Supporting Information

Dataset of hatching-timing field observations from Experiment 1. The number of naturally and artificially hatched individuals and their developmental stage in each cluster, on each observation day. For defining the developmental stage, we used the table for the normal stage of development of a hynobiid salamander,Hynobius nigrescens Stejneger (Iwasawa & Yamashita, 1991), one of the closely related species of our study species Hynobius retardatus in this report.
Dataset from Experiment 1. Developmental stage (DS) and morphological traits: body length (BL; tip of thesnout to tip of tail), head width (HW), gape width (GW), snout–vent length (SVL; tip of the snout totheposterior end of the cloaca), and tail length (TAL; posterior end of the cloacato tip of the tail) in each replicates in Experiment 1. The R code used for statistical analyses and figure generation for this experiment (Figure 2) is provided as “R code for Experiment 1.”
Dataset from Experiment 2. Body length of early- and late-hatched individuals in Experiment 2. The R code used for statistical analyses and figure generation for this experiment (Figure 3B) is provided as "R code for Experiment 2."
Dataset from Experiment 3. Body length and gape width ofpredators assigned to the early- and late-hatch treatments;and body length, head width and survival time of early- and late-hatched individuals in Experiment 3. The R code used for statistical analyses and figure generation for this experiment (Figure 4) is provided as "R code for Experiment 3."