Yasui Yukio, Garcia-Gonzalez Francisco
Laboratory of Entomology, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan.
Doñana Biological Station, Spanish Research Council CSIC, C/ Americo Vespucio s/n, 41092, Isla de la Cartuja, Seville, Spain.
Evolution. 2016 Feb;70(2):385-97. doi: 10.1111/evo.12847. Epub 2016 Jan 25.
Females that mate with multiple males (polyandry) may reduce the risk that their eggs are fertilized by a single unsuitable male. About 25 years ago it was hypothesized that bet-hedging could function as a mechanism favoring the evolution of polyandry, but this idea is controversial because theory indicates that bet-hedging via polyandry can compensate the costs of mating only in small populations. Nevertheless, populations are often spatially structured, and even in the absence of spatial structure, mate-choice opportunity can be limited to a few potential partners. We examined the effectiveness of bet-hedging in such situations with simulations carried out under two scenarios: (1) intrinsic male quality, with offspring survival determined by male phenotype (male's ability to generate viable offspring), and (2) genetic incompatibility (offspring fitness determined nonadditively by parental genotypes). We find higher fixation probabilities for a polyandrous strategy compared to a monandrous strategy if complete reproductive failure due to male effects or parental incompatibility is pervasive in the population. Our results also indicate that bet-hedging polyandry can delay the extinction of small demes. Our results underscore the potential for bet-hedging to provide benefits to polyandrous females and have valuable implications for conservation biology.
与多个雄性交配（多配偶制）的雌性可能会降低其卵子被单个不合适的雄性受精的风险。大约25年前，有人提出风险分摊可能是有利于多配偶制进化的一种机制，但这一观点存在争议，因为理论表明，通过多配偶制进行风险分摊仅在小种群中才能补偿交配成本。然而，种群往往具有空间结构，而且即使没有空间结构，择偶机会也可能仅限于少数潜在配偶。我们通过在两种情况下进行模拟，研究了风险分摊在这种情况下的有效性：（1）雄性内在质量，后代的存活由雄性表型（雄性产生有活力后代的能力）决定；（2）基因不相容性（后代适合度由亲本基因型非加性决定）。我们发现，如果由于雄性效应或亲本不相容导致的完全繁殖失败在种群中普遍存在，那么与单配偶制策略相比，多配偶制策略具有更高的固定概率。我们的结果还表明，风险分摊的多配偶制可以延缓小种群的灭绝。我们的结果强调了风险分摊为多配偶制雌性带来好处的潜力，并对保护生物学具有重要意义。
