School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
Science. 2011 Sep 23;333(6050):1739-42. doi: 10.1126/science.1207314.
The widespread phenomenon of polyandry (mating by females with multiple males) is an evolutionary puzzle, because females can sustain costs from promiscuity, whereas full fertility can be provided by a single male. Using the red flour beetle, Tribolium castaneum, we identify major fitness benefits of polyandry to females under inbreeding, when the risks of fertilization by incompatible male haplotypes are especially high. Fifteen generations after inbred populations had passed through genetic bottlenecks, we recorded increased levels of female promiscuity compared with noninbred controls, most likely due to selection from prospective fitness gains through polyandry. These data illustrate how this common mating pattern can evolve if population genetic bottlenecks increase the risks of fitness depression due to fertilization by sperm carrying genetically incompatible haplotypes.
多配偶制（雌性与多个雄性交配）的广泛现象是一个进化谜题，因为雌性可能会因滥交而付出代价，而单一雄性就能提供完全的生育能力。利用红粉甲虫，Tribolium castaneum，我们发现了多配偶制对雌性在近亲繁殖下的主要适应优势，因为此时与不兼容的雄性单倍型受精的风险特别高。在经过遗传瓶颈的近交种群经过十五代后，与非近交对照相比，我们记录到了雌性滥交水平的增加，这很可能是由于通过多配偶制获得预期的适应增益而产生的选择。这些数据说明了如果种群遗传瓶颈增加了由于携带遗传上不兼容单倍型的精子受精而导致适应力下降的风险，这种常见的交配模式是如何进化的。
