Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road, Mississauga, ON, Canada L5L 1C6.
J Insect Physiol. 2013 Mar;59(3):306-10. doi: 10.1016/j.jinsphys.2012.08.016. Epub 2012 Nov 20.
It is common for females from many species to mate with multiple males within one reproductive cycle. As a result, sperm from different males come into contact in the female reproductive organs, where they compete for ova fertilization. This sperm competition appears to drive the ejaculation of a greater number of sperm than required to fertilize the ova. Both models and experimental observations indicate that males adjust the number of sperm in their ejaculate to the presence of rival males. Here, we show that Drosophila melanogaster males increase sperm allocation immediately after perceiving the presence of other males, but not females. Consistent with previous reports, we show that males use both auditory and olfactory modalities to determine the identity of potential rivals in their environment and we further show that these modalities are required for males to modulate sperm allocation. Our results support the sperm competition risk assessment theory, which predicts that males increase sperm allocation while perceiving the immediate risk of sperm competition, and reconcile previous observations in D. melanogaster that were at odds with this model.
许多物种的雌性在一个繁殖周期内与多个雄性交配是很常见的。因此，不同雄性的精子在雌性生殖器官内相遇，它们在那里竞争卵子的受精。这种精子竞争似乎促使雄性射出比受精所需数量更多的精子。模型和实验观察都表明，雄性会根据竞争对手雄性的存在来调整精液中的精子数量。在这里，我们表明，果蝇雄性在感知到其他雄性存在后会立即增加精子分配，但不会对雌性产生这种反应。与之前的报告一致，我们表明，雄性使用听觉和嗅觉两种模式来确定环境中潜在竞争对手的身份，我们进一步表明，这些模式是雄性调节精子分配所必需的。我们的研究结果支持精子竞争风险评估理论，该理论预测雄性在感知到精子竞争的直接风险时会增加精子分配，同时也解释了之前在 D. melanogaster 中与该模型不一致的观察结果。
