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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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André GI, Firman RC, Simmons LW. The effect of genital stimulation on competitive fertilization success in house mice. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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3
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Lilley MK, Ham JR, Miller MR, Kolodziej K, Hill HM. Investigation of lateralization of socio-sexual behavior in belugas (Delphinapterus leucas). Behav Processes 2022; 201:104718. [DOI: 10.1016/j.beproc.2022.104718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 06/15/2022] [Accepted: 07/27/2022] [Indexed: 11/02/2022]
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4
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Clear E, Grant RA, Carroll M, Brassey CA. A Review and Case Study of 3D Imaging Modalities for Female Amniote Reproductive Anatomy. Integr Comp Biol 2022; 62:icac027. [PMID: 35536568 PMCID: PMC10570564 DOI: 10.1093/icb/icac027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/20/2022] [Indexed: 11/13/2022] Open
Abstract
Recent advances in non-invasive imaging methods have revitalised the field of comparative anatomy, and reproductive anatomy has been no exception. The reproductive systems of female amniotes present specific challenges, namely their often internal "hidden" anatomy. Quantifying female reproductive systems is crucial to recognising reproductive pathologies, monitoring menstrual cycles, and understanding copulatory mechanics. Here we conduct a review of the application of non-invasive imaging techniques to female amniote reproductive anatomy. We introduce the commonly used imaging modalities of computed tomography (CT) and magnetic resonance imaging (MRI), highlighting their advantages and limitations when applied to female reproductive tissues, and make suggestions for future advances. We also include a case study of micro CT and MRI, along with their associated staining protocols, applied to cadavers of female adult stoats (Mustela erminea). In doing so, we will progress the discussion surrounding the imaging of female reproductive anatomy, whilst also impacting the fields of sexual selection research and comparative anatomy more broadly.
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Affiliation(s)
- Emma Clear
- Department of Natural Sciences, Manchester Metropolitan University, Chester St, Manchester M1 5GD, UK
- Williamson Park Zoo, Quernmore Road, Lancaster, Lancashire LA1 1UX, UK
| | - Robyn A Grant
- Department of Natural Sciences, Manchester Metropolitan University, Chester St, Manchester M1 5GD, UK
| | - Michael Carroll
- Department of Life Sciences, Manchester Metropolitan University, Chester St, Manchester M1 5GD, UK
| | - Charlotte A Brassey
- Department of Natural Sciences, Manchester Metropolitan University, Chester St, Manchester M1 5GD, UK
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5
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Greenwood JF, Granados GL, Secor SM, Todd BD, Showalter I, Hedrick BP, Brennan PLR. Divergent Genital Morphologies and Female-Male Covariation in Watersnakes. Integr Comp Biol 2022; 62:icac020. [PMID: 35512541 DOI: 10.1093/icb/icac020] [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: 11/14/2022] Open
Abstract
Genital evolution can be driven by diverse selective pressures. Across taxa we see evidence of covariation between males and females, as well as divergent genital morphologies between closely related species. Quantitative analyses of morphological changes in coevolving male and female genitalia have not yet been shown in vertebrates. This study uses 2D and 3D geometric morphometrics to quantitatively compare the complex shapes of vaginal pouches and hemipenes across three species of watersnakes (the sister taxa Nerodia fasciata, N. sipedon, and a close relative N. rhombifer) to address the relationship between genital morphology and divergence time in a system where sexual conflict may have driven sexually antagonistic coevolution of genital traits. Our pairwise comparisons of shape differences across species show that the sister species have male and female genitalia that are significantly different from each other, but more similar to each other than to N. rhombifer. We also determine that the main axes of shape variation are the same for males and females, with changes that relate to deeper bilobation of the vaginal pouch and hemipenes. In males, the protrusion of the region of spines at the base of the hemipene trades off with the degree of bilobation, suggesting amelioration of sexual conflict, perhaps driven by changes in the relative size of the entrance of the vaginal pouch that could have made spines less effective.
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Affiliation(s)
- J F Greenwood
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
| | - G Lara Granados
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
| | - S M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487
| | - B D Todd
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, Davis, CA 95616
| | - I Showalter
- Biology Department, University of Massachusetts-Amherst, Amherst, MA 01003
| | - B P Hedrick
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans LA 70012
| | - P L R Brennan
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075
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6
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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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OUP accepted manuscript. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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8
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Brennan PLR, Sterett M, DiBuono M, Lara Granados G, Klo K, Marsden R, Schleinig P, Tanner L, Purdy S. Intra-horn Penile Intromission in the Alpaca Vicugna pacos and Consequences to Genital Morphology. Integr Comp Biol 2021; 61:624-633. [PMID: 33970265 DOI: 10.1093/icb/icab050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Copulatory behavior and genital morphology interact to deliver sperm more effectively during mating, but the nature of this interaction has not been explored in depth in most vertebrates. Alpacas have unusually long copulations lasting 15-20 min, and a unique copulatory behavior, where the penis intromits all the way past the cervix, into the uterine horns. Here we describe the morphology of male and female genitalia and report unique morphological characteristics that may be associated with this unusual insemination mode. Vaginal shape is highly variable, and seemingly not associated with age or parity. The cranial vagina varies between bulbous and cylindrical, while the caudal vagina is typically narrower and always cylindrical. The cervix consists of a series of two to three spirals or rings, and it is often found in a relaxed state that may prevent damage caused by the cartilaginous penis tip as it pushes through the cervix to reach the uterine horns. The uterus and uterine horns have a complex shape with multiple constrictions. The cartilaginous penis tip has a sharp urethral process that may help to push against these constrictions. The diameter of the vaginal lumen is much greater than the diameter of the penis suggesting that there is little direct interaction between them, and that female vaginal shape is not under strong copulatory selection. In effect, the entire female reproductive tract of the female is interacting with the penis during copulation.
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Affiliation(s)
- Patricia L R Brennan
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Maya Sterett
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Mary DiBuono
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Genesis Lara Granados
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Kay Klo
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Rebecca Marsden
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Pearl Schleinig
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Louise Tanner
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Stephen Purdy
- North American Camelid Studies Program, Nunoa Project, Belchertown, MA 01007, USA
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Orbach DN, Brassey CA, Gardiner JD, Brennan PLR. 3D genital shape complexity in female marine mammals. Ecol Evol 2021; 11:3210-3218. [PMID: 33841778 PMCID: PMC8019040 DOI: 10.1002/ece3.7269] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/17/2020] [Accepted: 01/12/2021] [Indexed: 11/06/2022] Open
Abstract
Comparisons of 3D shapes have recently been applied to diverse anatomical structures using landmarking techniques. However, discerning evolutionary patterns can be challenging for structures lacking homologous landmarks. We used alpha shape analyses to quantify vaginal shape complexity in 40 marine mammal specimens including cetaceans, pinnipeds, and sirenians. We explored phylogenetic signal and the potential roles of natural and sexual selection on vaginal shape evolution. Complexity scores were consistent with qualitative observations. Cetaceans had a broad range of alpha complexities, while pinnipeds were comparatively simple and sirenians were complex. Intraspecific variation was found. Three-dimensional surface heat maps revealed that shape complexity was driven by invaginations and protrusions of the vaginal wall. Phylogenetic signal was weak and metrics of natural selection (relative neonate size) and sexual selection (relative testes size, sexual size dimorphism, and penis morphology) did not explain vaginal complexity patterns. Additional metrics, such as penile shape complexity, may yield interesting insights into marine mammal genital coevolution. We advocate for the use of alpha shapes to discern patterns of evolution that would otherwise not be possible in 3D anatomical structures lacking homologous landmarks.
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Affiliation(s)
- Dara N. Orbach
- Department of Life SciencesTexas A&M University‐ Corpus ChristiCorpus ChristiTXUSA
- Department of Biological SciencesMount Holyoke CollegeSouth HadleyMAUSA
| | - Charlotte A. Brassey
- School of Science and the EnvironmentManchester Metropolitan UniversityManchesterUK
| | - James D. Gardiner
- Department of Musculoskeletal and Ageing ScienceInstitute of Lifecourse and Medical SciencesUniversity of LiverpoolLiverpoolUK
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