Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.
School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.
Ecol Lett. 2016 Jun;19(6):687-96. doi: 10.1111/ele.12607. Epub 2016 May 5.
Species' life history traits, including maturation age, number of reproductive bouts, offspring size and number, reflect adaptations to diverse biotic and abiotic selection pressures. A striking example of divergent life histories is the evolution of either iteroparity (breeding multiple times) or semelparity (breed once and die). We analysed published data on salmonid fishes and found that semelparous species produce larger eggs, that egg size and number increase with salmonid body size among populations and species and that migratory behaviour and parity interact. We developed three hypotheses that might explain the patterns in our data and evaluated them in a stage-structured modelling framework accounting for different growth and survival scenarios. Our models predict the observation of small eggs in iteroparous species when egg size is costly to maternal survival or egg number is constrained. By exploring trait co-variation in salmonids, we generate new hypotheses for the evolution of trade-offs among life history traits.
物种的生活史特征，包括成熟年龄、繁殖次数、后代大小和数量，反映了对不同生物和非生物选择压力的适应。一个明显的例子是多次生殖（多次繁殖）或单次生殖（繁殖一次后死亡）的生活史的分歧。我们分析了鲑鱼的数据，并发现单次生殖的物种产的卵更大，在种群和物种中，卵的大小和数量随鲑鱼体型的增加而增加，并且迁移行为和生殖次数相互作用。我们提出了三个可能解释数据模式的假设，并在一个考虑不同生长和存活情况的结构化模型框架中对其进行了评估。我们的模型预测，当卵子大小对母体生存有代价或卵子数量受到限制时，多次生殖的物种会产生小卵子。通过探索鲑鱼的特征协同变化，我们为生活史特征之间权衡的进化产生了新的假设。
