Seasonal and inter-species comparison of asymmetry in the genital system of some species of the oceanic copepod genus Metridia (Copepoda, Calanoida)
Seasonal and inter-species comparison of asymmetry in the genital system of some species of the oceanic copepod genus Metridia (Copepoda, Calanoida)
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海洋桡足类Metridia（Copepoda、Calanoida）某些物种生殖系统不对称性的季节和种间比较
DOI：
10.1163/15685403-00003485
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发表时间：
2015
期刊：
影响因子：
0.6
通讯作者：
T. Nobetsu and I Imai
中科院分区：
文献类型：
--
作者：
Arima;D.;K. Matsuno;A. Yamaguchi;T. Nobetsu and I Imai
本文报道了鄂霍氏平鳃水蚤Metridia okhotensis和M.在鄂霍次克海进行了调查。这两个参数的物种间的比较也进行了七Metridiaspecies收集来自世界各地的海洋。ForM.鄂霍次克海鄂霍次克海第二外足节长内突的左侧授精率（年均95.7%）和左侧不对称率（年均99.7%）均为雌性。然而，sympatricM.太平洋的雌性受精率和雄性形态型的不对称率各不相同，全年的比例为左：右= 1：2。在这项研究中，来自全球海洋的七个Metridiasspecies的雌性受精和雄性形态型的不对称比例相互相关。单侧授精（即，仅左侧授精或仅右侧授精）是全球海洋中各种Metridiasspecies的共同模式，但它们的比例因物种而异。以前，各种Metridiaspp的卵孵化率低（29-68%）。在实验室实验中，但这些低利率的原因尚不清楚。因为Metridiaspp.与输卵管同侧相连，无论是左还是右，这表明单侧授精的雌性产生的一半卵子仍然未受精。本文报道了长角尺蛾生殖器的形态结构和卵孵化率的文献资料。这表明，几乎一半的卵子产生的女性是没有活力的，因此，浪费。
The seasonal and inter-annual changes in the asymmetry of female insemination and the male leg 5 of the planktonic calanoid copepodsMetridia okhotensisandM. pacificawere investigated in the Okhotsk Sea. An inter-species comparison of both parameters was also carried out on sevenMetridiaspecies collected from oceans throughout the world. ForM. okhotensisfrom the Okhotsk Sea, most of the females showed left-side insemination (annual average: 95.7%) and most of the males showed left-side asymmetry (99.7%) of the long inner process of the second exopodal segment in the fifth leg throughout the year. However, sympatricM. pacificashowed different ratios of asymmetry for female insemination and male morphotypes with a left : right = 1 : 2 ratio throughout the year. For the sevenMetridiaspecies from the global oceans treated in this study, ratios of asymmetry for female insemination and male morphotypes were correlated with each other. One-sided insemination (i.e., only left or only right insemination) was a common pattern for variousMetridiaspecies from global oceans, but their ratios varied by species. Previously, low hatching rates (29-68%) of eggs were reported for variousMetridiaspp. in laboratory experiments, but the reasons for these low rates were unclear. Because each spermatheca ofMetridiaspp. is connected to the oviduct on the same side, either left or right, this suggests that half of the eggs produced by unilaterally inseminated females remain unfertilized. The morphology of the genital structures and literature data of the egg hatching rates ofMetridiaspp. indicate that almost half of the eggs produced by females are not viable and are, thus, wasted.