Multilevel selection on offspring size and the maintenance of variation

Data used to model multilevel selection on egg size under sperm saturating (H) and sperm limiting (L) conditions for the broadcast spawning polycheate, Galeolaria caespitosa. We used a split-clutch design to conduct in vitro fertilisations, whereby each female's clutch was split across 2 replicate fertilisations (Rep) per sperm treatment. We then measured the size-specific fertilisation success of all eggs within these clutch subsamples as a binary response variable (0 = unsuccessful eggs; 1 = successfully fertilised eggs). Note that values of clutch-mean in the dataset represents the mean-egg size of each female's clutch measured from photographs taken prior to fertilisation. Egg size represents the inital size of each indiviual egg prior to fertilisation, and has been back-calculated from measurements taken after fertilisation using equations that describe these relationships.本数据集用于建模精子饱和（H）与精子限制（L）条件下，散播产卵多毛类环节动物叠瓦管虫（Galeolaria caespitosa）的卵大小多级选择。本研究采用分卵群（split-clutch）实验设计开展体外受精实验：将每只雌性的卵群平均分配至每个精子处理组的2个重复受精（Rep）实验中。随后，我们将这些卵群子样本中所有卵的体型特异性受精成功率作为二元响应变量进行测量，赋值规则为：0代表未受精卵子，1代表成功受精卵子。请注意，本数据集中的`clutch-mean`字段代表每只雌性卵群的平均卵大小，该值通过受精前拍摄的照片测得。`Egg size`（卵大小）代表每枚卵子在受精前的初始尺寸，其值通过结合描述卵子受精前后尺寸关系的公式，由受精后测得的尺寸反向推算得到。