因此，能够转而进行无性生殖并将种群数量提高到临界水平以上的雌性，可能正是拯救物种免于灭绝的关键。就锯鳐而言，保护工作者确实看到了一些种群复苏的迹象，这可能要归功于这些在性生活方面创新的孤雌生殖雌性。
在这种乐观的前景下，仅存的问题来自我们人类。我写这本书的时候，仿佛看到了将要到来的世界末日。我们正处于全球疾病大流行的控制之下，大火正在摧毁亚马孙雨林和澳大利亚，前所未有的风暴正在席卷美洲、亚洲和欧洲。气候变化是非常真实的，并且在某些地方极为迅速地改变着地球的环境，以至于即使是个体数量充足的有性生殖物种也来不及适应。如果我们要停止对这个星球的猖獗破坏并让生态系统恢复，人类就需要做出根本性的改变（无论是个体的还是集体的），而且要快。
不需要借助花哨的数学模型就可以证明，无论采用何种繁殖方式，一个物种如果没有可以生存的栖息地，就都注定要灭亡。孤雌生殖是仅适用于特定物种的安全网，而且只有雌性才有无性生殖能力。这些特殊的雌性可能会变得越来越重要。如果我们继续走在战争和毁灭之路上，未来肯定是属于雌性的：只有蛭形轮虫会屹立不倒。
目前唯一未发现自然条件下无性生殖行为的主要脊椎动物类群就是哺乳动物。研究者在实验室条件下已经实现了哺乳动物的诱导孤雌生殖，但无论是在野外还是在圈养环境下，都还没有发现哺乳动物进行孤雌生殖的例子。哺乳动物的一些基本生物特征导致我们不太可能在自然界中发现任何哺乳动物进行孤雌生殖的现象。因此，看起来男人似乎（暂时）可以放心入睡了，而人类将继续依赖有性生殖。鉴于人类对地球环境的破坏和对资源的掠夺，这也许是个不错的消息。想到人类像蚜虫一样繁殖，真是个可怕的场景，而且肯定不是这个星球现在所需要的。
Jon Mooallem, ‘Can Animals Be Gay?’ in New York Times, 31 March 2010
Lindsay C. Young, Brenda J. Zaun and Eric A. Vanderwurf, ‘Successful Same-sex Pairing in Laysan Albatross’ in Biology Letters, 4: 4 (2008), pp. 323–5
Mooallem, ‘Can Animals Be Gay?’
Jack Falla, ‘Wayne Gretzky’ in The Top 100 NHL Players of All Time, ed. by Steve Dryden (McClelland and Stewart, 1998)
Inna Schneiderman, Orna Zagoory-Sharon and Ruth Feldman, ‘Oxytocin During the Initial Stages of Romantic Attachment: Relations to Couples’ Interactive Reciprocity’ in Psychoneuroendocrinology, 37: 8 (2012), pp. 1277–85
Elspeth Kenny, Tim R. Birkhead and Jonathan P. Green, ‘Allopreening in Birds is Associated with Parental Cooperation Over Ofspring Care and Stable Pair Bonds Across Years’ in Behavioural Ecology (ISBE, 2017), pp. 1142–8
J. D. Baker, C. L. Littman and D. W. Johnston, ‘Potential Efects of Sea Level Rise on the Terrestrial Habitats of Endangered and Endemic Megafauna in the North-western Hawaiian Islands’ in Endangered Species Research, 4 (2006), pp. 1–10
George L. Hunt and Molly Warner Hunt, ‘Female- Female Pairing in Western Gulls(Larus occidentalis ) in Southern California’ in Science, 196 (1977), pp. 1466–7
Ian C. T. Nisbet and Jeremy J. Hatch, ‘Consequences of a Female-biased Sex-ratio in a Socially Monogamous Bird: Female-female Pairs in the Roseate Tern Sterna dougallii ’in International Journal of Avian Science (1999)
壁虎是爬行纲蜥蜴目壁虎科动物的统称，哀鳞趾虎归属于壁虎科鳞趾虎属，因此既是壁虎，又属于蜥蜴的范畴。——编者注
Hadi Izadi, Katherine M. E. Stewart and Alexander Penlidis, ‘Role of Contact Electrification and Electrostatic Interactions in Gecko Adhesion’ in Journal of the Royal Society, Interface, 11: 98 (2014)
Elizabeth Landau, ‘Gecko Grippers Moving On Up’, NASA, 12 April 2015,https://www.nasa.gov/jpl/ gecko-grippers-moving-on-up
Kate L. Laskowski, Carolina Doran, David Bierbach, Jens Krause and Max Wolf, ‘Naturally Clonal Vertebrates Are an Untapped Resource in Ecology and Evolution Research’ in Nature Ecology & Evolution (2019), pp. 161–9
Graham Bell, The Masterpiece of Nature (University of California Press, 1982)
全雌性物种繁殖力翻倍的能力并没有逃过寻求利润最大化的农业科学家的眼睛。（Joan Roughgarden, Evolution’s Rainbow (University of California Press, 2004), p. 17）对于家鸡和火鸡这两种主要的家禽，人们已经经过选择性培育产生全雌性的品系。多莉羊是另一个例子。1996年，她由苏格兰一只羊的乳腺细胞克隆而来，以性感的多莉·帕顿女士的名字命名，并闻名全球。然而，创造她的背后原因鲜为人知，其实这反映了50年来人们试图通过消除有性生殖来增加农业哺乳动物产量的愿望。
18世纪著名的法国博物学家雷内·雷奥米尔计算出，在夏季，如果一只蚜虫的所有后代都存活下来，并按照法国军队的四人并排来排列，其阵线将延伸27 950英里，足以超过地球赤道的周长。说雷奥米尔对蚜虫非常着迷并不为过。这位狂热的昆虫学家在他的畅销书《昆虫史》中满怀热情地写到，尽管他花了很多时间寻找，但他无论如何都找不到一只雄性蚜虫，也没有找到一对正在进行“交配”的蚜虫。他甚至试图连续数天观察一只未交配过的雌性蚜虫，以便抓到她产卵前的交配行为，但失败了。随后，一位名叫查尔斯·博内的年轻科学家接手了这个实验。博内把一只未交配过的雌性蚜虫关在一个罐子里，从早上4点到晚上10点不分昼夜地观察了整整33天。他非常确信这只蚜虫没有交配过，但她产下了95只蚜虫。他对蚜虫的持续观察得到了回报。1740年，博内成为第一个反驳自然界中有性生殖普遍性，并宣称存在孤雌生殖的人。
Logan Chipkin, Peter Olofsson, Ryan C. Daileda and Ricardo B. R. Azevedo,‘Muller’s Ratchet in Asexual Populations Doomed to Extinction’, eLife, 13 Nov. 2018,https://doi.org/10.1101/448563
Malin Ah-King, ‘Queer Nature: Towards a Non-normative View on Biological Diversity’ in Body Claims, ed. by J. Bromseth, L. Folkmarson Käll and K. Mattsson (Centre for Gender Research, Uppsala University, 2009)
J. Maynard Smith, The Evolution of Sex (Cambridge University Press, 1978)
C. Boschetti, A. Carr, A. Crisp, I. Eyres, Y. Wang- Koh, E. Lubzens, T. G.Barraclough, G. Micklem and A. Tunnaclife, ‘Biochemical Diversification through Foreign Gene Expression in Bdelloid Rotifers’ in PLoS Genetics (2012)
水熊：又称缓步动物，是一类可以进入休眠、干燥状态的微小生物，在这种状态下可以承受极端高温、接近绝对零度的温度、有毒气体和极端辐射，甚至可以在真空的太空中幸存。即便如此，水熊也无法像蛭形轮虫一样承受500~1 000戈瑞剂量的辐射。
Maurine Neiman, Stephanie Meirmans and Patrick G. Meirmans, ‘What Can Asexual Lineage Age Tell Us about the Maintenance of Sex?’ in The Year in Evolutionary Biology (2009), vol. 1168, issue 1, pp. 185–200
Robert D. Denton, Ariadna E. Morales and H. Lisle Gibbs, ‘Genomespecific Histories of Divergence and Introgression Between an Allopolyploid Unisexual Salamander Lineage and Two Ancestral Sexual Species’ in Evolution (2018)
Laskowski, Doran, Bierbach, Krause and Wolf, ‘Naturally Clonal Vertebrates Are an Untapped Resource’
V. Volobouev and G. Pasteur, ‘Chromosomal Evidence for a Hybrid Origin of Diploid Parthenogenetic Females from the Unisexual-bisexual Lepidodactylus lugubris Complex’ in Cytogenetics and Cell Genetics, 63 (1993), pp. 194–9
Laskowski, Doran, Bierbach, Krause and Wolf, ‘Naturally Clonal Vertebrates are an Untapped Resource’
Yehudah L. Werner, ‘Apparent Homosexual Behaviour in an All-female Population of a Lizard, Lepidodactylus lugubris and its Probable Interpretation’ in Zeitschrift für Tierpsychologie, 54 (1980), pp. 144–50
David Crews, ‘ “Sexual” Behavior in Parthenogenetic Lizards (Cnemidophorus) ’in PNAS, 77: 1 (1980), pp. 499–502
L. A. O’Connell, B. J. Matthews, D. Crews, ‘Neuronal Nitric Oxide Synthase as a Substrate for the Evolution of Pseudosexual Behaviour in a Parthenogenetic Whiptail Lizard’ in Journal of Neuroendocrinology, 23 (2011), pp. 244–53
David Crews, ‘The Problem with Gender’ in Psychobiology, 16: 4 (1988),pp.321–34
Beth E. Leuck, ‘Comparative Burrow Use and Activity Patterns of Parthenogenetic and Bisexual Whiptail Lizards (Cnemidophorus: Teiidae)’ in Copeia, 2 (1982), pp. 416–24
Sarah P. Otto and Scott L. Nuismer, ‘Species Interactions and the Evolution of Sex’ in Science, 304: 5673 (2004), pp. 1018–20
T. Yashiro, N. Lo, K. Kobayashi, T. Nozaki, T. Fuchikawa, N. Mizumoto, Y.Namba and K. Matsuura, ‘Loss of Males from Mixed-sex Societies in Termites’ in BMC Biology, 16 (2018)
Lisa Margonelli, Underbug: An Obsessive Tale of Termites and Technology(Scientific American, 2018)
Toshihisa Yashiro and Kenji Matsuura, ‘Termite Queens Close the Sperm Gates of Eggs to Switch from Sexual to Asexual Reproduction’ in PNAS, 111: 48 (2014), pp.17212–17
Yashiro, Lo, Kobayashi, Nozaki, Fuchikawa, Mizumoto, Namba and Matsuura,‘Loss of Males from Mixed-sex Societies’
Roger Highfield, ‘Shark’s Virgin Birth Stuns Scientists’, Telegraph, 23 May 2007
Warren Booth and Gordon W. Schuett, ‘The Emerging Phylogenetic Pattern of Parthenogenesis in Snakes’ in Biological Journal of the Linnean Society (2015), pp. 1–15
Andrew T. Fields, Kevin A. Feldheim, Gregg R. Poulakis and Demian D.Chapman, ‘Facultative Parthenogenesis in a Critically Endangered Wild Vertebrate’ in Current Biology (Cell Press), 25: 11(2015), pp. 446–7
孤雌生殖也有许多不同方式。——译者注
Kat McGowan, ‘When Pseudosex is Better Than the Real Thing’, Nautilus, Nov.2016, https://nautil.us/issue/42/fakes/ when-pseudosex-is-better-than-the-real-thing
Fields, Feldheim, Poulakis and Chapman, ‘Facultative Parthenogenesis in a Critically Endangered Wild Vertebrate’
产雄孤雌生殖是一种特殊的孤雌生殖方式，可以产生雄性个体，但这些雄性无法进行自我繁殖，只有雌性才具有这种特殊能力。大多数蜜蜂、蚂蚁和黄蜂都以这种方式繁殖：雌性由受精卵产生，雄性由未受精卵产生。科莫多巨蜥是已知的少数能够通过这种无性生殖方式产生雄性后代的脊椎动物之一，这源自其独特的ZW性别决定系统——雄性的性染色体是ZZ，雌性是ZW。科莫多巨蜥的孤雌生殖只会产生一种可存活的性别，那就是只有一条性染色体Z的雄性。我在伦敦动物学会的伦敦动物园遇到了这样一只名叫甘纳斯的爬行动物。他的母亲弗洛拉是研究人员从野外捕获的，不仅能够无性生殖，还生了一只雄性后代，这让动物园的工作人员感到惊讶。
20世纪30年代，避孕药的共同发明人格雷戈里·古德温·平卡斯声称，他在实验室中通过用盐水、激素和热处理卵子，创造了一只“没有父亲”的兔子。由此产生的克隆兔子成为封面大明星。但是，其他人使用相同方式并未能够诱导出所谓的兔子孤雌生殖，人们对他实验的有效性产生了怀疑。（N. I. Werthessen, ‘Pincogenesis – Parthenogenesis in Rabbits by Gregory Pincus’in Perspectives in Biology and Medicine, 18: 1 (1974), pp. 86–93）几十年后的2004年，一个日本实验室通过人工诱导孤雌生殖培育出了一只雌性小鼠，她成功活了下来，并继续繁衍后代。
