin females and forms a broad vesicle at 20 min after the start of copulation. Sperm transfer into female sperm storage organs (spermathecae) was only in a minority of examined copulation trials (13/64). Also, we found that sperm was mainly transferred early, at 2-4 min after the start of copulation. We did not detect a particular pattern of sperm allocation in the left or right spermathecae. Sperm adopted a granular or filamentous aggregation state in the female uterus and spermathecae, respectively. Discussion No evidence for asymmetric sperm deposition was identified that could be associated with asymmetric genital morphology or twisted complexing of genitalia. Male genital asymmetry may potentially have evolved as a consequence of a complex internal alignment of reproductive organs during copulation in order to optimize low sperm transfer rates.
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Affiliation(s)
| | - Michael Lang
- Université Paris Cité, CNRS - Institut Jacques Monod, Paris, France,Institut Diversité, Ecologie et Evolution du Vivant (IDEEV), Laboratoire Évolution, Génomes, Comportement et Écologie, CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France
| | | | - Menno Schilthuizen
- Naturalis Biodiversity Center, Leiden, The Netherlands,Institute for Biology, Leiden University, Leiden, Netherlands
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Functional Asymmetries Routing the Mating Behavior of the Rusty Grain Beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae). INSECTS 2022; 13:insects13080699. [PMID: 36005324 PMCID: PMC9409065 DOI: 10.3390/insects13080699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/22/2022] [Accepted: 07/27/2022] [Indexed: 12/04/2022]
Abstract
Simple Summary We evaluated the behavioral asymmetries of Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) males during courtship and mating with potential mates. The highest proportion of males showed left-biased approaches towards females, and turned 180° to their left. Right-biased males (i.e., approaching mates from the right and then turning 180°) were fewer than left-biased males. A low percentage of males approaching from the front and back side achieved successful mating. Left-biased-approaching males had a significantly shorter copula duration in comparison with other males. Left-biased males performed shorter copulation attempts and copula in comparison to right-biased males. This research contributes to understand the role of lateralization in the beetle family Laemophloeidae. Abstract The rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), is a serious secondary pest of stored and processed food commodities. In the present study, we investigated the lateralization of males during courtship and mating, attempting to understand if it can be linked with a high likelihood of successful copulation. Most males exhibited left-biased (41%) approaches towards females, and turned 180° to their left, with 37% mating success. Right-biased males (i.e., approaching from the right and then turning 180°) were fewer than left-biased ones; 26% out of 34% managed to copulate with females. Only 9% out of 13% and 7% out of 11% of the back side- and front side-approaching males succeeded in mating, respectively. Directional asymmetries in approaching a potential mate, as well as the laterality of side-biased turning 180°, significantly affected male copulation success, with left-biased males achieving higher mating success if compared to right-biased males. Copula duration was significantly lower for left-biased-approaching males (1668.0 s) over the others (i.e., 1808.1, 1767.9 and 1746.9 for right-biased, front and back side-males, respectively). Left-biased males performed shorter copulation attempts and copula compared to right-biased males. Overall, our study adds basic knowledge to the lateralized behavioral displays during courtship and copula of C. ferrugineus.
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Torres-Dowdall J, Rometsch SJ, Velasco JR, Aguilera G, Kautt AF, Goyenola G, Petry AC, Deprá GC, da Graça WJ, Meyer A. Genetic assimilation and the evolution of direction of genital asymmetry in anablepid fishes. Proc Biol Sci 2022; 289:20220266. [PMID: 35538779 PMCID: PMC9091857 DOI: 10.1098/rspb.2022.0266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Phylogenetic comparative studies suggest that the direction of deviation from bilateral symmetry (sidedness) might evolve through genetic assimilation; however, the changes in sidedness inheritance remain largely unknown. We investigated the evolution of genital asymmetry in fish of the family Anablepidae, in which males' intromittent organ (the gonopodium, a modified anal fin) bends asymmetrically to the left or the right. In most species, males show a 1 : 1 ratio of left-to-right-sided gonopodia. However, we found that in three species left-sided males are significantly more abundant than right-sided ones. We mapped sidedness onto a new molecular phylogeny, finding that this left-sided bias likely evolved independently three times. Our breeding experiment in a species with an excess of left-sided males showed that sires produced more left-sided offspring independently of their own sidedness. We propose that sidedness might be inherited as a threshold trait, with different thresholds across species. This resolves the apparent paradox that, while there is evidence for the evolution of sidedness, commonly there is a lack of support for its heritability and no response to artificial selection. Focusing on the heritability of the left : right ratio of offspring, rather than on individual sidedness, is key for understanding how the direction of asymmetry becomes genetically assimilated.
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Affiliation(s)
- Julián Torres-Dowdall
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Sina J. Rometsch
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Jacobo Reyes Velasco
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Gastón Aguilera
- Unidad Ejecutora Lillo (CONICET), Fundación Miguel Lillo, Tucumán, Argentina
| | - Andreas F. Kautt
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Guillermo Goyenola
- Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional del Este, Universidad de la República, Uruguay
| | - Ana C. Petry
- Instituto de Biodiversidade e Sustentabilidade, Universidade Federal do Rio de Janeiro, Macaé, Brazil
| | - Gabriel C. Deprá
- Departamento de Biologia, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Centro de Ciências Biológicas, Universidade Estadual de Maringá, Maringá, Brazil
| | - Weferson J. da Graça
- Departamento de Biologia, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Centro de Ciências Biológicas, Universidade Estadual de Maringá, Maringá, Brazil
| | - Axel Meyer
- Department of Biology, Zoology and Evolutionary Biology, University of Konstanz, 78457 Konstanz, Germany
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Karthik CM, Kamimura Y, Kalleshwaraswamy CM. A new species of Diplatys (Insecta, Dermaptera, Diplatyidae) earwig from the Western Ghats of India. Zookeys 2022; 1088:53-64. [PMID: 35437370 PMCID: PMC8922309 DOI: 10.3897/zookeys.1088.79416] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/15/2022] [Indexed: 11/21/2022] Open
Abstract
To explore diversity of earwigs (Dermaptera) in different agricultural ecosystems of South India, an extensive taxonomic survey was conducted in 2020 during which an undescribed species of Diplatys was collected. Twenty-one species of the genus Diplatys (Diplatyidae, Diplatyinae) have been reported to date from India, of which six species are known from Karnataka, South India. Based on a male specimen collected from a sugarcane field in Karnataka, a new species, Diplatyssahyadriensissp. nov., is described as the twenty-second species of this genus from India. A revised key to the males of Diplatys species from India and Sri Lanka is provided. This new record adds to the known species diversity in the Sahyadri Ranges of the Western Ghats in Shivamogga District, Karnataka, part of the Southern Plateau and Hills agro-climatic region of India.
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Kreuz J, Eberhard MJB. Asymmetry of the male internal reproductive organs in Mantophasmatodea. BMC ZOOL 2022; 7:4. [PMID: 37170166 PMCID: PMC10127319 DOI: 10.1186/s40850-021-00105-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 12/17/2021] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Asymmetries are a widespread phenomenon in otherwise bilaterally symmetric organisms, and investigation of asymmetric structures can help us gather insights into fundamental evolutionary processes such as the selection for morphological novelties caused by behavioural changes. In insects, asymmetric genitalia have evolved in almost every order, and usually it’s the sclerotized parts and most conspicuous male phallic organs that are known to exhibit asymmetries. While external copulatory organs in insects have often been subject to investigations concerning asymmetries and the evolution thereof, internal reproductive structures have received far less attention. Here we describe the internal and external male genitalia in three species of Austrophasmatidae, Mantophasmatodea, using μ-CT imaging and light microscopy. Mantophasmatodea is the most recently discovered insect order, and with 21 species described to date, it is among the smallest insect orders currently known.
Results
We confirm that male heelwalkers exhibit asymmetries in the external genitalia and associated structures, represented by asymmetric phallic lobes and cerci. Moreover, we found an extreme asymmetry within the internal male genitalia: in all adult males investigated (N = 5), the seminal vesicle, a dilatation of the vas deferens, was only developed on the right side of the male while missing on the left side.
Conclusion
The false-male-above mating position exhibited by Mantophasmatodea and especially the long copulation duration of ca. 3 days might select for this unusual absence asymmetry of the left seminal vesicle. If this holds true for all heelwalker species, this absence asymmetry constitutes another autapomorphy for Austrophasmatidae or even the insect order Mantophasmatodea.
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Kamimura Y, Matsumura Y, Yang CCS, Gorb SN. Random or handedness? Use of laterally paired penises in Nala earwigs (Insecta: Dermaptera: Labiduridae). Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Animals can show bias in their use of laterally paired organs that do not have any conspicuous anatomical differentiation between the right and left organs. Like right handedness in humans, males of the giant earwig Labidura riparia (Labiduridae: Labidurinae) preferentially (~90%) use the right one of their laterally paired penises for copulation. To elucidate the evolutionary origin of this lateralization, patterns of penis use were examined for the related species of the genus Nala (Labiduridae: Nalinae). In multiple populations and broods of both Nala lividipes and Nala nepalensis, males that were ready to use the right or left penis were equally frequent, providing a striking contrast to Labidura. Surgical ablation of one of the two penises revealed that both penises are functionally competent in N. lividipes. Nevertheless, each male almost consistently used only one of the paired penises, either the right or the left one. Changes in penis use were estimated to occur only once per 64–143 days per male. The present study is the first report of individual-level lateralization for animal genitalia that do not show any conspicuous anatomical differentiation between the right and left organs. Possible advantages of lateralization are discussed in relationship to co-evolution of the genitalia between the sexes.
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Affiliation(s)
| | - Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1–9, D-24118 Kiel, Germany
| | | | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1–9, D-24118 Kiel, Germany
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Orbach DN, Brennan PLR, Hedrick BP, Keener W, Webber MA, Mesnick SL. Asymmetric and Spiraled Genitalia Coevolve with Unique Lateralized Mating Behavior. Sci Rep 2020; 10:3257. [PMID: 32094449 PMCID: PMC7039966 DOI: 10.1038/s41598-020-60287-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/10/2020] [Indexed: 02/04/2023] Open
Abstract
Asymmetric genitalia and lateralized mating behaviors occur in several taxa, yet whether asymmetric morphology in one sex correlates or coevolves with lateralized mating behavior in the other sex remains largely unexplored. While lateralized mating behaviors are taxonomically widespread, among mammals they are only known in the harbor porpoise (Phocoena phocoena). Males attempt copulation by approaching a female exclusively on her left side. To understand if this unusual lateralized behavior may have coevolved with genital morphology, we quantified the shape of female and male harbor porpoise reproductive tracts using 2D geometric morphometrics and 3D models of the vaginal lumen and inflated distal penis. We found that the vaginas varied individually in shape and that the vaginas demonstrated both significant directional and fluctuating asymmetry. This asymmetry resulted from complex 3D spirals and vaginal folds with deep recesses, which may curtail the depth or direction of penile penetration and/or semen movement. The asymmetric shapes of the vaginal lumen and penis tip were both left-canted with similar angular bends that mirrored one another and correspond with the left lateral mating approach. We suggest that the reproductive anatomy of both sexes and their lateral mating behavior coevolved.
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Affiliation(s)
- Dara N Orbach
- Texas A&M University- Corpus Christi, Department of Life Sciences, 6300 Ocean Dr., Corpus Christi, Texas, 78412, USA. .,Mount Holyoke College, Department of Biological Sciences, 50 College Street, South Hadley, Massachusetts, 01075, USA.
| | - Patricia L R Brennan
- Mount Holyoke College, Department of Biological Sciences, 50 College Street, South Hadley, Massachusetts, 01075, USA
| | - Brandon P Hedrick
- Louisiana State University Health Sciences Center, Department of Cell Biology and Anatomy, 1901 Perdido Street, New Orleans, LA, 70112, USA.,University of Oxford, Department of Earth Sciences, South Parks Road, Oxford, OX1 3AN, UK
| | - William Keener
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, California, 94965, USA
| | - Marc A Webber
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, California, 94965, USA
| | - Sarah L Mesnick
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, California, 92037, USA
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