Estimated marginal means (± 95% CI) of
z-transformed half-weight index of dyadic association of female
chimpanzees in relation to the presence of immature male versus female offspring
of both members of the dyad, estimated at the population mean level of core area
overlap for each group (z score = 0). Labels on
X axis indicate, for females A and B in a given dyad,
whether either one had at least one male (M+) or female (F+)
offspring in a given period, or neither (0). The first group represents dyads of
two females without immature offspring, and all subsequent groups are sorted by
their mean estimated association index. Numbers above or below error bars
indicate the number of unique dyads in each group, across all periods.