Production of male neonates in Daphnia magna (Cladocera, Crustacea) exposed to juvenile hormones and their analogs
Production of male neonates in Daphnia magna (Cladocera, Crustacea) exposed to juvenile hormones and their analogs
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DOI：
10.1016/j.chemosphere.2005.02.075
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发表时间：
2005-12-01
期刊：
影响因子：
8.8
通讯作者：
Iguchi, T
中科院分区：
文献类型：
--
作者：
Oda, S;Tatarazako, N;Iguchi, T
我们暴露的水蚤大型（枝角类，甲壳纲）无论是保幼激素I（JH I），保幼激素II（JH II），或少年的拟杀昆虫kinoprene，烯虫乙酯，epofenonane，或苯氧威。通过21天的繁殖试验，研究了对每头母鼠产仔数和子代性比的影响。所有6种化学物质均诱导D.大产生雄性新生儿;后代的雄性比例随着化学品浓度的增加而增加。雄性新生儿的半数有效浓度估计为400（JH I）、410（JH II）、190（Kinoprene）、2.9（Hydroprene）、64（epofenonane）和0.92（苯氧威）微克/升。在研究的浓度下，所有化学品的新生儿数量都有所减少。在雄性生殖的EC 50下，六种化学品中有五种将生殖率降低到50%以下;但epofenonane除外，它仅导致生殖率轻微降低。这些结果与先前研究的五种juvenoids所获得的结果相似，其中一种在这里再次研究。现在已知有10种化学物质--都是保幼激素或其类似物--可以诱导D。产下雄性新生儿。这表明保幼激素参与了D. magna，并且可能在大多数表现出周期性孤雌生殖的枝角类中。(c)2005爱思唯尔有限公司保留所有权利。
We exposed the water flea Daphnia magna (Cladocera, Crustacea) to either juvenile hormone I (JH I), juvenile hormone II (JH II), or the juvenile hormone-mimicking insecticides kinoprene, hydroprene, epofenonane, or fenoxycarb. By 21-day reproduction tests, we investigated the effects on the number of neonates born per female and the offspring sex ratio. All six chemicals induced D. magna to produce male neonates; the male sex ratio of the offspring increased as the chemical concentration increased. EC50 values for production of male neonates were estimated as 400 (JH I), 410 (JH II), 190 (kinoprene), 2.9 (hydroprene), 64 (epofenonane), and 0.92 (fenoxycarb) mu g/l. The number of neonates produced was reduced with all chemicals at the concentrations investigated. At the EC50 for male production, five of the six chemicals reduced the reproductive rate to less than 50%; the exception was epofenonane, which caused only a slight reduction in reproductive rate. These results were similar to those obtained for five juvenoids studied previously, one of which was studied here again. There are now 10 chemical substances-all juvenile hormones or their analogs-that are known to induce D. magna to produce male neonates. This suggests that juvenile hormone is involved in initiating male production followed by sexual reproduction in D. magna, and probably in most cladocerans that exhibit cyclic parthenogenesis. (c) 2005 Elsevier Ltd. All rights reserved.