Evidence for Costs of Mating and Self-Fertilization in a Simultaneous Hermaphrodite With Hypodermic Insemination, the Opisthobranch Alderia willowi
Evidence for Costs of Mating and Self-Fertilization in a Simultaneous Hermaphrodite With Hypodermic Insemination, the Opisthobranch Alderia willowi
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皮下授精同时雌雄同体（后鳃金龟 Alderia willowi）交配和自体受精成本的证据
DOI：
10.1086/bblv216n2p188
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Krug
中科院分区：
文献类型：
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作者：
N. Smolensky;M. R. Romero;P. Krug
同时雌雄同体提供了一个机会，研究两性之间的对抗共同进化时，个人功能在两个角色。通过皮下授精的创伤性交配在两性类群中反复进化，但缺乏这种雄性优势性状的适应性成本的证据。当在隔离饲养时，海蛞蝓Alderia willowi（后鳃亚纲：囊舌纲）的标本最初会产下一窝未受精的卵，但4天后开始自交;这只是第三次在后鳃中自交的报道。皮下授精可能会允许自交Alderia，如果穿透体壁绕过内部机制，促进异交。与孤立的蛞蝓相比，自交标本和成对饲养的蛞蝓的繁殖力降低，这表明皮下授精会增加交配的成本。产蛋量增加，现场捕获的蛞蝓交配后分开的蛞蝓举行的对，进一步表明，可访问性的配偶施加健身成本的女性功能。这种拮抗作用可以赋予蛞蝓在雄性角色中交配的竞争优势，但在能够长期储存精子的雌雄同体中减少雌性角色的繁殖。Alderia willowi也是一种罕见的Poecilogony，成虫产生营养型或营养型幼虫。我们的饲养研究表明，大多数蛞蝓在某个时候在表达的发育模式之间切换;这种个体内的生殖灵活性是前所未有的，即使在poecilogonous物种中也是如此。
Simultaneous hermaphrodites offer the chance to study antagonistic coevolution between the sexes when individuals function in both roles. Traumatic mating by hypodermic insemination has repeatedly evolved in hermaphroditic taxa, but evidence for the fitness costs of such male-advantage traits is lacking. When reared in isolation, specimens of the sea slug Alderia willowi (Opisthobranchia: Sacoglossa) initially laid clutches of unfertilized eggs but 4 days later began self-fertilizing; this is only the third report of selfing in an opisthobranch. Hypodermic insemination may allow selfing in Alderia if penetration of the body wall bypasses internal mechanisms that promote outcrossing. Selfing specimens and slugs reared in pairs had reduced fecundity compared to isolated slugs laying unfertilized clutches, suggesting that hypodermic insemination imposes a cost of mating. Egg production increased for field-caught slugs separated after mating compared to slugs held in pairs, a further indication that accessibility to mates imposes a fitness cost to the female function. Such antagonism can confer a competitive advantage to slugs mating in the male role but diminish reproduction in the female role among hermaphrodites capable of long-term sperm storage. Alderia willowi is also a rare case of poecilogony, with adults producing either planktotrophic or lecithotrophic larvae. Our rearing studies revealed that most slugs switched between expressed development modes at some point; such reproductive flexibility within individuals is unprecedented, even among poecilogonous species.