Does multiple paternity explain phenotypic variation among offspring in wild boar?

During pregnancy, littermates compete to extract maternal resources from the placenta. Unequal extraction of resources leads to developmental differences among offspring and thus within-litter variation in offspring mass. Because competition among littermates can be stronger among half-sibs, multiple paternity may represent an adaptive strategy allowing females to increase within-litter phenotypic variation among offspring when facing variable environments. Wild boar (Sus scrofa) females produce large litters with diversified offspring in terms of body mass. Additionally, multiple paternity within a litter has been observed in this promiscuous species. One can hypothesize that multiple paternity represents the mechanism by which females increase within-litter phenotypic variation. Combining long-term monitoring data with paternity analyses in a wild boar population, we tested whether the increase in the number of fathers within a litter explained the increase in within-litter variation ...妊娠期间，同窝幼崽会竞争从胎盘获取母体资源。资源获取的不均等会导致幼崽间发育差异，进而造成同窝幼崽体重的个体差异。由于同窝幼崽间的竞争在半同胞个体中更为激烈，多父本（multiple paternity）或许是一种适应性策略，可使雌性个体在环境多变时提升幼崽的同窝表型变异程度。野猪（Sus scrofa）的雌性个体可产下大窝幼崽，且幼崽间体重存在显著分化；此外，在这种混杂交配的物种中，已有研究发现同窝幼崽存在多父本现象。据此可提出假说：多父本是雌性提升幼崽同窝表型变异的机制。本研究结合野猪种群的长期监测数据与父本分析，验证了同窝幼崽的父本数量增加是否能够解释同窝幼崽的表型变异提升……