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首页> 外文学位 >Protogynous hermaphroditism in a temperate reef fish, the blackeye goby, Coryphopterus nicholsii (Pisces: Gobiidae).
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Protogynous hermaphroditism in a temperate reef fish, the blackeye goby, Coryphopterus nicholsii (Pisces: Gobiidae).

机译：在温带珊瑚鱼中的雌雄同体，黑眼虾虎鱼Coryphopterus nicholsii（双鱼座：戈壁科）。

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摘要

In this thesis, I examine the occurrence of protogynous hermaphroditism in the blackeye goby, Coryphopterus nicholsii (Pisces, Gobiidae) at Bamfield, Vancouver Island, Canada. The female biased sex ratios, size distributions of female and male C. nicholsii, and histological data all confirm that the species is protogynous. Histological data strongly suggest two patterns of sexual ontogeny, with males resulting from either pre- or post-maturational sex change. Sex change is not common during, and immediately after the breeding season.;The social organization of C. nicholsii is based upon the year-round defense of a territory, primarily by large individuals of both sexes. A territory always includes one or more shelter rocks. These are used as refuges by both sexes, and as nest sites by males during the breeding season. The defence of a shelter rock is important in reproduction, in the reduction of predation, and the avoidance of adverse environmental conditions. Suitable refuge and nest site rocks are a limited resource and intraspecific competition determines which individuals gain access to them. Since the outcome of competition for suitable shelter rocks is strongly size-specific, large males monopolize spawnings.;Large males receive a disproportionate share of the matings: males smaller than 7.0 cm were never seen nesting in the field. Yet, approximately 30% of males are smaller than 7.0 cm, indicating that many females change sex at smaller sizes. This early sex change confers a growth advantage: small, non-nesting males grow faster than similarly-sized mature females. As a result, small males may obtain nesting male status more rapidly than females that change sex later in life. The presence of early sex changers may also be related to an alternative mating tactic, sneak spawning.;Sex change is correlated with a reduction in whole-body concentration of 17;These results are discussed with regards to the geographical disparity of protogynous hermaphroditism in teleosts. Protogyny occurs much more frequently on tropical coral reefs than on temperate rocky reefs. I propose that a difference in the occurrence of certain mating systems in tropical and temperate waters partly explains this disparity.
机译：在这篇论文中，我研究了加拿大温哥华岛班菲尔德黑眼虾虎鱼Coryphopterus nicholsii（双鱼座，戈壁科）中雌雄同体性生殖的发生。雌性偏性比例，雌性和雄性念珠菌的大小分布以及组织学数据均证实该物种是原生的。组织学数据强烈暗示了两种形式的性个体发育，其中男性来自成熟前或成熟后的性别变化。在繁殖季节以及紧随其后的季节，性别变化并不常见。C. nicholsii的社会组织是基于对一个领土的全年防御，主要是由两性的大型个体进行的。一个领土始终包含一个或多个掩体。它们在雌雄同体都被用作避难所，在繁殖季节被雄性用作筑巢地。围岩的防御对于繁殖，减少捕食和避免不利的环境条件至关重要。合适的避难所和巢穴岩石资源有限，种内竞争决定了哪些人可以使用它们。由于争夺合适的围岩的结果是严格针对大小的，因此大型雄性会垄断卵子。大雄性的交配比例不成比例：在田野中从未见过小于7.0 cm的雄性筑巢。但是，大约30％的男性小于7.0厘米，表明许多女性以较小的尺寸改变性别。这种早期的性别变化赋予了生长优势：小的，非巢状的雄性比同等大小的成年雌性增长更快。结果，小的雄性可能比在晚年改变性别的雌性更快地获得雄性。早期的性改变者的存在也可能与另一种交配策略即潜行产卵有关;性改变与全身浓度降低17相关;讨论了硬骨的雌雄同性雌雄同体的地理差异。与热带温带礁石相比，Protogyny发生在热带珊瑚礁上的频率要高得多。我建议热带和温带水域某些交配系统的发生差异部分地解释了这种差异。

著录项

  • 作者

    Kroon, Frederieke Janet.;

  • 作者单位

    The University of British Columbia (Canada).;

  • 授予单位 The University of British Columbia (Canada).;
  • 学科 Biology Zoology.
  • 学位 Ph.D.
  • 年度 1997
  • 页码 148 p.
  • 总页数 148
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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