Sexual reproduction and diapause of Hexarthra sp. (Rotifera) in short‐lived ponds in the Chihuahuan Desert
Sexual reproduction and diapause of Hexarthra sp. (Rotifera) in short‐lived ponds in the Chihuahuan Desert
复制标题
奇瓦瓦沙漠短寿命池塘中轮虫的有性繁殖和滞育
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
E. Walsh
中科院分区：
文献类型：
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作者：
T. Schröder;S. Howard;M. Arroyo;E. Walsh
摘要1.在单性轮虫的生活史中，通常认为滞育的卵总是孵化成雌雄配子，从而产生雌性单性生殖后代。滞育卵只有在环境提示诱导有性繁殖后才会由后代产生。2.我们发现，栖息在奇瓦瓦沙漠临时小池塘中的一种未描述的六角类物种的种群偏离了这一生活史模式。这些池塘可能在几天内就会干涸，高达85%的雌性大小便。池塘满水后，雌虫分别观察1天和2天后产生雄性后代和滞育卵。3.在实验室条件下，从重新水化的沉积物中孵化的雌性幼虫中有7%-46%是有性行为的。这些雌性的雄性后代可以与其他混血茎雌性受精，从而形成滞育卵。在室内实验中，雌虫在20�C和30�C条件下分别在1.9d和1.2d内产下完全发育的滞育卵。此外，在12~30�C温度范围内胚胎发育时间(1.1d~0.3d)和幼虫发育期(2.1d~0.5d)均短于其他轮虫。在短期栖息地，种群快速发展和产生新的滞育卵的潜力可能对种群的长期生存至关重要。
SUMMARY 1. In the life cycle of monogonont rotifers it is generally assumed that diapausing eggs invariably hatch into amictic stem females which produce female offspring parthenogenetically. Diapausing eggs are only produced by later generations after sexual reproduction has been induced by environmental cues. 2. We show that populations of an undescribed Hexarthra species inhabiting small temporary ponds in the Chihuahuan Desert deviate from this life cycle pattern. These ponds may dry within days and up to 85% of females were mictic. Females producing male offspring and diapausing eggs were observed 1 or 2 days, respectively, after ponds had filled with water. 3. Under laboratory conditions, 7–46% of females hatching from re-hydrated sediments were sexual. Male offspring of these females can fertilise other mictic stem females leading to diapausing egg formation. In laboratory experiments, females produced fully developed diapausing eggs within 1.9 days at 20 � C and 1.2 days at 30 � C. 4. In addition, embryonic development time (1.1–0.3 days at temperatures between 12 and 30 � C) and juvenile period (2.1–0.5 days for the same temperature range) are shorter than those of other rotifer species. In short-lived habitats, the potential for rapid population development and production of new diapausing eggs may be crucial in the long-term survival of populations.