ESM Table 1. Model selection for the effect of spawning order on proportion of eggs fertilized (Fert), latency to spawn (Lat),round dance rate (Dances) and clutch size (Clutch) . Spawning order (spawning), clutch size (clutch) and measures of body size (mass and standard length (SL)) are fixed variables; males are random factors. Measures of body size were transformed to Z-scores and are shown only when they were retained in the model for a given response variable. Models that best fit the data are in bold and were assessed by comparing AIC values and assessing significance of likelihood ratios. Asterisks indicate that removal of the term present in the previous model resulted in a significant change in model fit (*p<0.05, **p<0.01, ***p<0.001).

Model / df / AIC / BIC / Log likelihood / Likelihood ratio
Proportion of eggs fertilized
Fert ~ spawning* clutch, random = ~ spawning|male / 9 / 1450.380 / 1478.812 / -716.190
Fert~spawning*clutch, random= ~1|male / 7 / 1448.072 / 1470.185 / -717.036 / 1.692
Fert~spawning+clutch, random = ~1|male / 6 / 1448.674 / 1467.628 / -718.337 / 2.601
Fert~spawning, random = ~1|male / 5 / 1447.160 / 1462.955 / -718.580 / 0.486
Fert~1, random = ~1|male / 4 / 1483.741 / 1496.378 / -737.871 / 38.581***
Latency to spawning
Lat~spawning, random= ~ spawning|male / 7 / 369.275 / 391.388 / -177.637
Lat~spawning, random= ~ 1|male / 5 / 365.532 / 381.327 / -177.766 / 0.257
Lat~ 1= ~ 1|male / 4 / 365.855 / 378.491 / -178.927 / 2.323
Round dance rate
Dances ~ spawning+SL+mass, random = ~ spawning|male / 9 / 157.498 / 184.830 / -69.749
Dances ~spawning+SL+mass, random= ~1|male / 7 / 156.168 / 177.427 / -71.084 / 2.671
Dances~spawning+ mass, random = ~1|male / 6 / 154.455 / 172.677 / -71.227 / 0.286
Dances~spawning, random = ~1|male1 / 5 / 157.971 / 173.155 / -73.985 / 5.516 *
Dances~ mass, random = ~1|male1 / 5 / 161.54 / 176.725 / -75.770 / 9.085**
Clutch size
Clutch~spawning+SL+mass, random = ~spawning|male / 9 / 146.360 / 173.693 / -64.180
Clutch~spawning+ SL+mass, random = ~1|male / 7 / 142.359 / 163.618 / -64.179 / 0.0013
Clutch~spawning+SL, random = ~1|male / 6 / 141.884 / 160.106 / -64.942 / 1.525
Clutch~spawning, random = ~1|male1 / 5 / 145.116 / 160.301 / -67.558 / 5.232*
Clutch~SL, random = ~1|male1 / 5 / 153.933 / 169.118 / -71.966 / 14.048***

1 These models were each compared to the best fit model