Sexual Selection and Viability in the Wild: the Evolution of Sex Differences

性选择和野外生存能力：性别差异的进化

• 批准号: RGPIN-2015-06740
• 负责人: Gwynne, Darryl
• 金额: $ 2.33万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=684432
• 关键词: Sexual; Selection; Viability; Wild; Evolution

Sexual selection explains the evolution of sex differences such as ornamentation and sexually-competitive behaviour. Although important research investigating this process uses lab model organisms, there are some aspects that can only be fully addressed in the wild. These include tests of a central issue about sexual selection: is it opposed (Darwin 1871) or in the same direction as viability selection? Our research addresses this, and the factors thought to control sex differences, by using novel insect mating systems with sexual selection on females in competition for valuable donations from males. In two systems females possess "male-like" ornaments.******We propose to use formal selection analyses and field experiments to measure viability and sexual selection on female traits in the wild using: (a) female Rhamphomyia dance flies that risk predation by spiders when displaying ornaments that attract males bearing prey gifts (the only source of protein for females); (b) Female Oecanthus tree crickets at greater risk than males from wasp parasitoids when moving, as when approaching their mates to obtain valuable gift secretions. Additionally, behavioural observations and experiments will test the prediction that male choice in Oecanthus causes sexual selection on females. System (c) involves many species of Hemiandrus weta (related to crickets) where males deliver to ornamented females `gift' meals along with a sperm package. ******Sexual and viability selection will be estimated in the same time frame by comparing both mating success and mortality from predation. For the flies and crickets, we will analyze sperm stores of fresh-prey females compared to survivors using newly developed microsatellite DNA variation to determine lifetime female mating frequency and thus sexual selection on traits. A Darwinian prediction is that highly-ornamented, frequently mating females run a greater risk of predation. For viability selection we compare traits of our prey females to those of survivors. We will also estimate lifespans of females by marking and recapturing. As selection analyses on unmanipulated natural populations are correlative, sampling of prey and survivors will be followed by field experiments using established methods of releasing dance fly females with differing levels of trait expression near webs mounted in frames. Study system (c) involves a speciose weta genus, Hemiandrus. In addition to selection analyses, a molecular phylogeny developed by collaborators will allow a comparative approach to sexual selection and the evolution of female ornaments. Some species exhibit maternal care and some, abdominal ornamentation. Frequent female mating (gift acquisition) in species with maternal care is hypothesized to promote survival through a long period of starvation while caring. This predicts a phylogenetic association of ornaments with maternal care.**

性选择解释了性别差异的进化，如性取向和性竞争行为。虽然调查这一过程的重要研究使用实验室模型生物，但有些方面只能在野外完全解决。这些测试包括对性选择的一个核心问题的测试：性选择是与生存力选择相反的（达尔文，1871）还是与生存力选择相同的方向？我们的研究解决了这一问题，并认为控制性别差异的因素，通过使用新的昆虫交配系统，对女性进行性选择，以竞争男性的宝贵捐赠。在两个系统中，女性拥有“男性般”的装饰品。我们建议使用正式的选择分析和田间实验，以衡量生存能力和性选择的女性特征在野外使用：（a）女性Rhamphomyia舞蹈苍蝇，风险捕食蜘蛛时，显示装饰品，吸引男性携带猎物礼物（女性唯一的蛋白质来源）;（B）雌性Oecanthus树蟋蟀在移动时，如接近配偶以获得有价值的礼物分泌物时，比雄性更容易受到黄蜂寄生蜂的威胁。此外，行为的观察和实验将测试的预测，男性的选择Oecanthus导致女性的性选择。系统（c）涉及许多种类的半andrus weta（与蟋蟀有关），其中雄性将“礼物”餐沿着精子包一起提供给被引诱的雌性。** 将通过比较交配成功率和捕食死亡率在同一时间范围内估计性选择和生存力选择。对于苍蝇和蟋蟀，我们将使用新开发的微卫星DNA变异来分析新鲜猎物雌性与幸存者相比的精子储存，以确定一生的雌性交配频率，从而确定性状的性选择。达尔文的一个预测是，高度敏感、频繁交配的雌性动物被捕食的风险更大。对于生存能力的选择，我们比较我们的猎物女性的幸存者的特征。我们还将通过标记和重新捕获来估计女性的寿命。作为选择分析未操纵的自然种群是相关的，猎物和幸存者的采样将遵循现场实验，使用既定的方法释放舞蝇女性与不同水平的特征表达附近的网站安装在框架中。研究系统（c）涉及一种特殊的沙獭属，半雄沙獭。除了选择分析之外，合作者开发的分子遗传学将允许对性选择和女性装饰物的进化进行比较。有些物种表现出母性关怀，有些则表现出腹式关怀。频繁的女性交配（礼物收购）的物种与母亲照顾的假设，以促进生存，通过长期的饥饿，而照顾。这预示着装饰品与母亲护理的系统发育关联。