Data from: Seasonal genetic variation associated with population dynamics of a poecilogonous polychaete worm

Poecilogonous species show variation in developmental mode, with larvae that differ both morphologically and ecologically. The spionid polychaete Pygospio elegans shows variation in developmental mode not only between populations, but also seasonally within populations. We investigated the consequences of this developmental polymorphism on the spatial and seasonal genetic structure of P. elegans at four sites in the Danish Isefjord-Roskilde-Fjord estuary at six time points, from March 2014 until February 2015. We found genetic differentiation between our sampling sites as well as seasonal differentiation at two of the sites. The seasonal genetic shift correlated with the appearance of new size cohorts in the populations. Additionally, we found that the genetic composition of reproductive individuals did not always reflect the genetic composition of the entire sample, indicating that variance in reproductive success among individuals is a likely explanation for the patterns of chaotic genetic patchiness observed during this and previous studies. The heterogeneous, unpredictable character of the estuary might maintain poecilogony in P. elegans as a bet-hedging strategy in the Isefjord-Roskilde-Fjord complex in comparison with other sites where P. elegans are expected to be fixed to a certain mode of development.

多型发育（Poecilogony）物种的发育模式存在变异，其幼虫在形态学与生态学特征上均存在差异。丝鳃虫科多毛类（spionid polychaete）优雅拟蛹沙蚕（Pygospio elegans）的发育模式不仅在不同种群间存在变异，在同一种群内部也存在季节尺度的变异。本研究以丹麦伊瑟峡湾-罗斯基勒峡湾河口区域的4个采样点为研究对象，于2014年3月至2015年2月间的6个时间节点开展采样调查，旨在探究该发育多态性对优雅拟蛹沙蚕空间与季节遗传结构所产生的影响。研究结果显示，各采样点间存在显著遗传分化，且其中2个采样点的种群呈现季节遗传分化特征。季节尺度的遗传偏移与种群中新体型群的出现呈显著相关。此外，本研究发现繁殖个体的遗传组成并不总能完整反映整个采样种群的遗传构成，这表明个体间繁殖成功率的差异，可作为解释本研究与既往研究中观测到的混沌遗传斑块（chaotic genetic patchiness）现象的潜在机制。相较于其他优雅拟蛹沙蚕发育模式固定的采样区域，伊瑟峡湾-罗斯基勒峡湾复合体河口的异质性与不可预测性特征，或可作为风险对冲（bet-hedging）策略，维持该物种的多型发育现象。