Offspring wet weight and fat
Over the duration of the experiment, 570 pupae from the control group, 301 from the mating delay group and 369 from the nutritional stress group were produced. Of these 1209 were weighed, as 31 were damaged before weighing. There was an average of six pupae larviposited per individual mother in the control group (range one to eight) and four from both the mating delay (range one to six) and nutritional stress (range one to seven) groups.
For all three treatment groups, the wet weight of pupae increased as mothers aged up until c. 60 days and then declined until the end of the experiment at 100 days (Fig. 4, Tables S4.7-9). The fitted curves and coefficients were similar between treatment groups, but pupae from nutritionally stressed mothers were overall smaller than those from the control or mating delay groups (Fig. 4, Table S4.9). For all three treatments, there was evidence for individual variation among mothers in the weight of their pupae and the effect of age (models with random intercept and slope: control ω = 0.992; mating delay ω = 0.909; nutritional stress ω = 0.993). This variation was more pronounced in the mating delay group compared to the other two treatments with a random intercept variance of 31.6, compared with 8.1 for the control group and 2.0 for the nutritional stress group (Table 1, Table S4.9).
In general, offspring fat increased linearly with offspring wet weight (Fig. S6), thus for brevity we focus on wet weight as our trait of interest but the patterns are qualitatively similar if offspring fat is considered instead.