Bisexual juvenile gonad and gonochorism in the fairy basslet, Gramma loreto
Bisexual juvenile gonad and gonochorism in the fairy basslet, Gramma loreto
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仙女鲈中的双性幼体性腺和雌雄异体现象，Gramma loreto
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
D. Shapiro
中科院分区：
文献类型：
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作者：
K. Asoh;D. Shapiro
根据性别分配理论，雌性先熟的物种应该形成一个社会系统，在这个系统中，相对较少的雄性与相对较多的雌性交配。因为仙女小鲈，Gramma洛雷托，以这种预测的方式交配，我们研究了它的性行为模式，寻找雌雄同体的证据，在167个标本中，从小的少年到成年人。所有的性腺最初都发育成了卵黄发生前的卵母细胞和精子导管的前体。在未来的男性，卵母细胞退化;导管增殖，闭塞，并成为精子运输;和生精组织出现。在未来的女性，卵巢腔形成，肿胀的精子管退化，卵母细胞继续生长。在一次诱导性逆转的实验中，雄性从自然种群转移到实验室的社会群体中被移除。雄性动物切除后5个月，没有雌性动物包含任何性别变化的组织学证据。因此，我们的数据强烈支持的假设，G。洛雷托是一个gonochore。该物种不符合预测之间的关系，雌性先熟和femalebased交配系统，也许是因为小，nonreproductive男性进化的替代手段，以避免低繁殖成功的增长速度比同样大小的女性。
According to sex allocation theory, protogynous species ought to form social systems in which a relatively small number of males mate with a relatively large number of females. Because the fairy basslet, Gramma loreto, mates in this predicted manner, we examined its mode of sexuality, looking for evidence of protogyny, in 167 specimens ranging in size from small juveniles through adults. All gonads initially developed previtellogenic oocytes and a precursor of the sperm ducts. In future males, the oocytes degenerated; the ducts proliferated, anastomosed, and became available for sperm transport; and spermatogenic tissue appeared. In future females, an ovarian lumen was formed, the precursive sperm ducts degenerated, and oocytes continued to grow. No histological features indicative of protogyny were found. In an experimental attempt to induce sex reversal, males were removed from social groups transferred from natural populations into the laboratory. Five months after male removal, no female contained any histological evidence of sex change. Thus, our data strongly support the hypothesis that G. loreto is a gonochore. The species does not conform to the predicted relationship between protogyny and a femalebiased mating system, perhaps because small, nonreproductive males evolved an alternative means of avoiding low reproductive success by growing faster than similarly sized females.