In this study, we addressed why Caenorhabditis elegans males are inefficient at fertilizing their hermaphrodites. During copulation, hermaphrodites generally move away from males before they become impregnated. C. elegans hermaphrodites reproduce by internal self-fertilization, so that copulation with males is not required for species propagation. The hermaphroditic mode of reproduction could potentially relax selection for genes that optimize male mating behavior. We examined males from hermaphroditic and gonochoristic (male–female copulation) Caenorhabditis species to determine if they use different sensory and motor mechanisms to control their mating behavior. Instead, we found through laser ablation analysis and behavioral observations that hermaphroditic C. briggsae and gonochoristic C. remanei and Caenorhabditis species 4, PB2801 males produce a factor that immobilizes females during copulation. This factor also stimulates the vulval slit to widen, so that the male copulatory spicules can easily insert. C. elegans and C. briggsae hermaphrodites are not affected by this factor. We suggest that sensory and motor execution of mating behavior have not significantly changed among males of different Caenorhabditis species; however, during the evolution of internal self-fertilization, hermaphrodites have lost the ability to respond to the male soporific-inducing factor.
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机译:在这项研究中,我们探讨了秀丽隐杆线虫男性为何不能有效地使雌雄同体受精的原因。在交配过程中,雌雄同体通常在雄性被浸渍之前就离开雄性。秀丽隐杆线虫雌雄同体通过内部自体受精繁殖,因此物种繁殖不需要与雄性交配。雌雄同体的繁殖方式可能会放松对优化雄性交配行为的基因的选择。我们检查了雌雄同体和生殖腺(雄性-雌性交配)的秀丽隐杆线虫物种,以确定他们是否使用不同的感觉和运动机制来控制其交配行为。取而代之的是,我们通过激光消融分析和行为观察发现,雌雄同体的C. briggsae和gonochoristic C. remanei和Caenorhabditis种类4,PB2801雄性产生了使雌性在交配过程中固定的因子。该因素还刺激外阴狭缝变宽,从而使雄性交配针容易插入。秀丽隐杆线虫和Briggsae雌雄同体不受此因素影响。我们认为,在不同种类的秀丽隐杆线虫男性中,感觉和运动交配行为的执行没有明显改变。但是,在内部自我受精的过程中,雌雄同体丧失了对雄性孢子诱导因子的反应能力。
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