Department of Biological and Environmental Sciences, PO Box 65, 00014 University of Helsinki, Finland.
J Evol Biol. 2011 Dec;24(12):2600-10. doi: 10.1111/j.1420-9101.2011.02383.x. Epub 2011 Sep 8.
In viviparous species, a conflict over maternal resource allocation may arise between mothers and embryos, between siblings, and between maternal and paternal genes within an embryo due to relatedness asymmetries. We performed two experiments to study the effects of polyandry and brood relatedness on offspring growth in a placental fish (Heterandria formosa). Polyandry was beneficial as it increased the probability of pregnancy, possibly to avoid genetic incompatibility. However, females mated to four males produced offspring that had a longer maturation time than those of monandrous females. When within-brood relatedness was manipulated, the size of the newborn offspring decreased with time in low-relatedness treatment, whereas in highly related broods, offspring size was constant. Low within-brood relatedness may lead to less cooperative offspring in terms of resource extraction from the mother, which may lead to impaired development during gestation. Offspring conflict may thus reduce the benefits of polyandry in viviparous species.
在胎生动物中，由于亲缘关系的不对称，母亲和胚胎之间、兄弟姐妹之间以及胚胎内的母系和父系基因之间可能会出现关于母体资源分配的冲突。我们进行了两项实验，以研究多配偶制和育雏亲缘关系对胎盘鱼类（Heterandria formosa）后代生长的影响。多配偶制是有益的，因为它增加了怀孕的可能性，可能是为了避免遗传不相容。然而，与单配偶制的雌性相比，与四只雄性交配的雌性所产的后代成熟时间更长。当操纵同窝内的亲缘关系时，在低亲缘关系处理中，新生后代的大小随时间减少，而在高度相关的育雏中，后代的大小保持不变。低同窝内的亲缘关系可能导致后代在从母亲那里提取资源方面的合作性降低，这可能导致妊娠期发育受损。因此，后代冲突可能会降低胎生动物中多配偶制的益处。
