Figure 1. Milk components by offspring sex.

(a) protein (b) carbohydrate and (c) lipid content in milk during phase 2B and phase 3 of lactation in wallabies birthing sons (shaded) or daughters (unshaded). Females allocate significantly more protein to sons during Phase 2B of lactation than to daughters, while females allocate both carbohydrates and lipids equally to sons and daughters during phase 2B and 3 of lactation. Levels not connected by the same letter are significantly different (post-hoc Student’s t-test).