The fate of received sperm in the reproductive tract of a hermaphroditic snail and its implications for fertilisation
The fate of received sperm in the reproductive tract of a hermaphroditic snail and its implications for fertilisation
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雌雄同体蜗牛生殖道中收到的精子的命运及其对受精的影响
DOI：
10.1007/s10682-008-9253-5
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发表时间：
2009
影响因子：
1.9
通讯作者：
A. ter Maat
中科院分区：
文献类型：
--
作者：
J. Koene;Kora Montagne;D. Roelofs;A. ter Maat
多次交配、精子储存和体内受精增强了精子的竞争。池塘大蜗牛可以使用储存的精子超过三个月，并且经常与不同的伴侣交配。这种雌雄同体的 Lymnaea stagnalis 也可以自体受精，并且经常产生含有自交和异交卵的卵块。因此，精子接受者可以对亲子关系施加相当大的控制。使用微卫星标记，我们表明当存在异种植物时，所有基因分型的卵都会交叉受精。我们还发现精子有机会竞争，因为双重交配平均会导致每个精子捐献者的父权平等。这表明收到的精子在储存中是随机混合的。为了进一步了解精子储存、消化和利用过程的潜在机制，我们研究了交配后不同时间捐赠精子的命运。我们发现，在移植后 3 小时内，大多数精子已被输送到精子消化器官中。组织学切片中精子的荧光标记进一步揭示，同种异精不储存在受精袋中，而是储存在雌雄同体管、精囊或卵睾的上游。除了有助于理解精子竞争和/或神秘精子选择的机制之外，这项研究还表明，在雌雄同体动物中，混合交配不能被视为一个单独的问题。
Multiple mating, sperm storage and internal fertilisation enhance sperm competition. The great pond snail can use stored sperm for over three months, and frequently mates with different partners. This hermaphrodite,Lymnaea stagnalis, can also self-fertilise and often produces egg masses containing both selfed and outcrossed eggs. Hence, a sperm recipient may exert considerable control over paternity. Using microsatellite markers, we show that when allosperm are present, all genotyped eggs are cross-fertilised. We also find that sperm have the opportunity to compete, because double matings lead on average to equal paternity for each sperm donor. This indicates that received sperm are randomly mixed in storage. To gain further insight into the mechanisms underlying the process of sperm storage, digestion and utilisation, we investigated the fate of donated sperm at different times after copulation. We find that within 3 h after transfer most sperm have been transported into the sperm-digesting organ. Fluorescent labelling of sperm in histological sections further reveals that allosperm are not stored in the fertilisation pouch, but upstream in either the hermaphroditic duct, seminal vesicles, or ovotestis. Besides contributing to the understanding of the mechanisms underlying sperm competition and/or cryptic sperm choice, this study shows that mixed mating cannot be treated as a separate issue in hermaphroditic animals.