Figure 3: Performance and fitness measures of offspring under different family social conditions.

(a) The time to dispersal of offspring from the carcass, measured in hours (h) from egg hatching. All offspring disperse together so there is a single dispersal time per brood. Once offspring disperse they do not feed again until they are adults. The speed with which they can disperse reflects the rate at which they are able to utilize the carcass. (b) The mass of the dispersing broods, reared under different parental social groups. Mass of each dispersing larva was measured individually, but data were analysed as mean offspring mass to avoid inflating degrees of freedom. Once offspring disperse, they do not feed again so final adult size is determined by mass at dispersal, and larger males and females are more likely to successfully defend resources for breeding. (c) Offspring survival to adult, measured as the percentage of offspring that dispersed that survived to adult pupation, under different parental social groups. Data are presented using box plots, with medians (inner line; where there is no inner line, the median and 25% quartile overlap), 25 and 75% quartiles (boxes) and whiskers (end of box to 1.5 × interquartile range). The dots are values that fall outside the interquartile range. Analyses are based on 138 biparental families, 119 uniparental female families and 13 uniparental male families.