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A Brief Natural History of the Orgasm Thierry Lodé A brief natural history of the orgasm Thierry Lodé To cite this version: Thierry Lodé. A brief natural history of the orgasm. Frontiers in Life Science , Taylor and Francis, 2020, 13 (1), pp.34-44. 10.1080/21553769.2019.1664642. hal-02285727 HAL Id: hal-02285727 https://hal-univ-rennes1.archives-ouvertes.fr/hal-02285727 Submitted on 13 Sep 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Frontiers in Life Science ISSN: 2155-3769 (Print) 2155-3777 (Online) Journal homepage: https://www.tandfonline.com/loi/tfls20 A brief natural history of the orgasm Thierry Lodé To cite this article: Thierry Lodé (2020) A brief natural history of the orgasm, Frontiers in Life Science, 13:1, 34-44 To link to this article: https://doi.org/10.1080/21553769.2019.1664642 © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group Published online: 12 Sep 2019. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tfls20 FRONTIERS IN LIFE SCIENCE 2019, VOL. 13, NO. 1, 34–44 https://doi.org/10.1080/21553769.2019.1664642 PERSPECTIVE A brief natural history of the orgasm Thierry Lodé Laboratoire d’Éthologie Animale et Humaine EthoS–UMR-CNRS 6552, Université de Rennes 1, Rennes, France ABSTRACT ARTICLE HISTORY Why the sexual climax, in humans, results in a pleasurable experience remains an important biolog- Received 29 April 2019 ical question. Analysis of evolutionary traits in numerous Vertebrates suggests that orgasm evolved Accepted 27 August 2019 through three phylogenetic stages during the transition from external to internal fertilization and KEYWORDS viviparity. First, orgasm is directly dependent on ejaculation in males and the expulsion of fluids Orgasm; ovarian fluids; mate from the ovarian and urethral glands (Skene’s) in females. I propose that sexual orgasm could come choice; post-copulatory from the primitive reflex of discharging gametes to ensure reproduction. Thus, the understanding selection; sexual conflict; of orgasm should not be reduced to a penis- or a clitoris-centred paradigm. Secondly, orgasm has unrelated males evolved to stimulate sexual activity because the evolutionary transition from external fertilization to internal fertilization has been accompanied in numerous species with a lessening in reproductive rates. Because sexual activity encourages reproduction, it can be argued that orgasm has evolved to increase sexual activity, particularly in viviparous species with low reproductive rates. Third, internal fertilization in the genital tract of females weakens the visibility of the putative success of fertiliza- tion. Female sexual fluids and proteins can bias fertilization in favour of preferred males. Because orgasm could promote a better choice of partner, I argue that female orgasm may have evolved as a post-copulatory selection tactic by which females can increase their control of mates. Introduction blood pressure, increased heart rate, rhythmic respi- Why the sexual climax, in humans, leads to the experi- ratory pattern, involuntary body movements and, in ence of pleasure remains an important biological ques- females, by spontaneous colour changes of the labia tion.Whilethemalecannottransfergameteswith- minora which engorge to twice their size, and by out experiencing an orgasm, in the human species, vaginal and anal spasms (Masters and Johnson 1966; the female orgasm seems completely decoupled from Berman et al. 1999). The orgasm is directed by the reproduction (Cabanac 1971;Hrdy1996;Wallenand autonomic nervous system and the spinal cord but Lloyd 2008). Although orgasm could result from the activates numerous cortical zones through the vagus point that individuals with an orgasm are more suc- nerves mediation (Komisaruk et al. 2004). cessful, Wheatley and Puts (2015) argued that there is Although the definition of orgasm is rather uncer- actually little evidence to suggest that female orgasm tain, Bancroft (2005) described it as ‘a state motivated canpromoteabetterreproduction.Iforgasmhada toward the experience of sexual pleasure’. In males, selective role, then it is difficult to understand why it is associated with ejaculation and rhythmic muscle females show such variability in their ability to reach contractions of the perineal muscles, in females, with a climax. Analysing the evolutionary history of the clitoral retraction, rhythmic muscle contractions of the sexual climax from its phylogenetic origin, we can perineum and vagina. Orgasm also releases some neu- draw some new conclusions that can shed light on the ropeptides, dopamine, oxytocin and prolactin, which function of orgasm. cause a deep sense of well-being. Here, orgasm is Indeed, orgasm could only be regarded as a direct defined as the culmination of sexual arousal activating selective trait if individuals with this evolutionary trait the reward circuit. The increase in dopamine, oxy- have the best reproduction. Associated with ejacula- tocin and prolactin concentration can, therefore, be tion in males, orgasm is characterized by changes in considered as a signal of sexual arousal. All mammals CONTACT Thierry Lodé [email protected] Laboratoire d’Éthologie Animale et Humaine EthoS–UMR-CNRS 6552, Université de Rennes 1, 35042 Rennes, France © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. FRONTIERS IN LIFE SCIENCE 35 have the physiological capacity for orgasm (Fox and Puts 2015)sincefemaleorgasmsdonotappearto Fox 1971) and numerous vertebrates are known to have an active role in sperm transport during coitus experience orgasm-like states such as primates i.e. (Levin 2011). Nonetheless, cervical excitations pro- bonobo, chimpanzee, gorilla, orangutan, proboscis duce contractions of the oviduct and fallopian tubes monkey, macaques (Chevalier-Skolnikoff 1974;Allen (Komisaruk et al. 2004), probably via prostaglandins and Lemon 1981; Troisi and Carosi 1998;Murai2006; and are essential for sperm transport and fertiliza- de Waal 2011; Grueter and Stoinski 2016), carnivores tion (Adler 1969;AdlerandZoloth1970; Wildt et al. and rodents (Adler 1969;HeebandYahr1996;Coolen 1998). et al. 1997;Kollack-WalkerandNewman1997;Tenk The second theory claims that female orgasm has et al. 2009;PavlicevandWagner2016), birds and rep- no selective role and must be understood as a simple tiles (Cabanac 1971; Winterbottom et al. 1999;Balland by-product of ontogenesis since the embryonic devel- Balthazart 2011)andfishes(PeterssonandJarvi2001). opmentofthemalepenisandfemaleclitorisremains It has even been demonstrated that ejaculation pro- very comparable (Symons 1979;Gould1987;Wallen voked by the activation of Crz-expressing neurons is and Lloyd 2008). rewarding to male flies (Zer-Krispil et al. 2018). Thus, orgasm seems a critical component of reproductive Phylogeny of the orgasm process for many species (Balcombe 2009). There are two main theories that provide an expla- Nevertheless,itseemsquiterelevanttoestimatethe nation for the manifestation of orgasm. It has been role of orgasm by analysing how orgasm phyloge- firstly hypothesized that orgasm would favour the per- netically developed during the evolution of sexual sistence of bonds to ensure the best care for the off- behaviour. Analysis of evolutionary traits suggests that spring (Alcock 1987) or serve as a secondary rein- orgasm evolved through three phylogenetic stages dur- forcement linking sexual behaviours and partner affil- ing the transition from external to internal fertilization iation (Prause 2011;Fleischman2016). However, in and viviparity. many species, the male provides virtually no care to First, because the orgasm is also associated with the young, which reduces the interest in this hypothe- ejaculation in males and with orgasmic expulsions sis. Moreover, the strengthening of the couple’s bonds from ovarian and urethral glands in females, I rea- is clearly refuted by the Coolidge effect (Brown 1974), soned that the sexual orgasm could originate from which leads many males, and to a lesser extent some the ancestral reflex of gametes release in both sexes. females (Lester and Gorzalka 1988), to increase sexual Sex has been found to be the most common repro- activity by adopting a greater diversity of partners. In ductivemodeamongeukaryotes.Originallybasedon monkeys, females that mated with high-ranking males meiosis, it has been hypothesized that sex could come showed the highest frequency of orgasms (Zumpe from very archaic interactions among ‘libertine bub- and Michael 1968; Chevalier-Skolnikoff 1974), sug- bles’, i.e. practising horizontal gene exchanges (see gesting a role in partner preference. Finally, among Lodé
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