Title page for etd-0924113-130058


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URN etd-0924113-130058
Author Guan-lin Yu
Author's Email Address No Public.
Statistics This thesis had been viewed 5568 times. Download 215 times.
Department Department of Oceanography
Year 2013
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Study of male-biased sex ratios in the sea urchin Tripneustes gratilla in Taiwan
Date of Defense 2013-10-14
Page Count 52
Keyword
  • predator sex selection
  • Sea urchin
  • sex ratio
  • male biased
  • Abstract A male-biased sex ratio was observed in the sea urchins (Tripneustes gratilla, Linnaeus) around Taiwan between 2010 and 2013. In Kenting, south Taiwan, more biased sex ratios were found among larger individuals. Here, we tested the hypotheses of predators, genetic,and sampling biase. We discovered that sex ratio would vary with season, this falsifies the hypothesis of genetics. The external shapes, as compared by height-diameter ratios, and the masking behavior, carrying objects on their aboral surface, were not different between males and females.
    No biase in sex ratio was found in an artificial culture facility whereas field collection indicated a male-biased phenomenon in Penghu in Jul 21 2013. All these evidence are compatible only with the predator hypothesis in which selective predators preferentially feed on females. Based on change of sex ratios, we estimate that the lowest mortality rate was 34% per 1.7 months at Penghu, and was 32% per 1.3 months at Houbihu during the spawning season.
    Advisory Committee
  • Shyh-Min Chao - chair
  • Jin-Hua Cheng - co-chair
  • Keryea Soong - advisor
  • Files
  • etd-0924113-130058.pdf
  • Indicate in-campus at 1 year and off-campus access at 5 year.
    Date of Submission 2013-10-25

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